WO2013135102A1 - 开销修改及防止子网同时倒换的方法、装置、网元和网络 - Google Patents

开销修改及防止子网同时倒换的方法、装置、网元和网络 Download PDF

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Publication number
WO2013135102A1
WO2013135102A1 PCT/CN2013/000277 CN2013000277W WO2013135102A1 WO 2013135102 A1 WO2013135102 A1 WO 2013135102A1 CN 2013000277 W CN2013000277 W CN 2013000277W WO 2013135102 A1 WO2013135102 A1 WO 2013135102A1
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WIPO (PCT)
Prior art keywords
subnet
modification
overhead
signal
protection switching
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PCT/CN2013/000277
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English (en)
French (fr)
Inventor
苑岩
富森
宋晓鹏
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中兴通讯股份有限公司
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Application filed by 中兴通讯股份有限公司 filed Critical 中兴通讯股份有限公司
Priority to EP13760440.1A priority Critical patent/EP2827506B1/en
Publication of WO2013135102A1 publication Critical patent/WO2013135102A1/zh

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/74—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission for increasing reliability, e.g. using redundant or spare channels or apparatus
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/14—Monitoring arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/16—Time-division multiplex systems in which the time allocation to individual channels within a transmission cycle is variable, e.g. to accommodate varying complexity of signals, to vary number of channels transmitted
    • H04J3/1605—Fixed allocated frame structures
    • H04J3/1652—Optical Transport Network [OTN]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/16—Time-division multiplex systems in which the time allocation to individual channels within a transmission cycle is variable, e.g. to accommodate varying complexity of signals, to vary number of channels transmitted
    • H04J3/1605—Fixed allocated frame structures
    • H04J3/1652—Optical Transport Network [OTN]
    • H04J3/1664—Optical Transport Network [OTN] carrying hybrid payloads, e.g. different types of packets or carrying frames and packets in the paylaod

Definitions

  • the present invention relates to the field of transmission equipment and optical transmission network in the field of communications, and in particular, to a method, device, network element and network for overhauling and preventing simultaneous subnet switching.
  • OTN Optical Transport Network
  • ODUi signal Optical channel Data Unit
  • Only the ODUi signal is processed internally, and various non-optical transport network signals that need to be transmitted by the optical transport network are converted into suitable ODUi signals when entering the access point of the optical transport network, and the ODUi signals are transmitted in the optical transport network.
  • the various non-optical transport network signals are demapped from the ODUi until the destination point is reached, thereby enabling transmission of various non-optical transport network signals between the access point and the destination on the optical transport network.
  • ODUi can only exist inside the optical transport network equipment.
  • ODUi Optical Transform Unit
  • OTUk Optical Transform Unit
  • the optical transport network is the network with the longest transmission distance, and its network structure is also the most complicated compared to other communication networks.
  • a site that processes an optical transport network signal is called a network element, and a plurality of network elements are connected by an optical transport network signal OTUk to form a subnet (referred to as an optical transport subnet in the text), and an optical transport network generally has multiple sub-networks.
  • Each subnet may belong to a device of a different device vendor or carrier.
  • the device of the same device vendor or carrier may also be divided into multiple subnets according to the geographical relationship.
  • the optical transport network may implement subnet-based protection switching.
  • FIG. 1 shows two optical transport subnets with protection switching functions connected in series, wherein network elements 1 to 6 form a subnet A with 1+1 protection switching function, wherein network elements 1, 2, 3 4 is the working path, and the network elements 1 , 5, and 6 are the protection paths; the network elements 7 to 12 form a subnet B having the 1+1 protection switching function, wherein the network elements 7, 8, 9, 10 are working. Path, network elements 7, 11, 12, 10 are protection paths.
  • the two subnets in Figure 1 are connected in series.
  • the optical transport network supports subnet protection switching, and the subnet protection switching is implemented by the tandem connection monitoring (TCM) overhead.
  • TCM overhead is the overhead of the subnet performance detection defined in the optical transport network.
  • the TCM has six levels, namely TCM1-TCM6. After a reasonable division of the TCM usage range, the TCM can be used to separately detect the subnet status and exclude other The effect of the subnet on the status of this subnet.
  • each subnet supporting the protection switching needs to be assigned a TCM overhead. Each subnet determines whether the protection switching needs to be triggered by detecting the state of the TCM overhead allocated to it.
  • TCM1 overhead For the tandem subnet in the above figure, you can assign TCM1 overhead to both subnet A and subnet B.
  • the dotted line in the figure is the transmission path of the TCM overhead.
  • the TCM overhead is transmitted together with the service.
  • Subnet A uses the TCM1 overhead as its protection switching.
  • the starting point of TCM1 is that the end point of network element 1 is network element 4, and the subnet B also uses TCM1 as the basis for determining the protection switching.
  • the starting point of TCM1 is the end point of network element 7 is network element 10, so that the network element 4 in the above figure Both the network element 10 and the network element 10 determine whether the switching should be protected according to the state of the TCM1 overhead.
  • ODUi-AIS Alarm Indication Signal
  • ODUi-AIS is the maintenance signal of the optical transport network signal defined by the optical transport network standard.
  • the value of the TCM1-STAT overhead is 111, indicating that it is in the TCM1-AIS state.
  • the network element 4 finds that the TCM1-STAT is in the TCM1-AIS state by detecting the TCM1-STAT overhead.
  • the service is considered to be invalid, and the network element 4 starts protection switching, and there is no protection switching.
  • the ODUi-AIS signal sent by the network element 3 is transparently transmitted before the system is effective. Since the network element 4 is the end point of the TCM1, the network element 4 changes the TCM1-STAT overhead in the ODUi-AIS output to the TCM1-LTC state. , indicating TCM1 overhead The resource has been released. After the ODUi-AIS sent by the network element 4 is transmitted to the network element 7 of the subnet B, since the network element 7 is the starting point of the TCM1, the TCM1 overhead in the received ODUi-AIS is changed to the TCM1 -NORMAL state.
  • the ODUi-AIS is transparently transmitted by the NEs 10 and 9 so that the TCM1-STAT overhead received by the downstream network element 10 from the network element 9 is displayed in the TCM1-NORMAL state.
  • the network element 10 considers that the TCM1 is normal, so the network element 10 receives the network element. 4 Protection switching does not occur when ODUi-AIS is sent. After the network element 4 is switched and switched to the network element 6, the service is restored to normal and the ODUi-AIS disappears.
  • the network element 10 in the subnet B will always detect TCM1, and the TCM1 will always be normal, so the network element 10 will not be switched, so that the switching of network element 4 will not cause the network element 10 to switch, so that the protection switching between the two subnets will not affect each other.
  • the existing TCM-based subnet protection technology in the optical transport network can ensure that the protection switching of two subnets with serial connection does not affect each other.
  • the protection switching systems of the two subnets also have a nested relationship, and the sub-inserts are embedded in another subnet.
  • the protection switching action of the network is likely to cause the subnet in which the subnet is embedded (referred to as the jacket subnet in the text) to protect the switching error trigger or the protection switching timeout.
  • the embedded subnet with a nested relationship and the corresponding outer subnet refer to all the network elements in the embedded subnet are located on the working or protection path in the outer subnet (but not at work at the same time). And on the protection path).
  • the jacket subnet corresponding to an embedded subnet refers to all the jacket subnets in which the embedded subnet is embedded, and may have one or more, and the embedded subnet corresponding to one jacket subnet is embedded in the jacket subnet. All embedded subnets can have one or more, that is, nesting between subnets can be multiple layers of nesting between three or more subnets.
  • a pair of subnets with nested relationships and protection switching functions can be directly nested or indirectly nested. The so-called directly nested pair of subnets means that there is no other pair between the pair of subnets.
  • a subnet with protection switching function such as subnet A and subnet B in Figure 3.
  • an embedded subnet or a subnet that is both a jacket subnet and an embedded subnet is an optical transport subnet, and only one outer jacket subnet may be a non-optical transport subnet. Or an optical transmission subnet.
  • the subnets having the nested relationship shown in FIG. 3 are all optical transport networks, wherein the network elements 1 to 6 form a subnet B having a 1+1 protection switching function, wherein the network elements 1 , 2, 3 , 4 are Working path
  • the elements 1 , 5 , and 6 are protection paths.
  • the dotted line in the figure is the transmission path of the TCM1 overhead.
  • the TCM1 overhead is valid in the subnet B.
  • the starting point is the network element 1 and the destination is the network element 4, which is transmitted together with the service. B determines whether to protect the switching according to the state of the TCM1.
  • the network elements 1-10 form a subnet A with a 1+1 protection switching function, where the network elements 7 , 1 , 2 , 3 , 4 , 10 are working paths, and the network element 7 , 8 , 9, 10 is the protection path, the dotted line in the figure is the transmission path of the TCM2 overhead, the TCM2 overhead is valid in the subnet A, and the starting point is the end point of the network element 7 is the network element 10, and is transmitted together with the service, and the subnet A is based on The state of TCM2 determines whether protection switching is guaranteed.
  • the subnet B is embedded between the network elements 1 and 4 of the subnet A, which is an embedded subnet, and the subnet A is a jacket subnet. In the environment shown in Figure 3, subnets A and B must use different TCM overheads to ensure that each subnet can detect the working status of its own subnet.
  • NE 3 replaces the failed ODUi signal with ODUi-AIS, where TCM1-STAT overhead and TCM2-STAT overhead. Both are in the TCM1-AIS state.
  • the network element 4 finds that the service is in the TCM1-AIS state, and the service is invalid.
  • the network element 4 starts the protection switching, and the network element 3 is transparently transmitted before the protection switching is effective.
  • the ODUi-AIS signal is sent. Since the network element 4 is not the starting point of the TCM2, the TCM2-STAT overhead in the ODUi-AIS is transparently transmitted.
  • the network element 10 After the ODUi-AIS is transmitted to the network element 10 of the subnet A, the network element is transmitted.
  • the received TCM2-START overhead is also displayed in the TCM2-AIS state.
  • the network element 10 considers that the service is invalid, triggering the protection switching and switching over the protection paths of the network elements 8 and 9, such that the network element A and the network element B
  • the protection switching system will start at the same time, which is equivalent to a fault that triggers the protection switching action of two different protection switching systems on the same path. This will easily lead to a long service interruption time caused by the action of the protection switching system. It may even cause the protection switching system to switch over timeout.
  • the first solution is to ignore the two protection systems and protect the switching phenomenon at the same time. No remedial measures are taken. When the nesting phenomenon is very serious, the first solution will not be feasible.
  • the NE that performs the protection switching switch considers that the service failure within the last Th time is normal and does not trigger protection switching. Only when the service fails. The protection switching will be started after Th is exceeded.
  • scheme 2 can ensure that the protection switching occurs only once during the failure of the embedded subnet, and the protection switching time does not time out, but if the fault point occurs in the jacket subnet and the embedded subnet, for example, the network element 4 to the network
  • the fiber connection between the elements 10 is interrupted. Due to the existence of Th of the network element 10, the service transient time caused by the protection switching must be greater than Th.
  • the NEs that perform protection switching in the subnet subnet need to set different settings for Th according to whether the embedded subnet supports protection switching, which will increase the workload of manual maintenance.
  • Figure 5 gives an example.
  • the non-optical transport network elements C1 to C6 and 1 to 8 form a non-optical transmission subnet having a protection switching function
  • the optical transmission network elements 1 to 8 form two optical transmission subnets, wherein the network element 1
  • the optical transmission subnet consisting of 6 has a protection switching function.
  • the interface signal between the optical transport subnet and the non-optical transport subnet is an Ethernet signal (for example, 10GBASE-R defined by IEEE802.3), and the signal inside the optical transport network is an optical transport network signal (for example, OTU2e).
  • the network topology is actually the same as the two optical transmission subnets with protection switching function shown in Figure 3, but the subnets with nested relationships in Figure 3 are optical transport subnets.
  • the same layer of equipment, and Figure 5 is the optical transmission subnet nested in the non-optical transmission subnet, is a different layer of equipment.
  • the network of FIG. 5 has the same problem as FIG. 3.
  • the network element C6 needs to set Th, and the Th value is greater than the longest service interruption time that may occur when the optical transmission subnet is protected and switched.
  • the default Ethernet device will default to set Th to 100ms, which can avoid the Ethernet device switching at the same time when the protection switching occurs in the optical transmission network.
  • the non-optical transport network equipment is a PTN equipment, its function is similar to that of a conventional Ethernet equipment, but at the same time it has the reliability of the transmission equipment and the protection switching time requirement.
  • the required protection switching time is the same as that of the optical transmission network.
  • the setting of Th is the protection switching time of the optical transport network. Similar to FIG. 4, when the network element 4 to C4 or the network element C1 to the network element 1 have a fiber break and the working channel is on the path of C1 to C4, the non-optical transmission is performed.
  • the protection switching time of the subnet will be greater than Th, which will exceed the maximum protection switching time allowed by the PTN device.
  • the workload of manual maintenance will also increase.
  • the technical problem to be solved by the present invention is to provide an overhead modification method and corresponding cost modification apparatus and network element that can temporarily block out the overhead information that is output to the downstream network element, which triggers the subnet protection switching.
  • the present invention provides an overhead modification method, which is applied to a network element embedded in an optical transmission subnet.
  • the method includes: detecting that a fault occurs, and the fault triggers the embedded optical transmitter.
  • the value of the jacket subnet protection switching is triggered, and the modification does not modify the overhead of triggering the embedded optical transmission subnet protection switching; after the modification continues for a period of time, the modification is cancelled, and the period of time is less than or equal to the setting.
  • the duration of the modification is applied to a network element embedded in an optical transmission subnet.
  • the cost modification method is applied to all network elements in the embedded optical transmission subnet; the detecting that a fault occurs occurs that the optical channel data unit (ODU) layer is detected to be invalid;
  • the signal transmitted to the downstream network element refers to an ODUi alarm indication signal (ODUi-AIS signal) inserted to replace the failed optical channel data unit signal (ODUi signal).
  • ODUi-AIS signal ODUi alarm indication signal
  • the cost modification method is applied to a network element that performs the embedded optical transmission subnet protection switching handover in the embedded optical transmission subnet; and the detected fault occurrence occurs, according to the ODUi before the ODU layer failure processing.
  • the signal detects that the tandem connection monitoring (TCM) layer detected when the protection switching process is performed in the embedded optical transmission subnet becomes a failure; the signal to be transmitted to the downstream network element refers to the normal output after the ODU layer fails to be processed.
  • TCM tandem connection monitoring
  • the overhead of triggering the embedded optical transport subnet protection switching is the TCMn-STAT overhead allocated to the embedded optical transport subnet, l ⁇ n ⁇ 6;
  • the jacket subnet has one or more, wherein the outermost jacket subnet is an optical transmission subnet or a non-optical transmission subnet, and if there are other jacket subnets, the other jacket subnets are optical transmission subnets.
  • the overhead that triggers the jacket subnet protection switching is the TCMn-STAT overhead allocated to the jacket subnet;
  • the overhead that triggers the jacket subnet protection switching is the PM-STAT overhead.
  • the value of the overhead that will trigger the jacket subnet protection switching is modified to not trigger the value of the jacket subnet protection switching, including: for the jacket subnet for the optical transmission subnet,
  • the value of the TCMn-STAT overhead is modified to one of the three-bit 011, 100, 001, and 010.
  • the value of the PM-STAT overhead is changed to 3.
  • the set modification duration is the longest service interruption time that may be caused when the embedded optical transmission subnet is protected and switched.
  • the network element of the embedded optical transmission subnet belongs to only one embedded optical transmission subnet; or the network element of the embedded optical transmission subnet belongs to multiple embedded optical transmission subnets at the same time, and the overhead modification method
  • the embedded optical transport subnet in the middle refers to the innermost embedded optical transport subnet.
  • the detecting that the TCM layer detected when performing the protection switching process in the embedded optical transmission subnet becomes invalid includes: detecting one or more of the following conditions: the service layer of the TCM layer is changed. Invalid; the TCM layer becomes an AIS, LCK, OCI, or LTC state.
  • canceling the modification includes: setting the modification duration to expire, canceling the modification; or
  • canceling the modification includes: if the set modification duration expires, the ODU layer has not returned to normal, canceling the modification; and during the set modification duration, such as detecting After the ODU layer returns to normal, the modification is immediately cancelled.
  • canceling the modification includes: setting the modification duration to expire, canceling the modification; or
  • canceling the modification includes: if the TCM layer has not returned to normal after the set modification duration expires, canceling the modification; and during the modification duration of the setting, such as detecting The TCM layer is restored to normal and the modification is immediately cancelled.
  • canceling the modification further includes: during the set modification duration, if it is detected that the fault cannot be recovered by the protection switching system of the embedded optical transmission subnet, Cancel the modification immediately.
  • the present invention provides an overhead modification apparatus in a network element embedded with an optical transport subnet, including a modification control unit and an overhead modification unit, where:
  • the modification control unit is configured to: notify the overhead modification unit to modify the overhead when detecting that a fault occurs, wherein the fault triggers the embedded optical transmission subnet and the embedded optical transmission is embedded therein The subnet protection switching of the subnet and having the protection switching function; and after the modification for a period of time, notifying the overhead modification unit to cancel the modification, the period of time is less than or equal to the set modification duration; the cost modification unit is set to When the modification control unit notifies the modification, the value of the overhead that will be triggered to be transmitted to the downstream network element is triggered to be modified to not trigger the value of the jacket subnet protection switching, and The modification triggers the overhead of the embedded optical transport subnet protection switching; and cancels the modification when the modification control unit notifies the cancellation of the modification.
  • the cost modifying device is applied to all network elements of the embedded optical transmission subnet;
  • the modification control unit is configured to: according to the input optical channel data unit (ODU) layer failure indication signal, used to indicate overhead Whether the modified overhead indication signal and the set modification duration signal are output, and the modification indication signal is output, wherein the modification indication signal indicates that the modification is indicated by the overhead indication signal when the ODU layer failure indication signal indicates that the ODU layer becomes invalid
  • the modified triggers the overhead of the jacket subnet protection switching and does not modify the overhead indicated by the overhead indication signal to be unmodifiable, which triggers the overhead of the embedded optical transmission subnet protection switching, and notifies the overhead modification unit after the modification continues for a period of time. Cancel the modification, the period of time is less than or equal to the set modification duration;
  • the overhead modification unit is configured to: input according to the indication of the modification indication signal
  • the value of the overhead of the jacket subnet protection switching is changed to not trigger the value of the jacket subnet protection switching, and the inline optical transmitter is triggered without modification.
  • the overhead of the network protection switching is then output; and the modification is cancelled according to the indication of the modification indication signal.
  • the cost modifying device is applied to the network element that performs the protection switching of the embedded optical transmission subnet in the embedded optical transmission subnet, and further includes:
  • the serial connection monitoring (TCM) layer failure detecting unit is configured to: detect a TCM layer specified in the ODUi signal before the ODU layer failure processing, and output a TCM layer failure indication signal indicating whether the TCM layer is valid, wherein the specified TCM
  • the layer is an input TCM layer indication signal indicating a TCM layer detected when the protection switching process is performed in the embedded optical transmission subnet;
  • the modification control unit is configured to: output a modification indication signal according to the input TCM layer failure indication signal, an overhead indication signal for indicating whether the overhead can be modified, and the set modification duration signal, where the modification indication signal is When the TCM layer failure indication signal indicates that the TCM layer becomes invalid, indicating that the modification is indicated by the overhead indication signal to be modifiable may trigger the corresponding jacket subnet protection.
  • the overhead of the switching and not modifying the overhead indicated by the overhead indication signal may trigger the overhead of the embedded optical transmission subnet protection switching, and after the modification continues for a period of time, notify the overhead modification unit to cancel the modification, and the period of time is less than or equal to The set modification duration;
  • the cost modifying unit is configured to: according to the indication of the modification indication signal, the normal ODUi signal outputted after the ODU layer is invalidated or the inserted ODUi-AIS signal triggers the overhead of the corresponding jacket subnet protection switching The value is modified to not trigger the value of the jacket subnet protection switching and does not modify the overhead that triggers the embedded optical transmission subnet protection switching, and then outputs; and cancels the modification according to the indication of the modification indication signal .
  • the embedded optical transmission subnet network element has one or more outer jacket subnets, wherein the outermost outer casing subnet is an optical transmission subnet or a non-optical transmission subnet, and if there are other outer casing subnets, The other jacket subnets are optical transmission subnets;
  • the overhead indicated by the modification control unit that triggers the embedded optical transport subnet protection switching is the TCMn-STAT overhead allocated to the embedded optical transport subnet, l ⁇ n ⁇ 6;
  • the overhead indicated by the modification control unit triggers the corresponding jacket subnet protection switching.
  • the jacket subnet is an optical transmission subnet
  • the overhead of triggering the jacket subnet protection switching is allocated to The TCMn-STAT overhead of the jacket subnet; if the jacket subnet is a non-optical transmission subnet, the overhead that triggers the jacket subnet protection switching is the PM-STAT overhead.
  • the cost modifying unit is configured to: modify the value of the overhead that triggers the corresponding jacket subnet protection switching to not trigger the value of the jacket subnet protection switching, including:
  • the value of the TCMn-STAT overhead is modified to one of 3 bits of 011, 100, 001, 010; for the jacket subnet that is a non-optical transmission subnet, The value of the PM-STAT overhead is modified to one of the 3-bit 000, 010, 011, 100.
  • the network element of the embedded optical transmission subnet belongs to only one embedded optical transmission subnet; or the network element of the embedded optical transmission subnet belongs to multiple embedded optical transmission subnets at the same time, the modification control unit The embedded optical transmission subnet on which the innermost embedded optical transmission subnet is used as control is used.
  • the TCM layer failure detecting unit is configured to: detect that the TCM layer detected when performing the protection switching process in the embedded optical transmission subnet becomes invalid, including: detecting one or more of the following conditions : The service layer of the TCM layer becomes invalid; the TCM layer becomes AIS, LCK, OCI or LTC status.
  • the modification control unit is configured to: after the modification for a period of time, notify the cost modification unit to cancel the modification, including: the modification control unit notifying the cost modification unit to cancel the modification when the set modification duration expires; or The modification control unit notifies the overhead modification unit to cancel the modification when the set modification duration expires, such as the ODU layer or the TCM layer, and the modification modification duration, such as the ODU layer or the TCM.
  • the layer is restored to normal, and the cost modification unit is immediately notified to cancel the modification; wherein the set modification duration is the longest service interruption time that may be caused when the embedded optical transmission subnet is protected and switched.
  • the present invention provides a network element for embedding an optical transmission subnet, including an optical channel data unit (ODU) layer failure processing device and an overhead modification device, wherein: the overhead modification device uses the above-mentioned One of the overhead modification devices based on ODU layer failure detection;
  • ODU optical channel data unit
  • the ODU layer failure processing device includes an ODU layer failure detecting unit and a selecting unit, wherein:
  • the ODU layer failure detecting unit is configured to: detect, according to the ODU overhead in the optical channel data unit signal (ODUi signal), whether the ODU layer is invalid, and output an ODU layer failure indication signal to the overhead modifying device and the selecting unit;
  • the selecting unit is configured to: when the ODU layer failure indication signal indicates that the ODU layer is normal, output an ODUi signal, and when the ODU layer failure indication signal indicates that the ODU layer is invalid, output the unmodified or modified ODUi from the overhead modifying device.
  • Alarm indication signal ODUi-AIS signal
  • the present invention further provides a network element for performing the embedded optical transmission subnet protection switching handover in an embedded optical transmission subnet, including an optical channel data unit (ODU) layer failure processing device and an overhead modification device, wherein The overhead modification device uses one of the above-mentioned overhead modification devices based on the TCM layer detection of the present invention;
  • ODU optical channel data unit
  • the ODU layer failure processing device is configured to: output a normal optical channel data unit signal (ODUi signal) when the ODU layer is normal, and output an ODUi alarm indication signal (ODui) inserted to replace the failed ODUi signal when the ODU layer fails. -AIS signal).
  • ODUi signal normal optical channel data unit signal
  • ODui ODUi alarm indication signal
  • the above solution can temporarily block the overhead information that is output to the downstream NEs, which triggers the protection of the jacket subnet protection, and prevents the nested subnets from being switched at the same time.
  • Another technical problem to be solved by the present invention is to provide an optical transport network signal to a non-optical transport network signal.
  • the conversion method of the number and the corresponding device and network element can shield the maintenance information output to the downstream network element to trigger the jacket subnet protection switching according to the modification of the PM layer overhead after the failure.
  • the present invention provides a method for converting an optical transmission network signal to a non-optical transmission network signal, which is applied to a network element that performs demapping of a non-optical transmission network signal from an optical transmission network signal, the network
  • the network where the meta is located includes an embedded optical transport subnet and a jacket non-optical transport subnet having a nested relationship, and the conversion method includes:
  • the non-optical transport network maintenance signal, the first non-optical transport network maintenance signal is a non-optical transport network maintenance signal that triggers the non-optical transport network element protection switching.
  • the embedded optical transmission subnet network element does not trigger the value of the non-optical transmission subnet protection switching after the modification of the PM-STAT overhead, and is one of 3 bits of 000, 010, 011, 100 Kind.
  • the non-optical transport network signal is a signal encoded by a physical coding sublayer (PCS), and the second non-optical transport network maintenance signal is a signal that has no data frame and is all idle frames; or the non-light
  • the transport network signal is a Synchronous Digital Hierarchy (SDH) signal
  • the second non-optical transport network maintenance signal is a signal that the payload areas are all fixed values and the regeneration section and the multiplex section overhead are normal.
  • the present invention further provides a conversion device for transmitting an optical transmission network signal to a non-optical transmission network signal, which is applied to perform a network element for de-mapping a non-optical transmission network signal from an optical transmission network signal, where the network element is located
  • the network includes an embedded optical transmission subnet having a nested relationship and a jacket non-optical transmission subnet, and the conversion device includes:
  • the optical channel data unit signal (ODUi) demapping unit is configured to: demap the non-optical transport network signal from the ODUi signal;
  • the optical channel payload unit (OPU) layer failure detecting unit is set to: according to the ODUi signal
  • the cost of the ODU and the OPU layer is determined by the value of the PM-STAT overhead, and the value of the non-optical transmission subnet protection switching is not triggered by the embedded optical transmission subnet. Determining whether the OPU layer is invalid, and outputting a selection control signal according to the detection result;
  • a selecting unit configured to: select an output from the input non-optical transport network signal, the first non-optical transport network maintenance signal, and the second non-optical transport network maintenance signal according to the selection control signal; wherein, the second The non-optical transport network maintenance signal is a non-optical transport network maintenance signal that does not trigger the non-optical transport network element protection switching.
  • the first non-optical transport network maintenance signal is a non-optical transport network that triggers the non-optical transport network element protection switching. Maintenance signal.
  • the OPU layer failure detecting unit is configured to output a corresponding selection control signal in the following manner:
  • the value of the PM-STAT overhead in the ODUi signal is equal to the value of the non-optical transmission subnet protection switching that is modified after the PM-STAT overhead is modified, and the output is used to select the second non-optical transmission network maintenance signal. Selection control signal;
  • the output is used to select the first non-optical transmission network.
  • Signal selection control signal
  • the value of the PM-STAT overhead is not equal to the value of the non-optical transmission network signal when the modified PM-STAT overhead does not trigger the non-optical transmission subnet protection switching and the OPU layer is normal. control signal.
  • the OPU layer failure detecting unit uses one of 000, 010, 011, 100, which does not trigger the non-optical transmission subnet protection switching of the jacket;
  • non-optical transport network signal is a signal encoded by a physical coding sublayer (PCS), and the second non-optical transport network maintenance signal is a signal that has no data frame and is all idle frames; or, the non-light
  • the transport network signal is a Synchronous Digital Hierarchy (SDH) signal, and the second non-optical transport network maintenance signal is a signal that the payload areas are all fixed values and the regeneration section and the multiplex section overhead are normal.
  • SDH Synchronous Digital Hierarchy
  • the present invention also provides a network element for performing signal processing for de-mapping non-optical transport network signals from an optical transport network signal, including the above-described conversion apparatus of the present invention.
  • Another technical problem to be solved by the present invention is to provide a method for preventing simultaneous nesting of multiple subnets. Methods.
  • the present invention provides a method for preventing simultaneous nesting of multiple subnets, wherein the applied network includes a pair of embedded subnets and jacket subnets having protection switching functions and directly nested, wherein The embedded subnet is an optical transport subnet, and the method includes:
  • All the network elements of the embedded subnet perform the above-mentioned cost modification method based on the ODU layer failure detection of the present invention, or the network element that performs the embedded optical transmission subnet protection switching handover in the embedded subnet performs the foregoing An overhead modification method based on TCM layer failure detection;
  • the jacket subnet is an optical transmission subnet; or the jacket subnet is a non-optical transmission subnet, the method further comprising: performing demapping of the non-optical transmission network signal from the optical transmission network signal in the network
  • the network element performs the conversion method as described above.
  • no other optical transport subnets are nested in the embedded subnet;
  • the optical subnet is further embedded in the embedded subnet, and the network element performing the embedded optical transport subnet protection switching in the embedded subnet performs the foregoing cost modification method based on the TCM layer failure detection of the present invention.
  • the method further includes: performing, in each of the optical subnets of the embedded subnet, both the embedded subnet and the outer subnet, the optical element performing the optical transport subnet protection switching, performing the foregoing The overhead modification method of the TCM layer failure detection, and the embedded optical transmission subnet in the executed overhead modification method refers to the optical transmission subnet.
  • all the network elements of the embedded subnet perform the above-mentioned cost modification method based on the ODU layer failure detection in the present invention.
  • the network element performing the protection switching handover in the jacket subnet does not support setting the protection switching delay trigger time, or The protection switching delay triggering time is set to 0, or the protection switching delay triggering time is set to a non-zero value of less than or equal to 5 ms; or the network element executing the embedded optical transmission subnet protection switching is performed in the embedded subnet.
  • the protection switching delay trigger time set by the network element performing the protection switching handover in the jacket subnet is greater than or equal to the time required for completing the overhead modification and is less than or equal to 10 ms.
  • the present invention provides a network including a pair of subnets having a protection switching function and directly nested, wherein the embedded subnet is an optical transmission subnet, wherein:
  • the protection switching delay trigger time set by the NE that performs protection switching switching in the jacket subnet is smaller than the longest service interruption time that may be caused when the protection subversion occurs in the corresponding embedded subnet.
  • the jacket subnet is an optical transmission subnet; or the jacket subnet is a non-optical transmission subnet in which the network element that demaps the non-optical transmission network signal from the optical transmission network signal is used. A network element that demaps the signal processing from the optical transport network signal to the non-optical transport network signal is performed.
  • no other optical transport subnets are nested in the embedded subnet;
  • the optical subnet is embedded in the embedded subnet, and the network element performing the embedded optical transmission subnet protection switching in the embedded subnet is used in the embedded optical transmission subnet provided by the present invention.
  • the embedded optical transmission subnet protection switching network element in the optical subnet of the embedded subnet as both the embedded subnet and the outer subnet, performing the optical transmission subnet protection switching switching.
  • the network element uses the embedded optical transport subnet provided by the present invention to perform the embedded optical transport subnet protection switching handover and the overhead modification apparatus processes the optical transport subnet as an embedded optical transporter. network.
  • all the network elements of the embedded subnet use the network element of the embedded optical transmission subnet provided by the present invention, and the network element performing the protection switching handover in the outer subnet does not support setting the protection switching delay triggering time. Or set the protection switching delay trigger time to 0, or set the protection switching delay trigger time to a non-zero value less than or equal to 5 ms; or, the network element that performs the embedded optical transmission subnet protection switching in the embedded subnet.
  • the network element that performs the embedded optical transmission subnet protection switching switching in the embedded optical transmission subnet provided by the present invention, and the protection switching delay triggering time set by the network element performing protection switching switching in the outer casing subnet is greater than or equal to completion. The time required for cost modification is less than or equal to 10ms.
  • the switching delay triggering time Th can be set to a short value, such as a non-zero value of 0 or less than 10ms.
  • Th can be configured uniformly, reducing the workload of the configuration.
  • FIG. 1 is a networking diagram of two optical transmission subnets connected in series and having a protection switching function.
  • FIG. 2 is a schematic diagram of TCM overhead delivered by the network element 3 in FIG. 1 after detecting a fault.
  • Figure 3 is an exemplary networking diagram of two optical transport subnets with nested relationships and protection switching functionality.
  • FIG. 4 is a schematic diagram of TCM overhead delivered by the network element 3 in FIG. 3 after detecting a fault.
  • Fig. 5 is an exemplary networking diagram in which an optical transmission subnet having a protection switching function is nested in a non-optical transmission subnet having a protection switching function.
  • Fig. 6 is a view showing the structure and signal processing of a network element for performing mutual conversion of a non-optical transport network signal and an optical transport network signal.
  • FIG. 7 is a schematic diagram of an ODU layer failure processing method.
  • FIG. 8 is a schematic diagram of an OPU layer failure processing method.
  • Fig. 9 is a diagram showing the structure and signal processing of a network element for realizing mutual conversion between an optical transport network signal OTUk and an optical transport network signal OTUk.
  • FIG. 10 is a flowchart of a method for modifying an overhead according to Embodiment 1 of the present invention.
  • FIG. 11 is a schematic structural diagram of an apparatus for modifying an overhead according to Embodiment 1 of the present invention.
  • FIG. 12 is a flowchart of a method for modifying an overhead according to Embodiment 2 of the present invention.
  • FIG. 13 is a schematic structural diagram of an overhead modification apparatus and an ODU layer failure processing apparatus according to Embodiment 2 of the present invention.
  • FIG. 14 is a flowchart of a method for modifying an overhead according to Embodiment 3 of the present invention.
  • FIG. 15 is a schematic structural diagram of an overhead modification apparatus and an ODU layer failure processing apparatus according to Embodiment 3 of the present invention.
  • Figure 16 is an exemplary networking diagram of a plurality of optical transport subnets having a nested relationship and having a protection switching function.
  • Figure 17 is a flow chart showing a conversion method of the sixth embodiment of the present invention.
  • FIG. 18 is a block diagram showing the structure of a converting apparatus according to a sixth embodiment of the present invention.
  • FIG. 19 is another exemplary networking diagram in which an optical transmission subnet having a protection switching function is nested in a non-optical transmission subnet having a protection switching function.
  • Figure 20 is a diagram showing the network structure of the first application example of the present invention.
  • FIG. 21 is a schematic diagram of the state of each network element before the network element 3 detects the fault in the network element 4 before the protection switching is started.
  • Figure 22 is a diagram showing the network structure of the application example 2 of the present invention.
  • FIG. 23 is a schematic diagram of the state of each network element before the network element 3 detects the fault in the network element 4 before the protection switching is started.
  • FIG. 24 is a schematic diagram of the state of each network element before the network element 1 in FIG. 22 detects a fault until the network element C6 initiates protection switching.
  • the optical transport network element implements processing of the optical transport network signal, and the optical transport network signal includes
  • OTUk is responsible for transmitting ODUi between optical transport network elements.
  • One processing method is to implement non-optical transport network signals such as Ethernet, SDH (Synchronous Digital Hierarchy) signals, Fibre Channel signals (Fiber Channel) and light.
  • SDH Serial Digital Hierarchy
  • Fibre Channel Fibre Channel
  • the mutual conversion of the transmission network OTUk signals, and the other processing method is to realize the mutual conversion between the optical transmission network signal OTUk and the optical transmission network signal OTUk.
  • the optical transport network element has two service failure processing methods, one is the ODU layer failure processing method, and the other is OPU (Optical Channel Payload) Unit, optical channel payload unit) layer failure processing method.
  • the failure processing method of the optical transmission network element affects the protection switching of the optical transmission network and the non-optical transmission network element.
  • the failure processing method of the optical transmission network element can ensure that the failure state is stably transmitted between the network elements, thereby ensuring The NE that protects the switching function correctly detects the service failure status that occurs upstream and triggers protection. Switched.
  • Fig. 6 shows a signal processing procedure of a conventional network element that performs mutual conversion of a non-optical transport network signal and an optical transport network OTUk signal.
  • the network element implements n non-optical transport network signals (non-optical transport network signal 1, non-optical transport network signal 2, non-optical transport network signal n) to m optical transport network signals OTUk (OTUkl, OTUk2,. .., OTUkm), the conversion process is to convert the non-optical transmission network signal into the ODUi signal with the close rate, then the ODUi signal is scheduled by the ODUi cross matrix, and the n ODUi signals after scheduling are aggregated into m according to the needs of the user. A higher rate OTUk signal.
  • the ODU layer failure processing device is included in the conversion modules of the plurality of low-speed ODUi and ODUk for ODU layer failure processing.
  • the method refer to FIG. 7.
  • the ODUi-AIS signal is used to replace the failed ODUi signal and sent to the ODU cross-matrix.
  • the ODUi signal from the ODUk is ODUi-AIS.
  • the ODUi is considered to be the normal ODUi signal when the ODU layer fails to be detected. And transparently, it will not judge the ODU layer to fail and insert ODUi-AIS again.
  • the OPU layer failure processing device is included in the conversion module of the non-optical transmission network signal and the ODUi to perform OPU layer failure processing.
  • the method please refer to FIG. 8 to demap the non-optical transmission network signal from the ODUi (from the layered view, ODUi)
  • the signal is demapped to the non-optical transport network signal, first demapped to the OPU layer signal OPUi and then demapped to the non-optical transport network signal), it is detected whether the OPU layer is invalid. If it fails, the non-optical transport network maintenance signal is used to replace the non-light. Transport network signal.
  • the non-optical transport network signal and ODUi conversion module also includes an ODU layer failure processing device to perform ODU layer failure processing on the ODUi signal.
  • the optical transport network standard G.709 has definitions for common non-optical transport network maintenance signals, for example, SDH (Synchronous Digital Hierarchy, synchronization) Digital system) signal, non-optical transport network maintenance signal is PN-11; for 10GBASE-R Ethernet signal (IEEE 802.3 defined 10 Gigabit Ethernet signal),
  • the non-optical transport network maintenance signal is the Local Fault OrderSet.
  • the principle of the OPU layer failure processing method is that if an input signal failure is detected, a signal having a specific signal format, that is, a defined non-optical transmission network maintenance signal, is used instead of the failed signal to continue processing, which has a specific signal format. The signal will be considered as a signal failure by the device receiving it.
  • Figure 9 shows the optical transport network signal OTUk and the optical transport network signal OTUk (k is 1).
  • the ODU layer failure processing device is included in the conversion modules of the plurality of low-speed ODUi and ODUk in the figure to perform ODU layer failure processing, and the processing method is the same as the ODU layer failure processing device in FIG.
  • the embodiment provides a method for modifying an overhead applied to a network element of an embedded optical transmission subnet. As shown in FIG. 10, the method includes:
  • Step 110 detecting that a fault occurs, and the fault triggers the embedded optical transport subnet and the jacket subnet protection switching with the protection switching function embedded in the embedded optical transmission subnet; Step 120, to be transmitted to In the signal of the downstream network element, the value of the overhead of the jacket subnet protection switching is changed to not trigger the value of the jacket subnet protection switching, and the modification does not trigger the inline optical transmission subnet protection switching. s expenses;
  • Step 130 After the modification continues for a period of time, the modification is cancelled, and the period of time is less than the set modification duration.
  • the overhead modification apparatus applied to the embedded optical transmission subnet network element includes:
  • the modification control unit 10 is configured to notify the overhead modification unit to perform modification when detecting that a fault occurs, wherein the fault triggers the embedded optical transmission subnet and the embedded optical transmission subnet embedded therein and has a protection switching function The jacket subnet protection switching; and after the modification continues for a period of time, notifying the overhead modification unit to cancel the modification, the period of time being less than or equal to the set modification duration.
  • the cost modification unit 11 is configured to modify, when the modification control unit notifies the modification, that the value of the overhead of the jacket subnet protection switching is triggered in the signal to be transmitted to the downstream network element, so that the jacket subnet protection switching is not triggered.
  • the value of the embedded optical transmission subnet protection switching is triggered without modification. Pin; and cancel the modification when the modification control unit notifies the cancellation of the modification.
  • the cost modification method in this embodiment may temporarily mask the outage information that is output to the downstream network element to trigger the jacket subnet protection switching after the network element detects that the fault occurs, so that the network element in the jacket subnet cannot be perceived.
  • the built-in subnet protects the service transients generated during the switching, and thus the effect of the protection switching of the embedded subnet but temporarily does not trigger the protection of the jacket subnet protection.
  • the embodiment is based on the cost modification method of the ODU layer failure detection, and is applied to the network element of the embedded optical transmission subnet. As shown in FIG. 12, the method includes:
  • Step 210 detecting that the ODU layer becomes invalid
  • step 220 the value of the overhead of the corresponding UDUi-AIS signal that is triggered to replace the failed ODUi signal is changed to the value of the jacket subnet protection switching, and the value of the jacket subnet protection switching is not triggered.
  • the overhead of triggering the embedded optical transport subnet protection switching is the TCMn-STAT overhead allocated to the embedded optical transport subnet, 1 ⁇ n ⁇ 6;
  • the embedded optical subnet is embedded in the jacket subnet and has a protection switching function, and the jacket subnet corresponding to the embedded optical transmission subnet may have one or more, wherein the outermost jacket subnet is light. Transmitting a subnet or a non-optical transport subnet. If there are other jacket subnets, the other jacket subnets are optical transport subnets;
  • the overhead that triggers the jacket subnet protection switching is the TCMn-STAT overhead allocated to the jacket subnet;
  • the overhead that triggers the jacket subnet protection switching is the PM-STAT overhead.
  • the TCMn-STATs allocated to individual optical transport subnets with nested relationships are different from each other.
  • TCMn-STAT and PM-STAT overhead are the overheads defined in the G.709 standard,
  • the length is 3 bits, and its value (binary) meaning is defined as follows in G.709.
  • the value of TCMn-STATt can be one of 3 bits of 011, 100, 001, 010, and these values will not be triggered.
  • the jacket optical transmission subnet protection switching if the PM-STAT overhead is modified and modified to be PM-STATp, the value of PM-STATp can be one of 3 bits of 000, 010, 011, 100, transmitted from the optical These measurements of PM-STATp when the network signal demaps out the non-optical transport network signal
  • the value does not trigger the insertion of the non-optical transport network maintenance signal defined in the existing standard (which will trigger the non-optical transport network protection switching, referred to herein as the first non-optical transport network maintenance signal), which in turn leads to downstream non-optical transport network elements. Protection switching.
  • Step 230 in the set modification duration, if it is detected that the ODU layer returns to normal, step 240 is performed, otherwise, step 250 is performed;
  • the duration of the above modification is determined by the longest service momentary time that may be caused by the protection switching of the embedded subnet, such as the longest service momentary time.
  • Step 240 cancel the modification, and end
  • the insertion of the ODUi-AIS signal is cancelled after the ODU layer returns to normal, and the normal ODUi signal is used for subsequent processing.
  • the modification of the ODUi-AIS signal can be cancelled at the same time.
  • the modification of the ODUi-AIS signal is cancelled again when the set modification duration expires.
  • Step 250 After the set modification duration expires, the ODU layer has not returned to normal, and the modification is cancelled.
  • the ODU layer has not returned to normal, that is, the ODU layer is still in a failed state. After the modification of the ODUi-AIS is cancelled, the unmodified ODUi-AIS signal is inserted after the ODU layer is invalidated.
  • the network element applying the above method may belong to multiple embedded optical transmission subnets at the same time.
  • the embedded optical transmission subnet in the above method refers to the network element to which the network element belongs.
  • the innermost embedded optical transport subnet of the plurality of embedded optical transport subnets For example, the optical transport subnet C is embedded in the optical transport subnet B, and the optical transport subnet B is embedded in the optical transport subnet A.
  • the optical transmission subnet B is an embedded optical transmission subnet, and the overhead allocated to the optical transmission subnet A is modified, and the overhead allocated to the optical transmission subnet B is not modified, and the modification duration is set to light.
  • the cost modification method is implemented to use the optical transport subnet C as the embedded optical transport subnet, and the modification is assigned to the optical transport subnet. B and A overhead, do not modify the allocation to the optical transport subnet
  • the modification duration is set to the longest service momentary time that may occur when the protection switching occurs on the optical transmission subnet C.
  • the foregoing method may further add a process, that is, during the set modification duration, if it is detected that the ODU layer fails, the embedded optical subnet cannot be transmitted. When the protection switching system is restored, the modification is immediately cancelled.
  • the network element After the network element detects that the ODU layer is invalid, the network element temporarily masks the cost information of the subnet protection switching that is triggered by the network element, so that the network element in the jacket subnet cannot be perceived.
  • the business subnet generated during the protection switching of the embedded subnet.
  • the embodiment further provides an overhead modification device 21 based on the ODU layer failure detection, which is applied to the network element embedded in the optical transmission subnet, as shown in FIG. 13, including the modification control unit 211 and the overhead.
  • Modifying unit 212 where:
  • the modification control unit 211 is configured to output a modification indication signal according to the input ODU layer failure indication signal, the overhead indication signal for indicating whether the overhead can be modified, and the set modification duration signal, where the modification indication signal is at the ODU layer
  • the failure indication signal indicates that the ODU layer becomes invalid
  • indicating that the modification indicated by the overhead indication signal is modifiable may trigger the overhead of the corresponding jacket subnet protection switching, and if the modification is indicated by the overhead indication signal to be unmodifiable, the embedded light is triggered.
  • the overhead of transmitting the subnet protection switching, and after the modification continues for a period of time, notifying the overhead modification unit to cancel the modification, and the period of time is less than or equal to the set modification duration.
  • the cost modification unit 212 is configured to modify, according to the indication of the modification indication signal, the value of the overhead of the corresponding ODUi-AIS that triggers the corresponding jacket subnet protection switching to not trigger the value of the jacket subnet protection switching.
  • the modification does not modify the overhead of triggering the embedded optical transmission subnet protection switching, and then outputs; and cancels the modification according to the indication of the modification indication signal.
  • the overhead indication signal of the input modification control unit may be used as a parameter set by the network management system, and the modifiable overhead indicated by the indication includes an overhead that triggers the corresponding jacket subnet protection switching, and the unmodifiable overhead indicated by the triggering includes the embedded optical transmission.
  • the overhead indication signal may be a 7-bit signal, each bit representing one of PM-STAT and 6 TCMn-STATs (1 ⁇ 6), the bit value indicating the PM-STAT or TCMn-STAT overhead represented by the bit Whether the value can be modified, such as 0 can be modified, 1 can not be modified.
  • the modified duration signal can also be used as a parameter set by the network management system.
  • the control unit can be set to the longest service short-time that may be caused when the embedded subnet is protected and switched.
  • the ODU layer failure indication signal indicates that the ODU layer has become invalid and the failure persists
  • the modification duration is not reached
  • the above-mentioned 7-bit overhead indication signal is output as the modification indication signal, and in other cases, the all-one 7-bit signal is output, wherein the bit value of 0 indicates that the overhead represented by the bit is to be modified, and is 1 Indicates that the overhead represented by this bit is not modified.
  • the present invention is not limited thereto, and the function of modifying the control unit may be implemented by software or other hardware structure.
  • the modification control unit notifies the cost modification unit to cancel the modification after the modification for a period of time, and may be: the modification control unit notifies the cost modification unit to cancel the modification when the set modification duration expires; or, the modification control When the set modification duration expires, if the ODU layer has not returned to normal, the notification modification unit cancels the modification, and within the set modification duration, if the ODU layer returns to normal, immediately notify the overhead modification unit to cancel the modification. .
  • a switching detection unit may be added to the overhead modification device of the embodiment, such as adding a hardware detection circuit for After the ODU layer failure indication signal indicates that the ODU layer becomes invalid, it is detected whether the fault can be recovered by the protection switching system of the embedded optical transmission subnet and notified to modify the control unit, and accordingly, the modification control unit is further used to invalidate in the ODU layer. If the duration of the modification does not reach the set modification duration, it is known that the fault cannot be recovered by the protection switching system of the embedded optical transmission subnet, and the output indicates that the modified modification indication signal is cancelled. After the above improvement, in the case that the embedded subnet protection switching fails, the protection switching delay of the jacket subnet caused by the modification duration can be reduced to a minimum.
  • the embodiment further provides a network element for embedding an optical transmission subnet, which includes the overhead modification device 21 and the ODU layer failure processing device 22 based on the ODU layer failure detection provided in this embodiment, as shown in FIG. 13, the ODU layer.
  • the failure handling device 22 includes:
  • the ODU layer failure detecting unit 221 is configured to detect, according to the ODU overhead in the ODUi signal, whether the ODU layer is invalid, and output an ODU layer failure indication signal.
  • the selection unit 222 is a 2-to-1 selector for outputting an ODUi signal when the ODU layer failure indication signal indicates that the ODU layer is normal.
  • the output is from the overhead modification device.
  • the structure of the ODU layer failure processing device and the position in the network element are the same as those of the existing ODU layer failure processing device, except that the original input signal ODUi-AIS becomes an unmodified or modified ODUi outputted by the overhead modification device. AIS signal.
  • the overhead indication signal and the modification duration of the modified control unit are set according to the innermost embedded optical transport subnet to which the network element belongs.
  • the optical transport subnet C is nested in the optical transport subnet B
  • the optical transport subnet B is nested in the optical transport subnet A
  • the NE is configured to set the optical subnet B according to the embedded subnet.
  • the parameters are set according to the embedded subnet as the innermost optical transport subnet C.
  • the normal ODUi signal is output when the ODU layer fails, and the modified ODUi-AIS signal is inserted if the ODU layer becomes invalid, and the modified ODUi-AIS signal duration does not exceed the set modification duration. Therefore, temporarily buffering the output information of the output to the downstream network element triggers the jacket subnet protection switching.
  • Embodiment 2 The cost modification method based on the failure of the ODU layer needs to be used for all network elements embedded in the optical transport network, because the method is applied to only one network element, such as a network element that performs the embedded optical transport subnet protection switching handover. After the upstream network component that detects the fault is inserted into the ODUi-AIS to replace the failed ODUi, the network element considers that the ODUi signal transmitted by the upstream network element is a normal signal, so that no cost modification is performed, which is cumbersome to implement.
  • the embodiment of the present invention provides a method for modifying the cost of the failure detection based on the TCM layer, which is applied to the network element that performs protection switching in the embedded optical transport subnet. As shown in FIG. 14, the method includes:
  • Step 310 The TCM layer detected when the protection switching process is performed in the embedded optical transmission subnet is detected to be invalid according to the ODUi signal before the ODU layer failure processing.
  • the ODU layer failure handling here can use the method in the existing standard to insert an ODUi-AIS signal for replacing the failed ODUi signal when the ODU layer fails.
  • Each TCMn-STAT overhead constitutes a TCM layer, l ⁇ n ⁇ 6, and the TCM layer becomes invalid.
  • the value of the TCM layer triggers the embedded optical transport subnet protection switching, for example, detecting a symbol.
  • the TCM layer is considered to be invalid by one or more of the following conditions:
  • the service layer of the TCM layer becomes invalid
  • the TCM layer becomes AIS, Connection Lock Indication (LCK), Connection Disconnect Indication (OCI), or Serial Loss (LTC) status.
  • AIS Connection Lock Indication
  • OCI Connection Disconnect Indication
  • LTC Serial Loss
  • Step 320 The normal ODUi signal outputted after the ODU layer is invalidated or inserted
  • the value of the overhead of the jacket subnet protection switching in the ODUi-AIS signal is modified to not trigger the value of the jacket subnet protection switching, and the modification does not trigger the inline optical transmission subnet protection switching.
  • the jacket subnet, the cost of triggering the jacket subnet protection switching, the overhead of triggering the embedded optical transmission subnet protection switching, and the value of not triggering the jacket subnet protection switching are the same as in the second embodiment. See the instructions under step 220.
  • Step 330 in the set modification duration, if it is detected that the TCM layer is restored to normal, step 340 is performed, otherwise, step 350 is performed;
  • the duration of the above modification is determined by the longest service momentary time that may be caused by the protection switching of the embedded subnet, such as the longest service momentary time.
  • Step 340 cancel the modification, and end.
  • Step 350 When the set modification duration expires, the modification is cancelled and the process ends.
  • the network element applying the above method may belong to multiple embedded optical transport subnets at the same time.
  • the embedded optical transport subnet in the above method refers to the network.
  • the above method may also add a process of canceling the modification immediately if the TCM layer failure cannot be recovered by the protection switching system of the embedded optical transmission subnet within the set modification duration.
  • the network element After the network element detects that the ODU layer is invalid, the network element temporarily masks the cost information of the subnet protection switching that is triggered by the network element, so that the network element in the jacket subnet cannot be perceived.
  • the business network is interrupted during the protection switching by the embedded network element.
  • the embodiment provides an overhead modification apparatus 31, which is applied to a network element that performs the embedded optical transmission subnet protection switching handover in the embedded optical transmission subnet, as shown in FIG.
  • the cost modifying device 31 includes:
  • the TCM layer failure detecting unit 311 is configured to detect a TCM layer specified in the ODUi signal before the ODU layer failure processing, and output a TCM layer failure indication signal indicating whether the TCM layer is valid, where the designated TCM layer is input.
  • the TCM layer indication signal indicates a TCM layer detected when the protection switching process is performed in the embedded optical transmission subnet.
  • the modification control unit 312 is configured to output a modification indication signal according to the input TCM layer failure indication signal, an overhead indication signal for indicating whether the overhead can be modified, and the set modification duration signal, where the modification indication signal is at the TCM layer
  • the failure indication signal indicates that the TCM layer becomes invalid, indicating that the modification indicated by the overhead indication signal is modifiable may trigger the overhead of the corresponding jacket subnet protection switching and the modification is indicated by the overhead indication signal as being unmodifiable, the embedded light is triggered.
  • the overhead of transmitting the subnet protection switching, and after the modification continues for a period of time, notifying the overhead modification unit to cancel the modification, and the period of time is less than or equal to the set modification duration.
  • the cost modifying unit 313 is configured to modify, according to the indication of the modification indication signal, the value of the overhead of triggering the corresponding jacket subnet protection switching in the normal ODUi signal or the inserted ODUi-AIS signal outputted after the ODU layer is invalidated.
  • the value of the jacket subnet protection switching is triggered, and the modification does not modify the overhead of the embedded optical transmission subnet protection switching, and then outputs; and cancels the modification according to the indication of the modification indication signal.
  • the TCM layer detected when performing the protection switching process is one of 6 TCMns, and the TCM layer indication signal may be a 6-bit signal, wherein only one bit value indicates that the TCM layer represented by the bit needs to be detected, that is, only one is detected.
  • the overhead of the TCM layer which specifically detects which TCM layer overhead can be set by the network management software. The method of TCM layer failure detection is described in step 310 of the method of this embodiment.
  • the modification control unit 312 and the configuration of the modification control unit 211 of the second embodiment, the format of the overhead indication signal and the modification indication signal, and the control logic may be the same, and are not described again. The difference is only the failure indication signal received by the two, indicating whether the ODU layer is The failure and the other is to indicate whether the TCM layer has failed.
  • the modification control unit 312 notifies the cost modification unit 313 to cancel the modification after the modification is continued for a period of time, and may be: the modification control unit 312 notifies the cost modification unit 313 to cancel the modification when the set modification duration expires; or, the modification control When the set modification duration expires, the TCM layer has not returned to normal, and the notification overhead modification unit 313 cancels the modification, and The set modification duration, such as the TCM layer returns to normal, immediately notify the cost modification unit
  • the overhead to be modified by the overhead modification unit 313 is the same as that of the second embodiment, and is also a partial overhead in the PM-STAT overhead and the six TCMn-STAT overheads, but the modified signal may be an ODU layer in addition to the inserted ODUi-AIS.
  • a switching detection unit may be added to the overhead modifying device 31 of the embodiment, such as adding a hardware detecting circuit for detecting after the TCM layer failure indication signal indicates that the TCM layer becomes invalid. Whether the fault can be recovered by the protection switching system of the embedded optical transmission subnet and notified to the modification control unit, and correspondingly, the modification control unit 312 is further configured to know that the duration of the failure of the TCM layer does not reach the set modification duration. When the fault cannot be recovered by the protection switching system of the embedded optical transmission subnet, the output instruction cancels the modified modification indication signal.
  • the embodiment further provides a network element for performing the embedded optical transmission subnet protection switching handover in the embedded optical transmission subnet, which includes the overhead modification device 31 and the ODU layer failure based on the TCM layer failure detection provided in this embodiment.
  • the processing device 32 as shown in FIG. 15, the ODU layer failure processing device 32 includes an ODU layer failure detecting unit 321 and a selecting unit 322, configured to output a normal ODUi signal when the ODU layer is normal, and output when the ODU layer fails. An ODUi-AIS signal inserted to replace the failed ODUi signal.
  • the structure of the ODU layer failure processing device 32 of the present embodiment, the position in the network element, and the input signal can be the same as those of the existing ODU layer failure processing device. If the network element belongs to multiple embedded optical transmission subnets at the same time, the overhead indication signal and the modification duration of the modified control unit are in accordance with the innermost embedded optical transmitter of the plurality of embedded optical transmission subnets to which the network element belongs. Network settings.
  • the network element performing the embedded optical transmission subnet protection switching switching in the embedded optical transmission subnet may be configured to modify the ODU layer failure processing after detecting that the TCM layer becomes invalid according to the TCM layer failure detection result.
  • the normal ODUi signal or the inserted ODUi-AIS signal triggers the overhead of the corresponding jacket subnet protection switching, and the duration of the modification of the signal does not exceed the set modification duration, thereby temporarily masking the network element output.
  • the embodiment provides a method for preventing simultaneous nesting of multiple subnets, and the applied network Including a pair of subnets with protection switching function and directly nested, the embedded subnet and the outer subnet in the pair of subnets are optical transmission subnets, FIG. 3 is an example of such a network, and FIG. 16 shows an example. Another example of such a network, there is also the problem that the jacket subnet and the embedded subnet may simultaneously have protection switching or protection switching timeout.
  • All the network elements of the embedded subnet perform the overhead ⁇ ⁇ tampering method based on the ODU layer failure detection provided in the second embodiment;
  • the network element in the jacket subnet that does not belong to the embedded subnet, it can be based on existing standards.
  • the network consisting of the subnets also includes inner jacket subnets (ie, both embedded subnets and jacket subnets).
  • the network element that performs the protection switching switch in the jacket subnet includes the network element that performs the inner layer outer layer protection switching switching.
  • the network element performing the protection switching switch in the jacket subnet may not support setting the protection switching delay trigger time (no delay trigger), or setting the protection switching delay trigger time to 0, and the fault will immediately trigger the jacket.
  • the protection of the network is reversed, and the jacket subnet does not need to modify the setting of Th according to whether the embedded subnet has protection switching and the maximum service short-time caused by its protection switching, and the maintenance workload will be greatly reduced.
  • the protection switching delay trigger time can also be set to a non-zero value of less than or equal to 5 ms, and these examples can further avoid the protection switching timeout caused by the failure.
  • the embodiment further provides a network including a pair of subnets having a protection switching function and directly nested, and the embedded subnet and the outer subnet in the pair of subnets are optical transmission subnets, wherein : All the network elements in the embedded subnet use the network element of the embedded optical transmission subnet provided by the second embodiment, and the overhead modification device based on the ODU layer failure detection;
  • the protection switching delay triggering time set by the network element performing protection switching switching in the jacket subnet is smaller than the longest service interruption time that may be caused when the protection switching occurs in the corresponding embedded subnet.
  • the network element that performs the protection switching switch in the outer subnet includes the network element that performs the inner layer outer subnet protection switching.
  • the network element performing protection switching switching in the jacket subnet may not support setting the protection switching delay triggering time, or setting the protection switching delay triggering time to 0, or setting the protection switching delay triggering time to 5 ms or less. Non-zero value.
  • the optical transmission subnet A and the optical transmission subnet B having two direct nesting relationships and having protection functions are included, and the optical transmission subnet B is embedded in the optical transmission subnet A, that is, All network elements of network B are on the working or protection path of subnet A.
  • the optical transmission subnet A uses TCMa (l ⁇ a ⁇ 6) as the subnet protection switching judgment basis
  • the optical transmission subnet B uses TCMb (l ⁇ b ⁇ 6) as the subnet protection switching judgment basis, according to the optical transmission network.
  • the TCM implementation principle, a - is not equal to b, in order to achieve the desired effect of the present invention, the cost modification method based on the ODU layer failure detection of the second embodiment is applied to all the network elements in the embedded subnet B, and the TCMa- is set.
  • the STAT overhead is a modifiable overhead
  • the TCMb-STAT overhead is an unmodifiable overhead.
  • the bit representing the TCMa-STAT overhead in the configuration overhead modification indication signal is 0, the bit representing the TCMb-STAT overhead is 1, and the remaining bits can be arbitrarily set.
  • the modification duration of the TCMa-STAT overhead can be set to the maximum service interruption time that can be caused by the protection switching in the embedded subnet B. All NEs in subnet B that are not subnet B can be based on the existing optical transport network standard, and the NE setting in the subnet A that performs the protection switching function is 0.
  • the network element in the subnet B detects that the ODU layer is invalid.
  • the TCMb-STAT cost of the ODUi-AIS is TCMb-based after the cost modification method based on the ODU layer failure detection in the second embodiment.
  • the AIS, TCMa-STAT cost is the modified value STATt. Therefore, the subnet B can detect the service failure and trigger the protection switching.
  • the subnet A detects that the TCMa-STAT cost is STATt. Therefore, protection switching does not occur. This prevents the protection switching system of subnet A and subnet B from being switched at the same time. If subnet B Because the accident did not protect the switching success, resulting in business interruption, due to
  • the modification of the TCMa-STAT cost will only last for a period of time. After the modification duration expires, the TCMa-STAT cost will be TCMa-AIS. At this time, the subnet A will undergo protection switching, which will obviously extend the subnet A. The service transient time caused by the protection switching, but the probability of a protection switching failure on the subnet B is very low.
  • three optical transmission subnets A, B, and C each having a protection switching function have a nesting relationship, in which an optical transmission subnet B is embedded in the optical transmission subnet A, That is, all the network elements of the subnet B are in the working or protection path of the subnet A, and the optical transmission subnet C is embedded in the optical transmission subnet B, that is, all the network elements of the subnet C are working in the subnet B or On the protection path.
  • the optical transmission subnet A uses TCMa as the subnet protection switching judgment basis
  • the optical transmission subnet B uses TCMb as the subnet protection switching judgment basis
  • the optical transmission subnet C uses TCMc as the subnet protection switching judgment basis (a ⁇ b ⁇ c, l ⁇ a ⁇ 6, l ⁇ b ⁇ 6, l ⁇ c ⁇ 6)
  • On all NEs in subnet C set the TCMa-STAT overhead and TCMb-STAT overhead to be modifiable.
  • the TCMc-STAT cost is unmodifiable.
  • the duration of the modification overhead is protected by the embedded subnet C.
  • the longest business momentary time may be determined.
  • the TCMa-STAT overhead is set to a modifiable overhead
  • the TCMb-STAT overhead is an unmodifiable overhead.
  • the duration of the modification overhead occurs from the embedded subnet B.
  • the longest business momentary time decision that can be caused by protection switching. All network elements in the jacket subnet A that do not belong to subnet B can be based on existing optical transport network standards.
  • the NEs that perform subnet A and subnet B protection switching are set to Th.
  • the embodiment can implement protection switching without affecting each other in a case where a maximum of six optical transmission subnets with protection switching functions are nested layer by layer.
  • the network of the application is the same as that of the fourth embodiment. Referring to FIG. 3 and FIG. 16, a pair of subnets having a protection switching function and directly nested are included, and the embedded subnet and the outer subnet in the pair of subnets are all optically transmitted. Subnet.
  • the network element performing the embedded optical transport subnet protection switching in the embedded subnet performs the overhead modification method based on the TCM layer failure detection provided by the third embodiment
  • the network element performing the protection switching handover in the outer subnet further includes a network element performing the inner layer outer layer protection switching switching, and the embedded In the subnet (which may include the embedded subnet), in each optical transport subnet with the protection switching function of the embedded subnet and the outer subnet, the optical element performing the optical transport subnet protection switching is performed.
  • the overhead modification method based on the TCM layer failure detection provided in Embodiment 3 and the embedded optical transmission subnet in the overhead modification method refers to the optical transmission subnet.
  • the embodiment only needs to be executed on a small number of network elements, and the fourth embodiment needs to be executed on more network elements, and the cost is different.
  • the TCMn-STAT overhead allocated to the jacket subnet can be modified after the failure of the specified TCM layer is detected.
  • the NE in the jacket subnet may have detected a short TCM-AIS state and trigger protection switching. Therefore, the network element performing protection switching switching in the jacket subnet can set a short protection switching delay trigger time Th, and the value of Th is greater than or equal to the time required to complete the overhead modification and is less than or equal to 10 ms (enough to complete the modification), so that the embedded The network element of the subnet does not perform protection switching until the modification is completed.
  • the time required to complete the modification can be obtained through estimation or testing.
  • the specific value can be set according to the actual network condition, for example, set to 5ms.
  • the embodiment further provides a network including a pair of subnets having a protection switching function and directly nested, and the embedded subnet and the outer subnet in the pair of subnets are optical transmission subnets, wherein
  • the network elements that perform the embedded subnet protection switching in the embedded subnet are provided in Embodiment 3.
  • the protection switching delay triggering time set by the network element performing protection switching switching in the jacket subnet is smaller than the longest service interruption time that may be caused when the protection switching occurs in the corresponding embedded subnet.
  • the above embedded subnets can no longer be embedded with other optical transport subnets.
  • the network element performing the protection switching handover in the outer subnet further includes a network element performing the inner layer outer layer protection switching switching, and the embedded
  • the network element that performs the optical transport subnet protection switching handover uses the network of the embedded optical transport subnet provided in the third embodiment.
  • the overhead modification device based on the TCM layer failure detection processes the optical transmission subnet as an embedded optical transmission subnet.
  • This embodiment is similar to the processing in the fourth embodiment when the fault occurs, but in this embodiment, the network element performing the jacket subnet protection switching switching in the jacket subnet performs the TCM layer failure detection, and the detection is performed.
  • the processing of the overhead modification and the cancellation modification after the failure is similar, and the example of the fourth embodiment can be referred to.
  • the protection switching system of multiple nested subnets in the network can be prevented from being switched at the same time, and the service caused by the protection switching is set by the prior art to set the protection switching delay triggering time to the longest service instantaneous time. Instantaneous time.
  • the set protection flapping delay trigger time is greater than or equal to the time required to complete the cost modification and is less than or equal to 10 ms, which can avoid the protection switching timeout caused by the fault.
  • the jacket subnet is a non-transport subnet, performing a network element that demaps the non-optical transport network signal from the optical transport network signal needs to be performed.
  • the OPU layer detects that if the OPU layer fails, the first non-optical transport network maintenance signal (ie, the optical transport network maintenance signal defined in the existing standard) is inserted to replace the optical transport network signal to the downstream network element.
  • the embedded subnet is used in the cost modification method provided by the second and third embodiments of the present invention. When the fault is detected, the corresponding protection of the jacket subnet is triggered, and the value of the PM-STAT overhead is modified to be PM-STATp.
  • this embodiment defines a new optical transmission network maintenance signal that does not trigger the protection switching of the non-optical transmission network element.
  • the second non-optical transport network maintenance signal is generated. After detecting the modified PM-STATp, the second non-optical transmission is generated.
  • the network maintenance signal replaces the demapped non-optical transport network signal and transmits it to the downstream network element. After receiving the maintenance signal of the second non-optical transmission network, the non-optical transmission network element identifies the normal non-optical transmission network signal and does not perform protection switching.
  • the embodiment provides a method for converting an optical transport network signal to a non-optical transport network signal, and is applied to a network element that performs signal processing for de-mapping a non-optical transport network signal from an optical transport network signal, where the network where the network element is located includes
  • the embedded optical transmission subnet and the outer non-optical transmission subnet of the direct nesting relationship are as shown in FIG. 17, and include:
  • Step 610 Detecting whether the value of the PM-STAT overhead in the ODUi signal is the value of the embedded optical transmission subnet network element that does not trigger the protection of the non-optical transmission subnet protection after the modification of the PM-STAT overhead, if If yes, go to step 620, otherwise, go to step 630;
  • the modified PM-STAT overhead does not trigger the value of the corresponding jacket subnet protection switching, such as one of three bits of 000, 010, 011, and 100.
  • Step 620 Output an inserted second non-optical transport network maintenance signal to replace the non-optical transport network signal demapped from the optical transport network signal;
  • the second non-optical transport network maintenance signal is a newly defined non-optical transport network maintenance signal that does not trigger the non-optical transport network element protection switching, that is, the PM-STAT overhead is detected to be inserted after the PM-STATp is inserted.
  • the non-optical transport network element identifies it as a normal signal and does not trigger the signal of the non-optical transport network element protection switching.
  • a signal with no data frame and all idle (IDLE) frames can be used as the second non-optical transmission.
  • the network maintenance signal for the SDH signal, the available payload area is all fixed value and the regeneration section and the multiplex section overhead are normal signals as the second non-optical transmission network maintenance signal.
  • the definition of the specific format of the second non-optical transport network maintenance signal is not limited thereto, as long as it can cause the non-optical transport network to not trigger the protection switching, the person skilled in the art can modify the maintenance of the second non-optical transport network according to the condition.
  • the definition of the specific format of the signal is not limited thereto, as long as it can cause the non-optical transport network to not trigger the protection switching, the person skilled in the art can modify the maintenance of the second non-optical transport network according to the condition.
  • the definition of the specific format of the signal is not limited thereto, as long as it can cause the non-optical transport network to not trigger the protection switching, the person skilled in the art can modify the maintenance of the second non
  • Step 630 Output a non-optical transport network signal or a first non-optical transport network maintenance signal that is demapped from the optical transport network signal according to whether the OPU layer is invalid.
  • the processing of PM-STAT overhead when non-PM-STATp is consistent with existing standards, if If the OPU layer fails, the first non-optical transport network maintenance signal is inserted to replace the non-optical transport network signal demapped from the optical transport network signal, as the output signal of the network element, otherwise the OPU is normally processed, and the optical transport network is used.
  • the signal unmapped non-optical transport network signal is used as the output signal of the network element.
  • the conversion method of the embodiment is combined with the cost modification method of the second embodiment or the third embodiment.
  • the network element of the embedded subnet detects a fault
  • the corresponding jacket subnet is protected and the corresponding subnet includes the non-optical carrier.
  • the value of the PM-STAT is modified, and the network element that demaps the signal from the optical transport network to perform non-optical transport network signal processing (either on the embedded subnet or on the outer jacket) can detect the PM.
  • the second non-optical transport network maintenance signal is inserted to avoid the non-optical transmission subnet protection switching, because the PM-STAT modification only lasts for a period of time, so that the embedded subnet can be reached.
  • the element has a protection switching but does not trigger the effect of the protection of the subnet network element protection.
  • the apparatus for converting an optical transport network signal to a non-optical transport network signal is applied to a network element that performs signal processing for de-mapping a non-optical transport network signal from an optical transport network signal, where the network where the network element is located includes direct embedding
  • the ODUi demapping unit 61 is configured to demap the non-optical transport network signal from the ODUi. Existing ODUi demapping units can be used.
  • the OPU layer failure detecting unit 62 is configured to determine whether the value of the PM-STAT overhead is equal to STATp according to the ODU and OPU layer overhead of the ODUi signal, and determine whether the OPU layer is invalid, and output a selection control signal according to the detection result.
  • the meaning of STATp is the same as above, and the determination of the failure of the OPU layer can be based on the methods in the existing standards.
  • the selecting unit 63 uses a 3-to-1 selector for selecting an output from the input non-optical transport network signal, the first non-optical transport network maintenance signal, and the second non-optical transport network maintenance signal according to the selection control signal.
  • the OPU layer failure detecting unit outputs a corresponding selection control signal according to the following manner: when detecting that the PM-STAT cost in the ODUi signal is equal to STATp, outputting a selection control signal for selecting a second non-optical transmission network maintenance signal; When the value of the PM-STAT is not equal to STATp and the OPU layer fails, the selection control signal for selecting the maintenance signal of the first non-optical transmission network is output; when the value of the PM-STAT is not equal to STATp and the OPU layer is normal, , outputting a selection control signal for selecting a non-optical transmission network signal.
  • the embodiment further provides a network element for performing demapping of the non-optical transport network signal processing from the optical transport network signal, wherein the foregoing conversion apparatus of the embodiment is included
  • the network to which the embodiment is applied includes a pair of subnets having a protection switching function and having a direct nesting relationship, wherein the embedded subnet is an optical transmission network, and the outer subnet is a non-optical transmission network.
  • Figure 5 is an example of such a network
  • Figure 19 shows another example of such a network, in which both subnet 1 and subnet 2 have a protection switching function, and the network also has a jacket subnet and an embedded subnet. At the same time, the protection switching or the protection switching timeout occurs.
  • the method for preventing simultaneous nesting of multiple subnets in this embodiment is based on the method for preventing simultaneous nesting of multiple subnets provided in Embodiment 4 or Embodiment 5, and the subnet subnet is transmitted by the optical subnet. Change to a non-optical transport subnet and add the following features:
  • Performing a method of de-mapping the non-optical transport network signal processing from the optical transport network signal performs the conversion method of the optical transport network signal provided by the sixth embodiment to the non-optical transport network signal.
  • the network of the present embodiment includes a pair of optical transmission subnets having a protection switching function and directly nested, and the jacket subnet is transmitted by the optical network based on the network provided in Embodiment 4 or Embodiment 5.
  • the subnet is changed to a non-optical transport subnet and the following features are added:
  • the network element for performing the non-optical transport network signal processing from the optical transport network signal is provided by the sixth embodiment.
  • Example 5 Compared with the network applied in Embodiment 4 and Embodiment 5, the difference in this embodiment is that the jacket subnet is a non-optical transmission network, and thus the non-optical transmission network signal needs to be demapped in performing the signal from the optical transmission network.
  • the network element is added with the conversion process of the optical transport network signal provided in Embodiment 6 to the non-optical transport network signal, so that the first non-optical transport network is not transmitted to the downstream non-optical transport network element during the modification duration of the overhead. Maintaining the signal, avoiding simultaneous switching between the optical transport network and the non-optical transport network, and avoiding the non-optical transport network protection switching delay timeout when a fault occurs in the outer subnet of the embedded subnet.
  • the embedded subnet B is an optical transmission subnet, and uses TCMb (l ⁇ b ⁇ 6) as a subnet protection.
  • the jacket subnet A is a non-optical transmission subnet
  • the protection switching condition is related to the non-optical transmission signal type processed by the non-optical transmission subnet.
  • the present invention does not care about the actual protection switching condition of the non-optical transmission subnet.
  • the PM-STAT overhead is set to a modifiable overhead
  • the TCMb-STAT overhead is an unmodifiable overhead.
  • the modification duration of the PM-STAT overhead is set to the maximum service interruption time that may occur when the protection switching occurs on the embedded subnet B.
  • the conversion method of the network element application method for de-mapping the non-optical transmission network signal processing from the optical transmission network signal is performed, and the network element setting Th in the sub-network A performing the protection switching is set to 0.
  • TCMb-STAT is TCMb-AIS and the value of PM-STAT is the value of the TCMb-STAT.
  • STATp the value of TCMb-STAT is TCMb-AIS to ensure that subnet B can be protected normally.
  • the value of PM-STAT is STATp will trigger the network to perform demapping from the optical transport network signal to non-optical transport network signal processing.
  • the network element outputs the second non-optical transport network maintenance signal, and when the subnet A detects the second non-optical transport network maintenance signal, the service is considered normal, so protection switching does not occur, so that the subnet A and the subnet B can be prevented. At the same time protect the switch.
  • the subnet B If the subnet B is successful because the accident is not protected, the service is always interrupted. Since the modification to the PM-STAT will only last for a while, the PM-STAT value is PM-AIS after the modification duration ends.
  • the protection switchover occurs. This will prolong the service interruption time caused by subnet A protection switching, but the probability of protection switching failure of subnet B occurs. very low.
  • the network element that does not belong to subnet B in subnet A fails.
  • the subnet A detects the first non-optical transport network maintenance signal, and the network element that performs the protection switchover in subnet A has set Th to 0, so the protection switching of subnet A is triggered immediately.
  • Subnet A is a non-optical transmission subnet with protection switching function.
  • Subnets B and C are optical transmission subnets, and subnet B is embedded in subnet A, subnet C. Embedded in subnet B, only subnet C in subnet B has the protection switching function. The part of subnet B that does not belong to subnet C does not have the protection switching function, that is, subnet C and subnet A are defined by the present invention.
  • the subnet C uses the TCMc (l ⁇ c ⁇ 6) as the subnet protection switching judgment basis.
  • the cost modification method of the second embodiment needs to be applied to all the network elements in the subnet C, and the network performs the optical transmission network signal.
  • Decoding the non-optical transport network signal processing network element application embodiment sixth conversion method setting the PM-STAT overhead for all network elements in the subnet C is modified for a period of time, the TCMc-STAT overhead is set to not be modified,
  • the network element that performs protection switching in subnet A can set Th to 0.
  • the protection switching of subnet C does not cause protection switching at the same time.
  • the subnet A does not have a protection switching delay timeout.
  • the cost modification method and the conversion method of the foregoing embodiments do not affect the normal operation of the network element in the network in which the foregoing embodiment is not applied.
  • Figure 20 shows the network structure corresponding to this application example.
  • all subnets are optical transport subnets, and the transmitted services are OTU2 services.
  • NEs 1 to 6 are network elements of subnet B, and network elements 1 to 10 are network elements of subnet A.
  • Subnet B is embedded in subnet A.
  • Subnet A uses TCM2 as the basis for protection switching.
  • Subnet B uses TCM1 as the basis for protection switching.
  • Network elements 1 to 6 in subnet B apply the cost modification device of the second embodiment.
  • the bit indicating the TCM1 in the overhead indication signal is 1 can not be modified, and the bit representing TCM2 is 0, which can be modified, and the remaining bits can be arbitrarily set, and the modification duration is set to 50 ms, wherein 50 ms is the subnet B transmission.
  • the longest service momentary time may be caused by the protection switching.
  • the above settings can be completed when the protection switching function of subnet B is set.
  • the network elements 4 and 10 in the subnet A are the network elements that perform protection switching, and set the protection switching delay trigger time to 0 for the above two network elements.
  • the cost modifying device in the network element 3 will enable the network element 3 to output the modified overhead ODU2-AIS for up to 50 ms, wherein the value of the TCM1-STAT overhead is TCM1- The value of AIS and TCM2-STAT is STATt.
  • NE 4 can be switched normally according to TCM1-AIS. Since NE 4 is the end point of TCM1, NE 4 The value of the TCM1-STAT in the output ODU2-AIS is TCM1-LTC, where the LTC value is 000.
  • the OTN standard specifies that the network element at the TCM endpoint needs to change the TCM-STAT value to TCM-LTC, indicating the TCM. For idle, it can be used as a starting point for TCM by other network elements. At the same time, since the network element 4 is not the starting point or the end point of the TCM2, the TCM2 overhead is transparently transmitted. Therefore, the value of the TCM2-STAT overhead in the ODU2-AIS received by the network element 10 before the protection switching occurs from the optical fiber interruption to the network element 4 It is always STATt. At this time, NE 10 considers that the service is normal and protection switching does not occur.
  • FIG. 21 is a TCM overhead state of the network elements 3, 4, and 10 before the network element 3 detects a failure to the network element 4 before the protection switching occurs.
  • Figure 22 shows the network structure corresponding to this application example.
  • the non-optical transport network elements C1 to C6 form a non-optical transport subnet with protection switching function
  • the optical transport network elements 1 to 8 form an optical transport subnet, where the network elements 1 to 6
  • the optical transmission subnet consists of a protection switching function.
  • the interface signal between the optical transmission subnet and the non-optical transmission subnet is the Ethernet signal 10GBAE-R
  • the optical transmission network element maps the 10GBASE-R to the OTU2e, and the OTU2e
  • the signal format inside the optical transport network is transmitted between the network elements of the optical transport network.
  • the network elements 1 to 6 in the optical transmission subnet apply the overhead modification apparatus of the second embodiment, and the bit representing the TCM1 in the overhead modification indication signal is 1 and cannot be modified, and the bit representing the PM is 0. Indicates that it can be modified, and the remaining bits can be set arbitrarily.
  • the modification duration is set to 50ms, of which 50ms is the network element.
  • the maximum service break time that may be caused by protection switching occurs on the subnets of 1-6. The above settings can be set when the protection functions of NEs 1 to 6 are set.
  • the network elements 1 and 4 that perform the mutual conversion between the optical transport network signal and the non-optical transport network signal apply the conversion device of the sixth embodiment, and the network elements 4 and C6 are the network elements that perform the protection switching, and set the protection switching delay trigger time. Is 0.
  • the overhead device in the network element 3 will cause the network element 3 to output the modified overhead ODU2e-AIS for up to 50 ms, wherein The value of the TCM1-STAT is TCM1-AIS, and the value of the PM-STAT is STATp.
  • the network element 4 can be switched normally according to TCM1-AIS, and the fault is detected on the network element 3. Before the meta-switching occurs, the conversion device in the network element 4 will always detect that the value of the PM-STAT overhead of the ODU2e-AIS is STATp, and the second Ethernet maintenance signal will always be output.
  • the second Ethernet maintenance signal is a 10GBASE-R format signal with no data frames and all idle frames, and C4 and C6 will always receive the second Ethernet maintenance signal, which is used for implementing the protection switching function on the C6.
  • the service failure detection circuit considers that the signal is a normal signal, so C6 does not undergo protection switching. 4: The protection switching of network element 4 is completed in t time (t ⁇ 50ms), then the fiber of network element 2 to network element 3 is interrupted. After time t, network element 4 will lose Normal 10GBASR-R signal, then the network element receives also C4 and C6 normal 10GBASE-R signal, so that the network element does not still C6 switchover, the above process to ensure only the protection switching occurs 4 NE.
  • Figure 23 shows the state of the network elements 3, 4, C4, and C6 before the network element 3 detects a fault and the protection switch occurs.
  • the protection switching delay triggering time th of the network element C6 is greater than that of the optical transmission subnet protection switching. In the case of a short-lived time, the protection of the subnet C6 does not occur during the protection switching of the subnet consisting of the network element 1-6.
  • the time for the service interruption of the optical transmission subnet protection switching is generally 50 ms, in order to leave a margin.
  • the Th of the network elements C3 and C6 is set to 100mSo. If the fiber between the network element C1 and the network element 1 is interrupted, as shown in Figure 24, the network element 1 will detect the 10GBASE-R failure and use the first Ethernet.
  • the network maintenance signal replaces the failed signal and continues processing.
  • the 10GBASE-R Ethernet maintenance signal is the Local Fault OrderSet
  • the network element 1 will output the normal OTU2e signal, but the payload in the OPU2e is the Local Fault OrderSet.
  • the network element 4 does not detect the failure of the TCM1 layer, so the protection switching will not be triggered, so that the network element 4 will output the Local Fault OrderSet, and the network elements C4 and C6 will receive the Local Fault OrderSet, the network element.
  • C6 considers that the Local Fault OrderSet represents the failure of the Ethernet service. However, because the Th is set, the protection fault is triggered only after the Local Fault OrderSet is detected for a period of time.
  • the service of the network element C6 needs 100ms plus the service switching time to restore normal.
  • the network elements 1 to 6 do not detect the ODU layer failure, the ODU2e-AIS or the modified overhead ODU2e-AIS is not inserted, and the protection switching is not triggered.
  • the cost modification device of the embodiment will obtain the same processing result as the corresponding device conforming to the optical transport network standard, and the network elements C4 and C6 will detect the Local Fault OrderSet immediately after the fiber break between the network element C3 and the network element 1. Since the Th of C3 and C6 has been set to 0, the protection switching occurs immediately after the network element C6 detects the Local Fault OrderSet, so that the service interruption time is the above switching service time.
  • protection switching can be performed only on the subnet where protection switching should occur, and other subnets that should not undergo protection switching do not undergo switching.
  • the protection switching system of all subnets works normally and any single point of failure occurs, the protection switching delay of the subnet with protection switching function is shortened.
  • each module/unit in the foregoing embodiment may be implemented in the form of hardware, or may use software functions.
  • the form of the module is implemented. The invention is not limited to any specific form of combination of hardware and software.
  • the switching delay triggering time Th can be set to a short value, such as a non-zero value of 0 or less than 10ms.
  • Th can be configured uniformly, reducing the workload of the configuration.

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Abstract

开销修改及防止子网同时倒换的方法及装置、网元和网络，该开销修改方法包括：检测到有故障发生，且该故障会触发该内嵌光传送子网及其外套子网保护倒换；将要传送到下游网元的信号中会触发外套子网保护倒换的开销的取值修改为不会触发外套子网保护倒换的取值；修改持续一段时间后，取消修改，该段时间小于等于设定的修改持续时间。嵌套的多个子网中的内嵌子网的网元执行上述开销修改方法，同时设置外套子网中执行保护倒换切换的网元的保护倒换延迟触发时间小于该内嵌子网发生保护倒换时可能引起的最长业务瞬断时间，从而可以避免子网同时倒换，并缩短内嵌子网外外套子网内故障引起的保护倒换延迟。本申请还提供了相应的装置、网元和网络。

Description

开销修改及防止子网同时倒换的方法、 装置、 网元和网络
技术领域
本发明涉及通信领域的传输设备和光传送网领域， 尤其涉及一种开销修 改及防止子网同时倒换的方法、 装置、 网元和网络。
背景技术
光传送网（ OTN, Optical Transport Network )标准由国际电信联盟（ ITU-T ) 制定， 是传输设备的重要标准， 现在几乎所有的长距传输网络都由基于光传 送网标准的设备组成。
光传送网有其标准的信号格式， 称为 ODUi信号 (i=0,l,2,3,4,2e,3e,flex) ( ODU: Optical channel Data Unit, 光通道数据单元） ， 光传送网内部只处 理 ODUi信号， 需要被光传送网传输的各种非光传送网信号在进入光传送网 的接入点时就会被转换为合适的 ODUi信号， 以后 ODUi信号在光传送网中 传送， 直到达到目的点后从 ODUi中解映射出各种非光传送网信号， 从而实 现各种非光传送网信号在光传送网上的接入点和目的地之间的传送。 ODUi 只能在光传送网设备内部存在， 如果要在光传送网设备之间传送则必须将其 转换为 OTUk ( k=l,2,3,4,2e,3e ) ( OUT: Optical Transform Unit, 光转化 单元） ， 一般来说多个 ODUi会被复用到一个 OTUk中传送， 以提高传送效 率， ODUi和 OTUk都是光传送网信号。 ODUi和 OTUk的定义来自 ITU-T G.709标准。
光传送网是传输距离最长的网络， 其网络结构相对于其他通讯网络来说 也是最复杂的。 在光传送网中， 处理光传送网信号的站点叫做网元， 多个网 元通过光传送网信号 OTUk连接起来组成子网 （文中称为光传送子网） ， 一 个光传送网一般由多个子网组成， 每个子网可能属于不同设备商或运营商的 设备， 同一个设备商或运营商的设备也可能根据地域关系划分为多个子网， 光传送网可以实现基于子网的保护倒换， 当多个子网同时具备保护倒换功能 时， 根据现有的光传送网实现技术， 只要同时具备保护倒换功能的子网之间 没有嵌套关系， 则每个子网的保护倒换不会影响其他子网， 下面举例说明。 图 1示出了以串联方式连接的具备保护倒换功能的两个光传送子网， 其 中网元 1至 6组成一个具备 1+1保护倒换功能的子网 A,其中网元 1 , 2, 3 , 4为工作路径， 网元 1 , 5, 6, 4为保护路径； 网元 7至 12组成一个具备 1+1 保护倒换功能的子网 B, 其中网元 7, 8, 9, 10为工作路径， 网元 7, 11 , 12, 10为保护路径， 为了描述方便， 假设所有业务方向都是单向的， 方向如 图中箭头所示， 实际上两个相反方向的单向子网即可组成一个双向子网， 所 以本文虽然用单向子网说明， 但结果同样适用于双向子网。
图 1中的两个子网以串联方式连接。 根据光传送网标准， 光传送网支持 子网保护倒换， 子网保护倒换通过串联连接监测 （TCM )开销实现。 TCM 开销是光传送网中定义的支持子网性能检测的开销， TCM有 6 级， 分别为 TCM1-TCM6, 经过合理划分 TCM的使用范围后， TCM可以用来单独检测 子网状态， 并排除其他子网对本子网状态的影响。 在光传送网中， 为了实现 子网保护倒换， 需要给每个支持保护倒换的子网分配一个 TCM开销， 每个 子网通过检测分给其的 TCM开销的状态判断是否需要触发保护倒换。 对于 上图中的串联子网， 可以给子网 A和子网 B都分配 TCM1开销， 图中的虚 线是 TCM开销的传递路径， TCM开销和业务一起传送， 子网 A使用 TCM1 开销作为其保护倒换判断依据， TCM1的起点为网元 1终点为网元 4,子网 B 也使用 TCM1作为其保护倒换判断依据， TCM1的起点为网元 7终点为网元 10, 这样上图中的网元 4和网元 10都根据 TCM1开销的状态判断是否应该 保护倒换。
假设子网 A内部网元 2到网元 3之间的光纤中断，如图 2中的叉号所示， 网元 3检测到 ODU层失效后会将失效的 ODUi信号替换为 ODUi-AIS信号 (AIS: Alarm Indication Signal, 告警指示信号）， ODUi-AIS是光传送网标准 定义的光传送网信号的维护信号， 其中的 TCM1-STAT开销的值为 111时表 示处于 TCM1-AIS状态。 网元 4接收到网元 3发来的 ODUi-AIS后， 通过检 测 TCM1-STAT开销发现 TCM1-STAT处于 TCM1-AIS状态， 此时认为业务 失效， 网元 4会启动保护倒换， 在保护倒换没有正式生效前会透传网元 3发 来的 ODUi-AIS信号， 由于网元 4是 TCM1的终点， 所以网元 4会将其输出 的 ODUi-AIS中的 TCM1-STAT开销改为 TCM1-LTC状态，表示 TCM1开销 资源已被释放。 网元 4发出的 ODUi-AIS传送到子网 B的网元 7后， 由于网 元 7 是 TCM1 的起点， 会将接收到的 ODUi-AIS 中的 TCM1 开销被改为 TCM1 -NORMAL状态， 以后网元 8和 9透传 ODUi-AIS,这样下游的网元 10 从网元 9接收到的 TCM1-STAT开销都显示为 TCM1-NORMAL状态， 网元 10认为 TCM1正常， 所以网元 10接收到网元 4送来的 ODUi-AIS时不会发 生保护倒换。以后网元 4发生倒换并倒换到网元 6,业务恢复正常， ODUi-AIS 消失， 在以上整个过程中子网 B中的网元 10会始终检测 TCM1 , 并会发现 TCM1始终正常， 所以网元 10会一直不倒换，这样网元 4发生倒换不会导致 网元 10倒换， 从而使得两个子网之间的保护倒换不会相互影响。
根据以上分析， 光传送网中利用现有的基于 TCM的子网保护技术可保 证两个有串联连接关系的子网的保护倒换不会互相影响。
但是， 当均具备保护倒换功能的两个子网 （或称一对子网）具有嵌套关 系时， 这两个子网的保护倒换系统也具有嵌套关系， 内嵌于另一子网中的子 网 （文中称为内嵌子网） 的保护倒换动作很可能会导致其中嵌入有该子网的 子网 （文中称为外套子网）保护倒换误触发或保护倒换超时。 文中所称的具 有嵌套关系的内嵌子网和对应的外套子网， 指该内嵌子网中的所有网元都位 于该外套子网中的工作或保护路径上 （但不同时位于工作和保护路径上） 。 一个内嵌子网对应的外套子网指其中嵌入有该内嵌子网的所有外套子网， 可 以有一个或多个， 一个外套子网对应的内嵌子网指嵌入于该外套子网中的所 有内嵌子网， 可以有一个或多个， 即子网间的嵌套可以是三个或三个以上子 网间的多层嵌套。 具有嵌套关系且具备保护倒换功能的一对子网之间可以是 直接嵌套， 也可以是间接嵌套， 所谓直接嵌套的一对子网是指该一对子网之 间不存在其他具备保护倒换功能的子网，如图 3中的子网 A和子网 B。另外， 本发明涉及的网络中， 内嵌子网或同时作为外套子网和内嵌子网的子网均为 光传送子网， 只有最外层的一个外套子网可以是非光传送子网， 或者是光传 送子网。
下面分析嵌套连接方式下两个子网的保护倒换为什么会相互影响。
图 3示出的具有嵌套关系的子网均为光传送网， 其中， 网元 1至 6组成 一个具备 1+1保护倒换功能的子网 B, 其中网元 1 , 2, 3 , 4为工作路径， 网 元 1 , 5 , 6, 4为保护路径， 图中的虚线是 TCM1 开销的传递路径， TCM1 开销在子网 B内有效， 起点为网元 1终点为网元 4, 和业务一起传送， 子网 B根据 TCM1的状态决定是否保护倒换；网元 1-10组成一个具备 1+1保护倒 换功能的子网 A, 其中网元 7 , 1 , 2 , 3 , 4 , 10为工作路径， 网元 7 , 8 , 9, 10为保护路径， 图中的虚线是 TCM2开销的传递路径， TCM2开销在子网 A 内有效， 起点为网元 7终点为网元 10, 和业务一起传送， 子网 A根据 TCM2 的状态决定是否保护倒换。子网 B嵌入在子网 A的网元 1和 4之间，是内嵌 子网， 子网 A是外套子网。 在图 3所示的环境中， 子网 A和 B必须使用不 同的 TCM开销才能保证各子网可以检测到自己子网的工作状态。
假设网元 2和网元 3 之间的光纤中断， 如图 4中的叉号所示， 网元 3会 将失效的 ODUi 信号替换为 ODUi-AIS , 其中的 TCM1-STAT 开销和 TCM2-STAT开销均处于 TCM1-AIS状态。 网元 4通过检测网元 3送来的 TCM1-STAT开销发现其处于 TCM1-AIS状态则认为业务失效， 此时网元 4 会启动保护倒换，在保护倒换没有正式生效前会透传网元 3发来的 ODUi-AIS 信号， 由于网元 4不是 TCM2的起点， 所以此 ODUi-AIS中的 TCM2-STAT 开销会被透传， 此 ODUi-AIS传送到子网 A的网元 10后， 网元 10接收到的 TCM2-START开销也显示为 TCM2-AIS状态， 此时网元 10认为业务失效， 会触发保护倒换且倒换经过网元 8和 9的保护路径上， 这样网元 A和网元 B 的保护倒换系统将基本同时启动， 相当于一点故障触发了同一条路径上的两 个不同的保护倒换系统的保护倒换动作， 这样容易导致保护倒换系统动作造 成的业务瞬断时间变长， 严重时甚至可能导致保护倒换系统倒换超时。
对于该问题， 解决方案有两种， 方案一是忽略这种两个保护系统同时保 护倒换的现象，不做任何补救措施，当嵌套现象非常严重时方案一将不可行。 方案二是如果保护倒换系统没有发生嵌套， 如内嵌子网不支持保护倒换， 则 对应的外套子网的网元可以不支持 Th设置或将 Th设置为 0。 如果保护倒换 系统发生嵌套， 在外套子网中执行保护倒换切换的网元上（如图 3中的网元 10 )设置保护倒换延迟触发时间 Th ( h=Hold off ) , 如设置为内嵌子网保护 倒换可能造成的最长业务瞬断时间。该执行保护倒换切换的网元认为持续 Th 时间以内的业务失效为正常， 不会触发保护倒换， 只有当业务失效持续时间 超过 Th后才会启动保护倒换。 方案 2虽然能保证内嵌子网内部发生故障时 保护倒换只触发一次且保护倒换时间不会超时， 但如果故障点发生在外套子 网内和内嵌子网夕卜，例如网元 4到网元 10之间的光纤连接发生中断， 由于网 元 10的 Th的存在，会导致保护倒换造成的业务瞬断时间一定大于 Th。另外， 外套子网中执行保护倒换切换的网元需要根据内嵌子网是否支持保护倒换而 对 Th做不同的设置， 会增加人工维护的工作量。 对于一个光传送子网嵌套于一非光传送子网之中的情况， 图 5给出了一 个示例。图 5中非光传送网网元 C1至 C6及 1至 8组成一个具备保护倒换功 能的非光传送子网， 光传送网网元 1至 8组成两个光传送子网， 其中由网元 1至 6组成的光传送子网具备保护倒换功能。 光传送子网和非光传送子网之 间的接口信号为以太网信号（例如 IEEE802.3定义的 10GBASE-R ) , 光传送 网内部的信号为光传送网信号（例如 OTU2e )。此网络拓朴结构实际和图 3 所 示的两个以嵌套方式连接的具备保护倒换功能的光传送子网一样， 只是图 3 中有嵌套关系的子网都是光传送子网， 属于同一层设备， 而图 5是光传送子 网嵌套于非光传送子网中， 是不同层的设备。 图 5的网络和图 3有一样的问 题， 当图 5中网元 2和 3之间的光纤中断， 内嵌的光传送网发生保护倒换， 网元 4和 C4之间会有一个以太网业务瞬断， 为了不触发以太网设备的保护 倒换， 网元 C6需要设置 Th, Th值大于光传送子网发生保护倒换时可能造成 的最长业务瞬断时间（按照光传送网的标准这个值是 50ms ) , 常见的以太网 设备会默认设置 Th为 100ms, 这样可以避免光传送网发生保护倒换时以太 网设备同时倒换。但如果非光传送网设备为 PTN设备， 其功能和传统的以太 网设备相似， 但同时具备传输设备的可靠性和保护倒换时间的要求， 其要求 的保护倒换时间和光传送网一样， 此时如果也设置 Th为光传送网的保护倒 换时间， 则和图 4类似， 当网元 4到 C4或网元 C1到网元 1出现光纤中断且 工作通道在 C1到 C4的路径上时，非光传送子网的保护倒换时间会大于 Th, 这将超过 PTN设备允许的最长保护倒换时间。另外同样会增加人工维护的工 作量。
发明内容 本发明要解决的技术问题是提供一种可以暂时屏蔽掉输出给下游网元的 会触发外套子网保护倒换的开销信息的开销修改方法及相应的开销修改装置 和网元。
为了解决上述技术问题， 本发明提供了一种开销修改方法， 应用于内嵌 光传送子网的网元中， 该方法包括： 检测到有故障发生， 且该故障会触发该 内嵌光传送子网及其中嵌入有该内嵌光传送子网且具有保护倒换功能的外套 子网保护倒换； 将要传送到下游网元的信号中会触发所述外套子网保护倒换 的开销的取值修改为不会触发所述外套子网保护倒换的取值， 且不修改会触 发该内嵌光传送子网保护倒换的开销； 所述修改持续一段时间后， 取消所述 修改， 该段时间小于等于设定的修改持续时间。
优选地， 所述开销修改方法应用于该内嵌光传送子网中的所有网元中； 所述检测到有故障发生，指检测到光通道数据单元（ ODU )层变为失效； 所述将要传送到下游网元的信号， 指插入以替换失效光通道数据单元信 号 （ODUi信号） 的 ODUi告警指示信号 （ODUi-AIS信号） 。
优选地， 所述开销修改方法应用于内嵌光传送子网中执行该内嵌光传送 子网保护倒换切换的网元中； 所述检测到有故障发生， 指根据 ODU层失效 处理前的 ODUi信号检测到该内嵌光传送子网中执行保护倒换处理时检测的 串联连接监测 （TCM )层变为失效； 所述将要传送到下游网元的信号， 指 ODU层失效处理后输出的正常的 ODUi信号或插入的 ODUi-AIS信号。
优选地， 所述会触发该内嵌光传送子网保护倒换的开销， 是分配给该内 嵌光传送子网的 TCMn-STAT开销， l≤n≤6；
所述外套子网有一个或多个， 其中最外层的外套子网为光传送子网或非 光传送子网， 如有其他外套子网， 所述其他外套子网均为光传送子网； 对其 中的一个外套子网： 如该外套子网为光传送子网， 所述会触发该外套子网保 护倒换的开销是分配给该外套子网的 TCMn-STAT开销； 如该外套子网为非 光传送子网， 所述会触发该外套子网保护倒换的开销是 PM-STAT开销。
优选地， 所述将会触发所述外套子网保护倒换的开销的取值修改为不会 触发所述外套子网保护倒换的取值， 包括： 对于为光传送子网的外套子网， 是将 TCMn-STAT开销的取值修改为 3比特的 011 , 100, 001 , 010中的一种； 对于为非光传送子网的外套子网， 是将 PM-STAT开销的取值修改为 3比特 的 000, 010, 011 , 100中的一种。
优选地， 所述设定的修改持续时间为该内嵌光传送子网发生保护倒换时 可能引起的最长业务瞬断时间。
优选地， 该内嵌光传送子网的网元只属于一个内嵌光传送子网； 或者 该内嵌光传送子网的网元同时属于多个内嵌光传送子网， 所述开销修改 方法中的该内嵌光传送子网指其中最内层的内嵌光传送子网。
优选地， 所述检测到该内嵌光传送子网中执行保护倒换处理时检测的 TCM层变为失效， 包括： 检测到符合以下条件中的一种或多种： 该 TCM层 的服务层变为失效； 该 TCM层变为 AIS、 LCK、 OCI或 LTC状态。
优选地， 所述修改持续一段时间后， 取消所述修改， 包括： 设定的修改 持续时间到时， 取消所述修改； 或者
所述修改持续一段时间后， 取消所述修改， 包括： 如设定的修改持续时 间到时 ODU层还没有恢复正常， 取消所述修改； 及在所述设定的修改持续 时间内， 如检测到 ODU层恢复正常， 立即取消所述修改。
优选地， 所述修改持续一段时间后， 取消所述修改， 包括： 设定的修改 持续时间到时， 取消所述修改； 或者
所述修改持续一段时间后， 取消所述修改， 包括： 如设定的修改持续时 间到时 TCM层还没有恢复正常， 取消所述修改； 及在所述设定的修改持续 时间内， 如检测到 TCM层恢复正常， 立即取消所述修改。
优选地， 所述修改持续一段时间后， 取消所述修改， 还包括： 在所述设 定的修改持续时间内， 如检测到故障无法被该内嵌光传送子网的保护倒换系 统恢复时， 立即取消所述修改。
相应地， 本发明提供了一种内嵌光传送子网的网元中的开销修改装置， 包括修改控制单元和开销修改单元， 其中：
所述修改控制单元， 设置为： 在检测到有故障发生时通知开销修改单元 修改开销， 其中， 该故障会触发该内嵌光传送子网及其中嵌入有该内嵌光传 送子网且具有保护倒换功能的外套子网保护倒换； 以及在修改持续一段时间 后， 通知开销修改单元取消修改， 该段时间小于等于设定的修改持续时间； 所述开销修改单元， 设置为： 在修改控制单元通知修改时， 将要传送到 下游网元的信号中会触发所述外套子网保护倒换的开销的取值修改为不会触 发所述外套子网保护倒换的取值， 且不修改会触发该内嵌光传送子网保护倒 换的开销； 以及在修改控制单元通知取消修改时， 取消所述修改。
优选地， 该开销修改装置应用于该内嵌光传送子网的所有网元中； 所述修改控制单元是设置为： 根据输入的光通道数据单元（ODU )层失 效指示信号、 用于指示开销是否可以修改的开销指示信号及设定的修改持续 时间信号， 输出修改指示信号， 其中， 该修改指示信号在 ODU层失效指示 信号指示 ODU层变为无效时， 指示修改被开销指示信号指示为可修改的会 触发对应外套子网保护倒换的开销且不修改被开销指示信号指示为不可修改 的会触发该内嵌光传送子网保护倒换的开销， 及在修改持续一段时间后， 通 知开销修改单元取消修改， 该段时间小于等于设定的修改持续时间；
所述开销修改单元是设置为： 根据所述修改指示信号的指示， 将输入的
ODUi告警指示信号（ ODUi-AIS信号）中会触发对应外套子网保护倒换的开 销的取值修改为不会触发所述外套子网保护倒换的取值且不修改会触发该内 嵌光传送子网保护倒换的开销，然后输出；及根据所述修改指示信号的指示， 取消所述修改。
优选地， 该开销修改装置应用于内嵌光传送子网中执行该内嵌光传送子 网保护倒换切换的网元中， 还包括：
串联连接监测 （TCM )层失效检测单元， 设置为： 检测 ODU层失效处 理前的 ODUi信号中指定的 TCM层，并输出指示该 TCM层是否有效的 TCM 层失效指示信号， 其中， 该指定的 TCM层是被输入的 TCM层指示信号指示 为该内嵌光传送子网中执行保护倒换处理时检测的 TCM层；
所述修改控制单元是设置为： 根据输入的 TCM层失效指示信号、 用于 指示开销是否可以修改的开销指示信号及设定的修改持续时间信号， 输出修 改指示信号， 其中， 该修改指示信号在 TCM层失效指示信号指示 TCM层变 为无效时， 指示修改被开销指示信号指示为可修改的会触发对应外套子网保 护倒换的开销且不修改被开销指示信号指示为不可修改的会触发该内嵌光传 送子网保护倒换的开销， 及在修改持续一段时间后， 通知开销修改单元取消 修改， 该段时间小于等于设定的修改持续时间；
所述开销修改单元是设置为： 根据修改指示信号的指示， 将 ODU层失 效处理后输出的正常的 ODUi信号或插入的 ODUi-AIS信号中所述会触发对 应外套子网保护倒换的开销的取值修改为不会触发所述外套子网保护倒换的 取值且不修改所述会触发该内嵌光传送子网保护倒换的开销， 然后输出； 及 根据修改指示信号的指示， 取消所述修改。
优选地， 该内嵌光传送子网网元对应的外套子网有一个或多个， 其中最 外层的外套子网为光传送子网或非光传送子网， 如有其他外套子网， 所述其 他外套子网均为光传送子网；
所述修改控制单元指示的会触发该内嵌光传送子网保护倒换的开销是分 配给该内嵌光传送子网的 TCMn-STAT开销， l≤n≤6；
所述修改控制单元指示的会触发对应外套子网保护倒换的开销， 对其中 的一个外套子网， 如该外套子网为光传送子网， 会触发该外套子网保护倒换 的开销是分配给该外套子网的 TCMn-STAT开销； 如该外套子网为非光传送 子网， 会触发该外套子网保护倒换的开销是 PM-STAT开销。
优选地， 所述开销修改单元设置为： 将所述会触发对应外套子网保护倒 换的开销的取值修改为不会触发所述外套子网保护倒换的取值， 包括：
对于为光传送子网的外套子网， 是将 TCMn-STAT开销的取值修改为 3 比特的 011 , 100, 001 , 010中的一种； 对于为非光传送子网的外套子网， 是 将 PM-STAT开销的取值修改为 3比特的 000, 010, 011 , 100中的一种。
优选地， 该内嵌光传送子网的网元只属于一个内嵌光传送子网； 或者 该内嵌光传送子网的网元同时属于多个内嵌光传送子网， 所述修改控制 单元以其中最内层的内嵌光传送子网作为控制时所基于的该内嵌光传送子网。
优选地， 所述 TCM层失效检测单元设置为： 检测到该内嵌光传送子网 中执行保护倒换处理时检测的 TCM层变为失效， 包括： 检测到符合以下条 件中的一种或多种：该 TCM层的服务层变为失效；该 TCM层变为 AIS、LCK、 OCI或 LTC状态。
优选地， 所述修改控制单元设置为： 在修改持续一段时间后， 通知开销 修改单元取消修改， 包括： 所述修改控制单元在设定的修改持续时间到时， 通知开销修改单元取消修改； 或者， 所述修改控制单元在设定的修改持续时 间到时如 ODU层或 TCM层还没有恢复正常， 通知开销修改单元取消修改； 及在所述设定的修改持续时间内， 如 ODU层或 TCM层恢复正常， 立即通知 开销修改单元取消修改； 其中， 所述设定的修改持续时间为该内嵌光传送子 网发生保护倒换时可能引起的最长业务瞬断时间。 相应地， 本发明提供的一种内嵌光传送子网的网元， 包括光通道数据单 元（ODU )层失效处理装置和开销修改装置， 其中： 所述开销修改装置釆用 本发明提供的上述基于 ODU层失效检测的开销修改装置中的一种；
所述 ODU层失效处理装置包括 ODU层失效检测单元和选择单元，其中：
ODU层失效检测单元，设置为：根据光通道数据单元信号（ODUi信号） 中的 ODU开销， 检测 ODU层是否失效， 并输出 ODU层失效指示信号到所 述开销修改装置和所述选择单元；
选择单元， 设置为： 在 ODU层失效指示信号指示 ODU层正常时， 输出 ODUi信号， 当 ODU层失效指示信号指示 ODU层失效时， 输出来自所述开 销修改装置的未经修改或修改后的 ODUi告警指示信号（ ODUi-AIS信号）。
相应地， 本发明还提供了一种内嵌光传送子网中执行该内嵌光传送子网 保护倒换切换的网元， 包括光通道数据单元（ODU )层失效处理装置和开销 修改装置， 其中： 所述开销修改装置釆用本发明上述基于 TCM层检测的开 销修改装置中的一种；
所述 ODU层失效处理装置设置为： 在 ODU层正常时， 输出正常的光通 道数据单元信号（ODUi信号）， 在 ODU层失效时， 输出插入以替换失效的 ODUi信号的 ODUi告警指示信号 （ ODUi-AIS信号） 。
上述方案可以暂时屏蔽掉输出给下游网元的会触发外套子网保护倒换的 开销信息， 避免嵌套子网同时倒换。
本发明要解决的另一技术问题是提供一种光传送网信号到非光传送网信 号的转换方法及相应的装置、 网元， 可以根据故障后对 PM层开销的修改而 屏蔽掉输出给下游网元的会触发外套子网保护倒换的维护信息。
为了解决上述技术问题， 本发明提供了一种光传送网信号到非光传送网 信号的转换方法， 应用于执行从光传送网信号中解映射出非光传送网信号的 网元中， 该网元所在网络包括具有嵌套关系的内嵌光传送子网和外套非光传 送子网， 该转换方法包括：
检测光通道数据单元信号（ODUi )中 PM-STAT开销的取值是否为该内 嵌光传送子网网元对 PM-STAT开销修改后的不会触发该外套非光传送子网 保护倒换的取值： 如果是， 输出插入的第二非光传送网维护信号以替换从光 传送网信号解映射出的非光传送网信号；如果否，根据光通道净荷单元（OPU ) 层是否失效， 输出从光传送网信号解映射出的非光传送网信号或插入的第一 非光传送网维护信号； 其中， 所述第二非光传送网维护信号是不会触发非光 传送网网元保护倒换的非光传送网维护信号， 第一非光传送网维护信号是会 触发非光传送网网元保护倒换的非光传送网维护信号。
优选地， 该内嵌光传送子网网元对 PM-STAT开销修改后的不会触发该 外套非光传送子网保护倒换的取值， 为 3比特的 000, 010, 011 , 100中的一 种。
优选地， 所述非光传送网信号是有物理编码子层 （PCS )编码的信号， 所述第二非光传送网维护信号是没有数据帧且全是空闲帧的信号； 或者 所述非光传送网信号是同步数字体系（SDH)信号， 所述第二非光传送网 维护信号是净荷区全部为固定值且再生段和复用段开销正常的信号。 相应地， 本发明还提供了一种光传送网信号到非光传送网信号的转换装 置， 应用于执行从光传送网信号中解映射出非光传送网信号的网元中， 该网 元所在网络包括具有嵌套关系的内嵌光传送子网和外套非光传送子网， 该转 换装置包括：
光通道数据单元信号（ODUi )解映射单元， 设置为： 从 ODUi信号中解 映射出非光传送网信号；
光通道净荷单元（OPU )层失效检测单元， 设置为： 根据 ODUi信号的 ODU和 OPU层开销， 判断 PM-STAT开销的取值是否为该内嵌光传送子网 网元对 PM-STAT开销修改后的不会触发该外套非光传送子网保护倒换的取 值， 及判断 OPU层是否失效， 并根据检测结果输出选择控制信号；
选择单元，设置为：根据所述选择控制信号，从输入的非光传送网信号、 第一非光传送网维护信号和第二非光传送网维护信号中选择一个输出； 其中， 所述第二非光传送网维护信号是不会触发非光传送网网元保护倒 换的非光传送网维护信号， 第一非光传送网维护信号是会触发非光传送网网 元保护倒换的非光传送网维护信号。
优选地，所述 OPU层失效检测单元设置为：按照以下方式输出相应的选 择控制信号：
检测到 ODUi信号中的 PM-STAT开销取值等于对 PM-STAT开销修改后 的不会触发该外套非光传送子网保护倒换的取值时， 输出用于选择第二非光 传送网维护信号的选择控制信号；
检测到 PM-STAT开销取值不等于对 PM-STAT开销修改后的不会触发 该外套非光传送子网保护倒换的取值且 OPU层失效时，输出用于选择第一非 光传送网维护信号的选择控制信号；
检测到 PM-STAT开销取值不等于对 PM-STAT开销修改后的不会触发 该外套非光传送子网保护倒换的取值且 OPU层正常时，输出用于选择非光传 送网信号的选择控制信号。
优选地，所述 OPU层失效检测单元使用的不会触发该外套非光传送子网 保护倒换的取值为 3比特的 000, 010, 011 , 100中的一种；
且， 所述非光传送网信号是有物理编码子层（PCS )编码的信号， 所述 第二非光传送网维护信号是没有数据帧且全是空闲帧的信号； 或者， 所述非 光传送网信号是同步数字体系（SDH)信号， 所述第二非光传送网维护信号是 净荷区全部为固定值且再生段和复用段开销正常的信号。
相应地， 本发明还提供了一种执行从光传送网信号解映射出非光传送网 信号处理的网元， 包括本发明的上述转换装置。
本发明要解决的又一技术问题是提供一种防止嵌套的多个子网同时倒换 的方法。
为了解决上述技术问题， 本发明提供了一种防止嵌套的多个子网同时倒 换的方法， 所应用的网络包括具备保护倒换功能且直接嵌套的一对内嵌子网 和外套子网， 其中的内嵌子网为光传送子网， 该方法包括：
该内嵌子网的所有网元均执行本发明上述基于 ODU层失效检测的开销 修改方法， 或者， 该内嵌子网中执行该内嵌光传送子网保护倒换切换的网元 执行本发明上述基于 TCM层失效检测的开销修改方法；
设置该外套子网中执行保护倒换切换的网元的保护倒换延迟触发时间小 于对应内嵌子网发生保护倒换时可能引起的最长业务瞬断时间。
优选地，该外套子网为光传送子网；或者，该外套子网为非光传送子网， 所述方法还包括： 该网络中执行从光传送网信号中解映射出非光传送网信号 的网元执行如上所述的转换方法。
优选地， 该内嵌子网中没有嵌套其他的光传送子网； 或者
该内嵌子网中还嵌入有其他的光传送子网， 且该内嵌子网中执行该内嵌 光传送子网保护倒换切换的网元执行本发明上述基于 TCM层失效检测的开 销修改方法， 所述方法还包括： 该内嵌子网中同时作为内嵌子网和外套子网 的每一光传送子网中， 执行该光传送子网保护倒换切换的网元均执行本发明 上述基于 TCM层失效检测的开销修改方法， 且执行的开销修改方法中的该 内嵌光传送子网指该光传送子网。
优选地， 该内嵌子网的所有网元均执行本发明上述基于 ODU层失效检 测的开销修改方法， 该外套子网中执行保护倒换切换的网元不支持设置保护 倒换延迟触发时间， 或将保护倒换延迟触发时间设置为 0, 或将保护倒换延 迟触发时间设置为小于等于 5ms的非零值； 或者， 该内嵌子网中执行该内嵌 光传送子网保护倒换切换的网元执行本发明上述基于 TCM层失效检测的开 销修改方法， 该外套子网中执行保护倒换切换的网元设置的保护倒换延迟触 发时间大于等于完成开销修改所需的时间且小于等于 10ms。
相应地， 本发明提供的一种包括具备保护倒换功能且直接嵌套的一对子 网的网络， 其中的内嵌子网为光传送子网， 其中： 效检测的开销修改方法的网元， 或者， 该内嵌子网中执行该内嵌光传送子网 保护倒换切换的网元釆用本发明上述执行基于 TCM层失效检测的开销修改 方法的网元； 该外套子网中执行保护倒换切换的网元设置的保护倒换延迟触 发时间小于对应内嵌子网发生保护倒换时可能引起的最长业务瞬断时间。
优选地，该外套子网为光传送子网；或者，该外套子网为非光传送子网， 该网络中执行从光传送网信号中解映射出非光传送网信号的网元釆用上述执 行从光传送网信号解映射出非光传送网信号处理的网元。
优选地， 该内嵌子网中没有嵌套其他的光传送子网； 或者
该内嵌子网中还嵌入有其他的光传送子网， 且该内嵌子网中执行该内嵌 光传送子网保护倒换切换的网元釆用本发明提供的内嵌光传送子网中执行该 内嵌光传送子网保护倒换切换的网元， 该内嵌子网中同时作为内嵌子网和外 套子网的每一光传送子网中， 执行该光传送子网保护倒换切换的网元均釆用 本发明提供的内嵌光传送子网中执行该内嵌光传送子网保护倒换切换的网元 且其中的开销修改装置处理时以该光传送子网为内嵌光传送子网。
优选地， 该内嵌子网的所有网元均釆用本发明提供的内嵌光传送子网的 网元， 该外套子网中执行保护倒换切换的网元不支持设置保护倒换延迟触发 时间， 或将保护倒换延迟触发时间设置为 0, 或将保护倒换延迟触发时间设 置为小于等于 5ms的非零值； 或者， 该内嵌子网中执行该内嵌光传送子网保 护倒换切换的网元釆用本发明提供的内嵌光传送子网中执行该内嵌光传送子 网保护倒换切换的网元， 该外套子网中执行保护倒换切换的网元设置的保护 倒换延迟触发时间大于等于完成开销修改所需的时间且小于等于 10ms。
上述方案， 在多个具备保护功能的子网之间有嵌套关系时， 可实现只有 应该发生保护倒换的子网发生保护倒换， 其他不应该发生保护倒换的子网不 会发生倒换， 且保护倒换延迟触发时间 Th可以设置得很短， 如为 0或小于 10ms的非零值，在所有子网的保护倒换系统都正常工作且出现任意单点故障 时， 具备保护倒换功能的子网都不会出现保护倒换超时现象。 并且， Th可以 统一配置， 减少了配置的工作量。 附图概述
图 1为两个以串联方式连接且具备保护倒换功能的光传送子网的组网图。 图 2是图 1中的网元 3检测到故障后传递的 TCM开销的示意图。
图 3是具有嵌套关系且具备保护倒换功能的两个光传送子网的示例性的 组网图。
图 4是图 3中网元 3检测到故障后传递的 TCM开销的示意图。
图 5是具备保护倒换功能的光传送子网嵌套于具备保护倒换功能的非光 传送子网中的示例性的组网图。
图 6是执行非光传送网信号和光传送网信号的相互转换的网元的结构及 信号处理的示意图。
图 7是 ODU层失效处理方法的示意图。
图 8是 OPU层失效处理方法的示意图。
图 9是实现光传送网信号 OTUk和光传送网信号 OTUk的相互转换的网 元的结构及信号处理的示意图。
图 10是本发明实施例一的开销修改方法的流程图。
图 11是本发明实施例一的开销修改装置的结构示意图。
图 12是本发明实施例二的开销修改方法的流程图。
图 13是本发明实施例二的开销修改装置及 ODU层失效处理装置的结构 示意图。
图 14是本发明实施例三的开销修改方法的流程图。
图 15是本发明实施例三的开销修改装置及 ODU层失效处理装置的结构 示意图。
图 16 是具备嵌套关系且具备保护倒换功能的多个光传送子网的一示例 性的组网图。
图 17是本发明实施例六的转换方法的流程图。
图 18是本发明实施例六的转换装置的结构示意图。 图 19 是具备保护倒换功能的光传送子网嵌套于具备保护倒换功能的非 光传送子网中的另一示例性的组网图。
图 20是本发明应用示例一的网络结构的示意图。
图 21是图 20中网元 3检测到故障到网元 4启动保护倒换前各网元的状 态示意图。
图 22是本发明应用示例二的网络结构的示意图。
图 23是图 22中网元 3检测到故障到网元 4启动保护倒换前各网元的状 态的示意图。
图 24是图 22中网元 1检测到故障到网元 C6启动保护倒换前各网元的 状态的示意图。
本发明的较佳实施方式
下文中将结合附图对本发明的实施例进行详细说明。 需要说明的是， 在 不冲突的情况下， 本申请中的实施例及实施例中的特征可以相互任意组合。
如前所述， 光传送网网元实现光传送网信号的处理， 光传送网信号包括
ODUi(i=0,l,2,3,4,2e,3e,flex)和 OTUk ( k=l,2,3,4,2e,3e ) 两种， 其中 ODUi用 来实现对非光传送网信号的封装和管理， OTUk 负责在光传送网网元之间传 送 ODUi。 光传送网网元对 OTUk信号的处理方法有两种， 一种处理方法是 实现非光传送网信号例如以太网、 SDH ( Synchronous Digital Hierarchy, 同步 数字体系 )信号、 光纤通道信号 （Fiber Channel )和光传送网 OTUk信号的 相互转换，另一种处理方法是实现光传送网信号 OTUk和光传送网信号 OTUk 的相互转换。
才艮据光传送网标准（ ITU-T G.709和 G.798 ) , 光传送网网元具备两种业 务失效处理方法， 一种为 ODU 层失效处理方法， 一种为 OPU ( Optical Channel Payload Unit, 光通道净荷单元）层失效处理方法。 光传送网网元的 失效处理方法会影响光传送网和非光传送网网元的保护倒换， 光传送网网元 的失效处理方法能够保证失效状态在网元间稳定地传送， 从而能够保证具备 保护倒换切换功能的网元正确检测到上游发生的业务失效状态从而触发保护 倒换。
图 6示出了现有的执行非光传送网信号和光传送网 OTUk信号的相互转 换的网元的信号处理过程。 图中， 此网元实现 n个非光传送网信号 （非光传 送网信号 1 , 非光传送网信号 2, 非光传送网信号 n )到 m个光传送网信 号 OTUk ( OTUkl,OTUk2,...， OTUkm )的相互转换， 转换过程为非光传送网 信号先转换为速率接近的 ODUi信号， 然后 ODUi信号经过 ODUi交叉矩阵 的调度，经过调度后的 n个 ODUi信号根据用户需要汇聚成 m个更高速率的 OTUk信号。
根据光传送网标准，在多个低速 ODUi和 ODUk的转换模块中包括 ODU 层失效处理装置以进行 ODU层失效处理， 方法请参照图 7, 当 ODUi交叉矩 阵输出的 ODUi在汇聚到 ODUk以前， 要先判断 ODUi是否失效， 如果失效 则插入 ODUi-AIS信号替换失效的 ODUi信号， 再进行后续处理； 同样， 在 从 ODUk解汇聚出 ODUi送入 ODU交叉矩阵以前， 也要先判断该 ODUi是 否失效，如果失效则用 ODUi-AIS信号替换失效的 ODUi信号送入 ODU交叉 矩阵。如果光传送子网中的上游网元已经插入 ODUi-AIS替换失效的 ODUi, 从 ODUk解汇聚出的 ODUi信号是 ODUi-AIS,此处的 ODU层失效检测时会 认为该 ODUi是正常的 ODUi信号并透传， 不会判断 ODU层失效而再次插 入 ODUi-AIS。
在非光传送网信号和 ODUi的转换模块中包括 OPU层失效处理装置以进 行 OPU层失效处理， 方法请参照图 8, 在从 ODUi中解映射出非光传送网信 号（从分层看， ODUi信号解映射出非光传送网信号时先解映射为 OPU层信 号 OPUi再解映射出非光传送网信号）时， 要检测 OPU层是否失效， 如果失 效则用非光传送网维护信号替换非光传送网信号。 此外， 非光传送网信号和 ODUi的转换模块也包括 ODU层失效处理装置以对 ODUi信号进行 ODU层 失效处理。
对于不同的非光传送网信号， 非光传送网维护信号有不同的定义， 光传 送网标准 G.709 中有对常见的非光传送网维护信号的定义， 例如对于 SDH ( Synchronous Digital Hierarchy, 同步数字体系 )信号， 非光传送网维护信号 为 PN-11 ;对于 10GBASE-R以太网信号（ IEEE802.3定义的万兆以太网信号）， 非光传送网维护信号为 Local Fault OrderSet。 OPU层失效处理方法的原则就 是如果检测到输入的信号失效， 则要用一种有特定信号格式的信号即定义的 非光传送网维护信号代替失效的信号继续处理， 这种有特定信号格式的信号 会被接收其的设备认为是信号失效。
图 9所示为实现光传送网信号 OTUk和光传送网信号 OTUk( k取值为 1 ,
2 , 3 , 4 , 2e,3e ) 的相互转换的网元。 图中没有非光传送网信号， 只有各种 OTUk信号， 可以视为图 6所示的网元的一部分。 同理， 在图中的多个低速 ODUi和 ODUk的转换模块中包括 ODU层失效处理装置以进行 ODU层失效 处理， 处理方法同图 9中的 ODU层失效处理装置。
实施例一
本实施例提供了一种应用于内嵌光传送子网网元中的开销修改方法， 如 图 10所示， 包括：
步骤 110 , 检测到有故障发生， 且该故障会触发该内嵌光传送子网及其 中嵌入有该内嵌光传送子网且具有保护倒换功能的外套子网保护倒换； 步骤 120 , 将要传送到下游网元的信号中会触发所述外套子网保护倒换 的开销的取值修改为不会触发所述外套子网保护倒换的取值， 且不修改会触 发该内嵌光传送子网保护倒换的开销；
步骤 130 , 所述修改持续一段时间后， 取消所述修改， 该段时间小于等 于设定的修改持续时间。
相应地，如图 11所示，本实施例提供的应用于内嵌光传送子网网元中的 开销修改装置包括：
修改控制单元 10,用于在检测到有故障发生时通知开销修改单元进行修 改， 其中， 该故障会触发该内嵌光传送子网及其中嵌入有该内嵌光传送子网 且具有保护倒换功能的外套子网保护倒换； 以及在修改持续一段时间后， 通 知开销修改单元取消修改， 该段时间小于等于设定的修改持续时间。
开销修改单元 11 , 用于在修改控制单元通知修改时， 将要传送到下游网 元的信号中会触发所述外套子网保护倒换的开销的取值修改为不会触发所述 外套子网保护倒换的取值， 且不修改会触发该内嵌光传送子网保护倒换的开 销； 以及在修改控制单元通知取消修改时， 取消所述修改。
本实施例的开销修改方法可以在网元检测到有故障发生后， 暂时屏蔽掉 其输出给下游网元的会触发外套子网保护倒换的开销信息， 使外套子网中的 网元感知不到内嵌子网保护倒换期间产生的业务瞬断， 进而可以达到内嵌子 网发生保护倒换但暂时不触发外套子网保护倒换的效果。
实施例二
本实施例基于 ODU层失效检测的开销修改方法， 应用于内嵌光传送子 网的网元中， 如图 12所示， 包括：
步骤 210, 检测到 ODU层变为失效；
此处可以釆用现有标准中的检测方法。
步骤 220, 将插入以替换失效 ODUi信号的 ODUi-AIS信号中会触发对 应外套子网保护倒换的开销的取值修改为不会触发所述外套子网保护倒换的 取值， 且不修改会触发该内嵌光传送子网保护倒换的开销；
上述会触发该内嵌光传送子网保护倒换的开销， 是分配给该内嵌光传送 子网的 TCMn-STAT开销 , 1≤n≤6；
所述外套子网中嵌入有该内嵌光传送子网且具有保护倒换功能， 该内嵌 光传送子网对应的外套子网可以有一个或多个， 其中最外层的外套子网为光 传送子网或非光传送子网， 如有其他外套子网， 所述其他外套子网均为光传 送子网；
对其中的一个外套子网：
如该外套子网为光传送子网， 所述会触发该外套子网保护倒换的开销是 分配给该外套子网的 TCMn-STAT开销；
如该外套子网为非光传送子网， 所述会触发该外套子网保护倒换的开销 是 PM-STAT开销。
按标准规定， 分配给具有嵌套关系的各个光传送子网的 TCMn-STAT开 销互不相同。
上述 TCMn-STAT和 PM-STAT开销都是 G.709标准中定义的开销， 其 长度都是 3比特， 其取值（二进制）含义在 G.709中定义如下。
表 1 TCMn-STAT的定义
Figure imgf000022_0001
表 2: PM-STAT的定义
Figure imgf000022_0002
在修改开销时，如修改 TCMn-STAT开销，修改后表示为 TCMn-STATt, 则 TCMn-STATt的取值可为 3比特的 011 , 100, 001 , 010中的一种， 这些 取值不会触发外套光传送子网保护倒换； 如修改 PM-STAT开销， 修改后表 示为 PM-STATp, 则 PM-STATp的取值可为 3比特的 000, 010, 011 , 100 中的一种，从光传送网信号解映射出非光传送网信号时 PM-STATp的这些取 值不会触发插入现有标准中定义的非光传送网维护信号 （会触发非光传送网 保护倒换， 文中称为第一非光传送网维护信号） ， 进而导致下游的非光传送 网网元保护倒换。
步骤 230, 在设定的修改持续时间内， 如果检测到 ODU层恢复正常， 执 行步骤 240, 否则， 执行步骤 250;
上述修改持续时间由内嵌子网发生保护倒换时可能引起的最长业务瞬断 时间决定， 如等于该最长业务瞬断时间。
步骤 240, 取消所述修改， 结束；
按现有标准， ODU层恢复正常后会取消 ODUi-AIS信号的插入， 用正常 的 ODUi信号进行后续处理， 此时可以同时取消对 ODUi-AIS信号的修改， 在另一实施方式中， 也可以在设定的修改持续时间到时再取消对 ODUi-AIS 信号的修改。
步骤 250,设定的修改持续时间到时 ODU层还没有恢复正常，取消所述 修改。
ODU层还没有恢复正常即 ODU层还处于失效状态， 取消对 ODUi-AIS 的修改后， 经过 ODU层失效处理后输出的是插入的未经修改的 ODUi-AIS 信号。
应当说明的是， 如果存在多层嵌套， 应用上述方法的网元可能会同时属 于多个内嵌光传送子网， 此时， 上述方法中的该内嵌光传送子网指该网元所 属的多个内嵌光传送子网中最内层的内嵌光传送子网。 例如， 光传送子网 C 嵌入在光传送子网 B中， 光传送子网 B又嵌入在光传送子网 A中， 那么， 对于光传送子网 B中不属于光传送子网 C的网元，执行上述开销修改方法时 以光传送子网 B为内嵌光传送子网，修改分配给光传送子网 A的开销， 不修 改分配给光传送子网 B的开销，修改持续时间设置为光传送子网 B发生保护 倒换时可能引起的最长业务瞬断时间。 对于光传送子网 C中的网元， 同时属 于内嵌子网 C和 B,则执行上述开销修改方法以光传送子网 C为内嵌光传送 子网， 此时修改分配给光传送子网 B和 A的开销， 不修改分配给光传送子网
C的开销， 修改持续时间设置为光传送子网 C发生保护倒换时可能引起的最 长业务瞬断时间。 对于应用上述方法的内嵌光传送子网网元， 上述方法还可以增加一个处 理， 即在设定的修改持续时间内， 如检测到所述 ODU层失效无法被该内嵌 光传送子网的保护倒换系统恢复时， 立即取消所述修改。
本实施例的开销修改方法在网元检测到 ODU层失效后， 会暂时屏蔽掉 其输出给下游网元的会触发外套子网保护倒换的开销信息， 使外套子网中的 网元感知不到内嵌子网在保护倒换期间产生的业务瞬断。
为了实现上述方法， 本实施例还提供了一种基于 ODU层失效检测的开 销修改装置 21 , 应用于内嵌光传送子网的网元中， 如图 13所示， 包括修改 控制单元 211和开销修改单元 212 , 其中：
修改控制单元 211 , 用于根据输入的 ODU层失效指示信号、用于指示开 销是否可以修改的开销指示信号及设定的修改持续时间信号， 输出修改指示 信号， 其中， 该修改指示信号在 ODU层失效指示信号指示 ODU层变为无效 时， 指示修改被开销指示信号指示为可修改的会触发对应外套子网保护倒换 的开销且不修改被开销指示信号指示为不可修改的会触发该内嵌光传送子网 保护倒换的开销， 及在修改持续一段时间后， 通知开销修改单元取消修改， 该段时间小于等于设定的修改持续时间。
开销修改单元 212, 用于根据修改指示信号的指示，将输入的 ODUi-AIS 中会触发对应外套子网保护倒换的开销的取值修改为不会触发所述外套子网 保护倒换的取值且不修改会触发该内嵌光传送子网保护倒换的开销， 然后输 出； 及根据修改指示信号的指示， 取消所述修改。
上述输入修改控制单元的开销指示信号可作为网管设置的参数， 其指示 的可修改的开销包括会触发对应外套子网保护倒换的开销， 其指示的不可修 改的开销包括会触发该内嵌光传送子网保护倒换的开销， 具体请参照步骤 220的说明， 此处不再重复。 该开销指示信号可以是一个 7比特信号， 每个 比特代表 PM-STAT和 6个 TCMn-STAT ( 1<η<6 ) 中的一个， 比特值表示该 比特代表的 PM-STAT或 TCMn-STAT开销的取值是否可以修改， 如用 0表 示可以修改， 1 表示不可以修改。 修改持续时间信号也可以作为网管设置的 参数，如可以设置为内嵌子网发生保护倒换时可能引起的最长业务瞬断时间。 在一个示例中，在 ODU层失效指示信号指示 ODU层变为失效且失效持续时 间未达到修改持续时间时， 输出上述 7比特的开销指示信号作为修改指示信 号， 在其他情况下输出全 1的 7比特信号， 其中， 比特值为 0表示该比特代 表的开销要修改，为 1表示该比特代表的开销不修改。但本发明不局限于此， 也可以用软件或者其他硬件结构来实现修改控制单元的功能。
上述修改控制单元在修改持续一段时间后，通知开销修改单元取消修改， 可以是： 所述修改控制单元在设定的修改持续时间到时， 通知开销修改单元 取消修改； 或者是， 所述修改控制单元在设定的修改持续时间到时如 ODU 层还没有恢复正常， 通知开销修改单元取消修改， 及在所述设定的修改持续 时间内， 如 ODU层恢复正常， 立即通知开销修改单元取消修改。
开销修改单元对 PM-STAT或 TCMn-STAT开销修改后的取值， 请参照 步骤 220的说明。
在本实施例的一个变例中，对于内嵌子网实际执行保护倒换切换的网元， 可以在本实施例的开销修改装置中增加一个倒换检测单元， 如增加一硬件检 测电路， 用于在 ODU层失效指示信号指示 ODU层变为失效后，检测故障是 否可以被该内嵌光传送子网的保护倒换系统恢复并通知修改控制单元， 相应 地， 该修改控制单元还用于在 ODU层失效的持续时间未达到设定的修改持 续时间， 就获知故障无法被该内嵌光传送子网的保护倒换系统恢复时， 输出 指示取消所述修改的修改指示信号。 经过以上改进后， 在内嵌子网保护倒换 失败的情况下， 可以将修改持续时间带来的外套子网的保护倒换延时降低到 最低程度。
本实施例还提供了一种内嵌光传送子网的网元， 包括本实施例提供的基 于 ODU层失效检测的开销修改装置 21和 ODU层失效处理装置 22,如图 13 所示， ODU层失效处理装置 22包括：
ODU层失效检测单元 221 , 用于根据 ODUi信号中的 ODU开销， 检测 ODU层是否失效， 并输出 ODU层失效指示信号。
选择单元 222,本实施例是一个 2选 1选择器，用于在 ODU层失效指示 信号指示 ODU层正常时， 输出 ODUi信号， 当 ODU层失效指示信号指示 ODU层失效时，输出来自开销修改装置的未经修改或修改后的 ODUi-AIS信 号。 上述 ODU层失效处理装置的结构和在网元中的位置均与现有 ODU层失 效处理装置相同， 只是原来的输入信号 ODUi-AIS变为开销修改装置输出的 未经修改或修改后的 ODUi-AIS信号。
如果该网元同时属于多个内嵌光传送子网， 修改控制单元的开销指示信 号和修改持续时间按照该网元所属的最内层内嵌光传送子网进行设置。例如， 光传送子网 C嵌套于光传送子网 B中，光传送子网 B又嵌套于光传送子网 A 中， 那么， 对于光传送子网 B中不属于光传送子网 C的网元， 按照内嵌子网 为光传送子网 B进行参数设置。对于光传送子网 C中的网元， 同时属于内嵌 子网 C和 B, 则按照内嵌子网为最内层的光传送子网 C来进行参数设置。 在 ODU层没有失效时输出正常的 ODUi信号，如果检测到 ODU层变为失效 则插入修改后的 ODUi-AIS信号， 且修改后 ODUi-AIS信号的持续时间不会 超过设定的修改持续时间， 从而暂时蔽掉其输出给下游网元的会触发外套子 网保护倒换的开销信息。
实施例三
实施例二基于 ODU层失效的开销修改方法需要用于内嵌光传送网的所 有网元， 因为如果只在一个网元如执行该内嵌光传送子网保护倒换切换的网 元上应用该方法，当上游检测出故障的网元插入 ODUi-AIS替换失效的 ODUi 后， 该网元会认为上游网元传送来的 ODUi信号是正常信号， 从而不会进行 开销修改， 这样实现起来较为麻烦。
本实施例提出一种基于 TCM层失效检测的开销修改方法， 应用于内嵌 光传送子网中执行保护倒换切换的网元， 如图 14所示， 包括：
步骤 310,根据 ODU层失效处理前的 ODUi信号检测到该内嵌光传送子 网中执行保护倒换处理时检测的 TCM层变为失效；
此处的 ODU层失效处理可以釆用现有标准中的方法，在 ODU层失效时 插入用于替换失效 ODUi信号的 ODUi-AIS信号。
每一种 TCMn-STAT开销构成一个 TCM层， l≤n≤6, TCM层变为失效 是指该 TCM层的取值会触发该内嵌光传送子网保护倒换， 例如， 检测到符 合以下条件中的一种或多种就认为该 TCM层失效：
该 TCM层的服务层变为失效；
该 TCM层变为 AIS、 连接锁定指示（LCK ) 、 连接断开指示（OCI )或 串型连接丟失（LTC )状态。
步骤 320 , 将 ODU 层失效处理后输出的正常 ODUi 信号或插入的
ODUi-AIS 信号中会触发所述外套子网保护倒换的开销的取值修改为不会触 发所述外套子网保护倒换的取值， 且不修改会触发该内嵌光传送子网保护倒 换的开销；
上述外套子网、 会触发所述外套子网保护倒换的开销、 会触发该内嵌光 传送子网保护倒换的开销， 及不会触发所述外套子网保护倒换的取值与实施 例二相同， 见步骤 220下的说明。
步骤 330,在所述设定的修改持续时间内，如果检测到该 TCM层恢复正 常， 执行步骤 340, 否则， 执行步骤 350;
上述修改持续时间由内嵌子网发生保护倒换时可能引起的最长业务瞬断 时间决定， 如等于该最长业务瞬断时间。
步骤 340, 取消所述修改， 结束。
步骤 350, 设定的修改持续时间到时， 取消所述修改， 结束。
与实施例二类似的， 如果存在多层嵌套， 应用上述方法的网元可能会同 时属于多个内嵌光传送子网， 此时， 上述方法中的该内嵌光传送子网指该网 元所属的多个内嵌光传送子网中最内层的内嵌光传送子网。
上述方法还可以增加一个处理， 即在设定的修改持续时间内， 如检测到 所述 TCM层失效无法被该内嵌光传送子网的保护倒换系统恢复时， 立即取 消所述修改。
本实施例的开销修改方法在网元检测到 ODU层失效后， 会暂时屏蔽掉 其输出给下游网元的会触发外套子网保护倒换的开销信息， 使外套子网中的 网元感知不到内嵌网元在保护倒换期间产生的业务瞬断。
为了实现上述方法， 本实施例提供了一种开销修改装置 31 , 应用于内嵌 光传送子网中执行该内嵌光传送子网保护倒换切换的网元中， 如图 15所示， 该开销修改装置 31包括：
TCM层失效检测单元 311 , 用于检测 ODU层失效处理前的 ODUi信号 中指定的 TCM层，并输出指示该 TCM层是否有效的 TCM层失效指示信号， 其中，该指定的 TCM层是被输入的 TCM层指示信号指示为该内嵌光传送子 网中执行保护倒换处理时检测的 TCM层。
修改控制单元 312, 用于根据输入的 TCM层失效指示信号、用于指示开 销是否可以修改的开销指示信号及设定的修改持续时间信号， 输出修改指示 信号， 其中， 该修改指示信号在 TCM层失效指示信号指示 TCM层变为无效 时， 指示修改被开销指示信号指示为可修改的会触发对应外套子网保护倒换 的开销且不修改被开销指示信号指示为不可修改的会触发该内嵌光传送子网 保护倒换的开销， 及在修改持续一段时间后， 通知开销修改单元取消修改， 该段时间小于等于设定的修改持续时间。
开销修改单元 313 , 用于根据修改指示信号的指示，将 ODU层失效处理 后输出的正常的 ODUi信号或插入的 ODUi-AIS信号中会触发对应外套子网 保护倒换的开销的取值修改为不会触发所述外套子网保护倒换的取值且不修 改会触发该内嵌光传送子网保护倒换的开销， 然后输出； 及根据修改指示信 号的指示， 取消所述修改。
上述执行保护倒换处理时检测的 TCM层是 6个 TCMn 中的一个， TCM 层指示信号可以是一个 6比特信号， 其中只有一个比特的比特值表示该比特 代表的 TCM层需要检测，即只检测一个 TCM层的开销，具体检测哪个 TCM 层开销可以由网管软件设置。 TCM层失效检测的方法见本实施例方法中步骤 310下的说明。
修改控制单元 312与实施例二的修改控制单元 211的结构、 开销指示信 号和修改指示信号的格式及控制逻辑可以相同， 不再赘述， 差别只是两者接 收的失效指示信号一个是指示 ODU层是否失效而另一个是指示 TCM层是否 失效。上述修改控制单元 312在修改持续一段时间后，通知开销修改单元 313 取消修改， 可以是： 修改控制单元 312在设定的修改持续时间到时， 通知开 销修改单元 313取消修改； 或者是， 修改控制单元 312在设定的修改持续时 间到时如 TCM层还没有恢复正常， 通知开销修改单元 313取消修改， 及在 所述设定的修改持续时间内， 如 TCM层恢复正常， 立即通知开销修改单元
313取消爹改。
开销修改单元 313要修改的开销与实施例二一样， 也是 PM-STAT开销 和 6个 TCMn-STAT开销中的部分开销，但所修改的信号除插入的 ODUi-AIS 外， 也可能是 ODU层失效处理后输出的正常的 ODUi信号。
本实施例的一个变例中，可以在本实施例的开销修改装置 31中增加一个 倒换检测单元， 如增加一硬件检测电路， 用于在 TCM层失效指示信号指示 TCM层变为失效后，检测故障是否可以被该内嵌光传送子网的保护倒换系统 恢复并通知修改控制单元， 相应地， 该修改控制单元 312还用于在 TCM层 失效的持续时间未达到设定的修改持续时间就获知故障无法被该内嵌光传送 子网的保护倒换系统恢复时， 输出指示取消所述修改的修改指示信号。
本实施例还提供了一种内嵌光传送子网中执行该内嵌光传送子网保护倒 换切换的网元， 包括本实施例提供的基于 TCM层失效检测的开销修改装置 31和 ODU层失效处理装置 32, 如图 15所示， 该 ODU层失效处理装置 32 包括 ODU层失效检测单元 321和选择单元 322, 用于在 ODU层正常时， 输 出正常的 ODUi信号， 在 ODU层失效时， 输出插入以替换失效的 ODUi信 号的 ODUi-AIS信号。 本实施例的 ODU层失效处理装置 32的结构、 在网元 中的位置和输入的信号均可与现有的 ODU层失效处理装置相同。 如果该网 元同时属于多个内嵌光传送子网， 修改控制单元的开销指示信号和修改持续 时间按照该网元所属的多个内嵌光传送子网中最内层的内嵌光传送子网进行 设置。
本实施例提供的内嵌光传送子网中执行该内嵌光传送子网保护倒换切换 的网元可以根据 TCM层失效检测结果， 在检测到 TCM层变为失效时修改 ODU层失效处理后输出的正常的 ODUi信号或插入的 ODUi-AIS信号中会触 发对应外套子网保护倒换的开销， 且对信号进行修改的持续时间不会超过设 定的修改持续时间， 从而暂时蔽掉该网元输出给下游网元的会触发外套子网 保护倒换的开销信息。
实施例四
本实施例提供一种防止嵌套的多个子网同时倒换的方法， 所应用的网络 包括具备保护倒换功能且直接嵌套的一对子网， 该对子网中的内嵌子网和外 套子网均为光传送子网， 图 3是此类网络的一个示例， 图 16示出了此类网络 的另一示例， 该网络也存在外套子网和内嵌子网可能同时发生保护倒换或保 护倒换超时的问题。
本实施例防止嵌套的多个子网同时倒换的方法包括：
该内嵌子网的所有网元均执行实施例二提供的基于 ODU层失效检测的 开销^ ί'爹改方法；
设置该外套子网中执行保护倒换切换的网元的保护倒换延迟触发时间小 于对应内嵌子网发生保护倒换时可能引起的最长业务瞬断时间。
至于外套子网中不属于该内嵌子网的网元， 可以基于现有标准。
上述内嵌子网可以不再嵌入有其他的光传送子网。 如果该内嵌子网中还 嵌入有其他具有保护倒换功能的光传送子网， 即该对子网组成的网络中还包 括内层外套子网 （即同时是内嵌子网和外套子网） ， 此时该外套子网中执行 保护倒换切换的网元包括执行内层外套子网保护倒换切换的网元。
釆用上述方法， 可以避免网络中多个嵌套的子网的保护倒换系统同时发 生倒换。 而当外套子网中不属于内嵌子网的网元发生故障时， 此故障会被外 套子网中执行保护倒换切换的网元检测到， 由于该网元的保护倒换延迟触发 时间小于该内嵌子网发生保护倒换时可能引起的最长业务瞬断时间， 因此在 该内嵌子网外和外套子网内发生故障时， 可以缩短现有技术将保护倒换延迟 触发时间设置为该最长业务瞬断时间而导致保护倒换造成的业务瞬断时间。 在一些示例中， 该外套子网中执行保护倒换切换的网元可以不支持设置保护 倒换延迟触发时间 （无延迟触发） ， 或将保护倒换延迟触发时间设置为 0, 该故障会立刻触发外套子网的保护倒换， 并且外套子网不用根据内嵌子网是 否存在保护倒换以及其保护倒换所造成的最长业务瞬断时间修改 Th的设置， 维护工作量将极大减轻。 在另一示例中， 也可以将保护倒换延迟触发时间设 置为小于等于 5ms的非零值， 这些示例都可以进一步避免该故障引起的保护 倒换超时。
相应地， 本实施例还提供了一种包括一对具备保护倒换功能且直接嵌套 的子网的网络， 该对子网中的内嵌子网和外套子网均为光传送子网， 其中： 该内嵌子网中的所有网元均釆用实施例二提供的内嵌光传送子网的网元, 其中具有基于 ODU层失效检测的开销修改装置； 及
该外套子网中执行保护倒换切换的网元设置的保护倒换延迟触发时间小 于对应内嵌子网发生保护倒换时可能引起的最长业务瞬断时间。
上述内嵌子网可以不再嵌入有其他的光传送子网。 如果上述内嵌子网还 嵌入有其他的光传送子网， 此时该外套子网中执行保护倒换切换的网元包括 执行内层外套子网保护倒换切换的网元。 在一个示例中， 该外套子网中执行 保护倒换切换的网元可以不支持设置保护倒换延迟触发时间， 或将保护倒换 延迟触发时间设置为 0, 或将保护倒换延迟触发时间设置为小于等于 5ms的 非零值。
在本实施例的一个示例中， 包括两个有直接嵌套关系且都具备保护功能 的光传送子网 A和光传送子网 B, 光传送子网 A中嵌入有光传送子网 B, 即 子网 B的所有网元都在子网 A的工作或保护路径上。
假定光传送子网 A使用 TCMa(l≤a≤6)作为子网保护倒换判断依据，光传 送子网 B使用 TCMb(l≤b≤6)作为子网保护倒换判断依据， 根据光传送网的 TCM实现原理， a—定不等于 b, 为了实现本发明所期望的效果， 在内嵌子 网 B中的所有网元应用实施例二的基于 ODU层失效检测的开销修改方法， 并且设置 TCMa-STAT开销为可修改的开销， TCMb-STAT开销为不可修改 的开销， 如配置开销修改指示信号中代表 TCMa-STAT开销的比特为 0, 代 表 TCMb-STAT开销的比特为 1 ,其余比特可任意设置。 TCMa-STAT开销的 修改持续时间可设置为内嵌子网 B发生保护倒换时可能造成的最长业务瞬断 时间。 外套子网 A中不属于子网 B的所有网元可以基于现有光传送网标准， 同时子网 A中执行保护倒换切换功能的网元设置 Th为 0。
完成上述设置后， 子网 B内部的某个网元检测到 ODU层失效， 按照实 施例二的基于 ODU 层失效检测的开销修改方法处理后， ODUi-AIS 的 TCMb-STAT开销取值为 TCMb-AIS, TCMa-STAT开销取值为修改后的取值 STATt, 因此子网 B能正常检测到业务失效从而触发保护倒换， 而子网 A检 测 TCMa-STAT开销取值为 STATt时会认为业务正常，所以不会发生保护倒 换， 这样即可防止子网 A和子网 B的保护倒换系统同时倒换。 如果子网 B 因为发生意外没有保护倒换成功， 从而导致业务一直中断， 由于对
TCMa-STAT 开销的修改只会持续一段时间， 这样在修改持续时间结束后， TCMa-STAT开销的取值将为 TCMa-AIS, 此时子网 A将发生保护倒换， 这 样显然会延长子网 A保护倒换造成的业务瞬断时间，但子网 B发生保护倒换 意外的几率非常低。
在一具有多层嵌套的示例中，三个都具备保护倒换功能的光传送子网 A, B, C之间有嵌套关系， 其中光传送子网 A中嵌入有光传送子网 B, 即子网 B的所有网元都在子网 A的工作或保护路径上，光传送子网 B中嵌入有光传 送子网 C, 即子网 C的所有网元都在子网 B的工作或保护路径上。 假定光传 送子网 A使用 TCMa作为子网保护倒换判断依据，光传送子网 B使用 TCMb 作为子网保护倒换判断依据，光传送子网 C使用 TCMc作为子网保护倒换判 断依据（a≠b≠c,l≤a≤6, l<b<6, l<c<6 ) , 在内嵌子网 Β和 C中的所有网元 应用实施例二的基于 ODU层失效检测的开销修改方法， 并且在子网 C中的 所有网元， 设置 TCMa-STAT 开销和 TCMb-STAT 开销为可修改的开销， TCMc-STAT开销为不可修改的开销， 修改开销的持续时间由内嵌子网 C发 生保护倒换时可能造成的最长业务瞬断时间决定。 同时， 在子网 B中不属于 子网 C的所有网元， 设置 TCMa-STAT开销为可修改的开销， TCMb-STAT 开销为不可修改的开销， 修改开销的持续时间由内嵌子网 B发生保护倒换时 可能导致的最长业务瞬断时间决定。外套子网 A中不属于子网 B的所有网元 可以基于现有光传送网标准。 另外，在执行子网 A和子网 B保护倒换切换的 网元均设置 Th为 0。
完成上述设置后，如子网 C内部的某个网元因为业务失效触发子网 C保 护倒换时， 不会导致子网 A和 B发生保护倒换， 子网 B内部不属于子网 C 的某个网元因为业务中断触发子网 B保护倒换时，不会导致子网 A发生保护 倒换。
类似的， 经过进一步引申， 本实施例可在最多 6个具备保护倒换功能的 光传送子网逐层嵌套的情况下实现保护倒换不互相影响。
实施例五
因为实施例二的开销^ ί'爹改方法和实施例三的开销 ^ί'爹改方法均可以暂时蔽 掉该网元输出给下游网元的会触发外套子网保护倒换的开销信息， 因而本实 施例基于实施例三的开销修改方法， 提出一种防止嵌套的多个子网同时倒换 的方法， 所应用的网络与实施例四相同， 可参照图 3和图 16, 包括具备保护 倒换功能且直接嵌套的一对子网， 该对子网中的内嵌子网和外套子网均为光 传送子网。
本实施例防止嵌套的多个子网同时倒换的方法包括：
该内嵌子网中执行该内嵌光传送子网保护倒换切换的网元执行实施例三 提供的基于 TCM层失效检测的开销修改方法；
设置该外套子网中执行保护倒换切换的网元的保护倒换延迟触发时间小 于对应内嵌子网发生保护倒换时可能引起的最长业务瞬断时间。
上述内嵌子网可以不再嵌入有其他的光传送子网。 如果上述内嵌子网还 嵌入有其他的光传送子网， 此时该外套子网中执行保护倒换切换的网元还包 括执行内层外套子网保护倒换切换的网元， 并且， 该内嵌子网中 （可以包括 该内嵌子网） 同时作为内嵌子网和外套子网的具有保护倒换功能的每一光传 送子网中， 执行该光传送子网保护倒换切换的网元均执行实施例三提供的基 于 TCM层失效检测的开销修改方法且该开销修改方法中的该内嵌光传送子 网指该光传送子网。
本实施例与实施例四相比， 只需在很少的网元上执行， 而实施例四需要 在更多的网元上执行， 花费的代价不一样。 但本实施例需要在检测到指定 TCM层失效后才能修改分配给外套子网的 TCMn-STAT开销，此时外套子网 中的网元可能已经检测到了短暂的 TCM-AIS状态从而触发保护倒换， 所以 此时外套子网中执行保护倒换切换的网元可设置一个短的保护倒换延迟触发 时间 Th, Th大于等于完成开销修改所需的时间且小于等于 10ms (已足够 完成修改） ， 使内嵌子网的网元完成所述修改之前不会进行保护倒换， 完成 修改所需的时间可以通过估算或测试得到， 具体的取值可以根据实际网络的 情况来设置， 如设置为 5ms。
相应地， 本实施例还提供了一种包括一对具备保护倒换功能且直接嵌套 的子网的网络， 该对子网中的内嵌子网和外套子网均为光传送子网， 其中： 该内嵌子网中执行该内嵌子网保护倒换切换的网元均釆用实施例三提供 的内嵌光传送子网的网元，其中具有基于 TCM层失效检测的开销修改装置； 及
该外套子网中执行保护倒换切换的网元设置的保护倒换延迟触发时间小 于对应内嵌子网发生保护倒换时可能引起的最长业务瞬断时间。
上述内嵌子网可以不再嵌入有其他的光传送子网。 如果上述内嵌子网还 嵌入有其他的光传送子网， 此时该外套子网中执行保护倒换切换的网元还包 括执行内层外套子网保护倒换切换的网元， 并且， 该内嵌子网中同时作为内 嵌子网和外套子网的每一光传送子网中， 执行该光传送子网保护倒换切换的 网元均釆用实施例三提供的内嵌光传送子网的网元， 其中的基于 TCM层失 效检测的开销修改装置处理时以该光传送子网为内嵌光传送子网。
本实施例在故障发生时， 与实施例四在故障发生时的处理相类似， 只是 本实施例是在该外套子网中执行该外套子网保护倒换切换的网元进行 TCM 层失效检测， 检测到失效后的开销修改和取消修改的处理都是类似的， 可以 参照实施例四的示例。 本实施例也可以避免网络中多个嵌套的子网的保护倒 换系统同时发生倒换， 同时缩短现有技术将保护倒换延迟触发时间设置为该 最长业务瞬断时间而导致保护倒换造成的业务瞬断时间。 在一示例中， 设置 的保护倒换延迟触发时间大于等于完成开销修改所需的时间且小于等于 10ms, 可以避免故障引起的保护倒换超时。
实施例六
如前所述， 一对具有嵌套关系且具备保护倒换功能的子网中， 如果外套 子网是非传送子网， 执行从光传送网信号解映射出非光传送网信号处理的网 元需要进行 OPU层检测， 如果检测到 OPU层失效， 会插入第一非光传送网 维护信号 （即现有标准中定义的光传送网维护信号）来替换光传送网信号传 送到下游网元。内嵌子网釆用于本发明实施例二和三提供的开销修改方法后， 在检测到故障会触发对应外套子网发生保护倒换时， 会修改 PM-STAT开销 的取值为 PM-STATp, 为了避免外套子网发生保护倒换， 此时不能立即插入 第一非光传送网维护信号， 因而本实施例定义了一种新的不会触发非光传送 网网元保护倒换的光传送网维护信号， 称为第二非光传送网维护信号， 在检 测到 PM-STAT开销的取值为修改后的 PM-STATp后， 产生该第二非光传送 网维护信号来替换解映射出的非光传送网信号传送到下游网元。 非光传送网 网元收到该第二非光传送网维护信号后， 会将其识别为正常的非光传送网信 号， 不会进行保护倒换。
本实施例提供了一种光传送网信号到非光传送网信号的转换方法， 应用 于执行从光传送网信号解映射出非光传送网信号处理的网元中， 该网元所在 网络包括具有直接嵌套关系的内嵌光传送子网和外套非光传送子网， 该转换 方法如图 17所示， 包括：
步骤 610,检测 ODUi信号中 PM-STAT开销的取值是否为该内嵌光传送 子网网元对 PM-STAT开销修改后的不会触发该外套非光传送子网保护倒换 的取值， 如果是， 执行步骤 620, 否则， 执行步骤 630;
所述 PM-STAT开销修改后的不会触发对应外套子网保护倒换的取值， 如可以为 3比特的 000, 010, 011 , 100中的一种。
步骤 620, 输出插入的第二非光传送网维护信号以替换从光传送网信号 解映射出的非光传送网信号；
上述第二非光传送网维护信号为新定义的不会触发非光传送网网元保护 倒换的非光传送网维护信号，也即检测到 PM-STAT开销的取值为 PM-STATp 后插入的， 非光传送网网元会将其识别为一个正常信号， 不会触发非光传送 网网元保护倒换的信号。
例 ^口， 对于以太网或 Fibre Channel 一类的有 PCS ( hysical coding sublayer,物理编码子层）层编码的信号，可用没有数据帧且全是空闲（ IDLE ) 帧的信号作为第二非光传送网维护信号；对于 SDH信号，可用净荷区全部为 固定值且再生段和复用段开销正常的信号作为第二非光传送网维护信号。 对 于第二非光传送网维护信号具体格式的定义不限于此， 只要其能导致非光传 送网不会触发保护倒换即可， 本领域技术人员可根据此条件修改对第二非光 传送网维护信号具体格式的定义。
步骤 630, 根据 OPU层是否失效， 输出从光传送网信号解映射出的非光 传送网信号或插入的第一非光传送网维护信号。
PM-STAT 开销的取值非 PM-STATp 时的处理与现有标准一致， 如果 OPU层失效，会插入第一非光传送网维护信号以替换从光传送网信号解映射 出的非光传送网信号，作为网元的输出信号， 否则对 OPU做正常处理， 用从 光传送网信号解映射出的非光传送网信号作为网元的输出信号。
在转换过程中上述的检测和处理会不断反复进行。
本实施例的转换方法与实施例二或实施例三的开销修改方法结合， 在内 嵌子网的网元检测到故障会触发对应外套子网发生保护倒换且对应外套子网 包括非光传送子网时， 会修改 PM-STAT的取值， 而执行从光传送网信号解 映射出非光传送网信号处理的网元（可以在内嵌子网上， 也可以只在外套子 网上）检测到 PM-STAT为修改后的取值后， 会插入第二非光传送网维护信 号以避免外套非光传送子网保护倒换， 因为 PM-STAT的修改只持续一段时 间， 因而可以达到内嵌子网网元发生保护倒换但暂时不触发外套子网网元保 护倒换的效果。
本实施例提供的光传送网信号到非光传送网信号的转换装置， 应用于执 行从光传送网信号解映射出非光传送网信号处理的网元中， 该网元所在网络 包括具有直接嵌套关系的内嵌光传送子网和外套非光传送子网， 该转换装置 如图 18所示， 包括：
ODUi解映射单元 61 , 用于从 ODUi中解映射出非光传送网信号。 可以 釆用现有的 ODUi解映射单元。
OPU层失效检测单元 62,用于根据 ODUi信号的 ODU和 OPU层开销， 判断 PM-STAT开销的取值是否等于 STATp, 及判断 OPU层是否失效， 根 据检测结果输出选择控制信号。 STATp的含义同上文， 对 OPU层失效的判 断可釆用现有标准中的方法。
选择单元 63 , 如使用 3选 1选择器， 用于根据选择控制信号， 从输入的 非光传送网信号、 第一非光传送网维护信号和第二非光传送网维护信号中选 择一个输出。
其中， OPU层失效检测单元按照以下方式输出相应的选择控制信号： 检测到 ODUi信号中的 PM-STAT开销取值等于 STATp时，输出用于选 择第二非光传送网维护信号的选择控制信号； 检测到 PM-STAT开销取值不等于 STATp且 OPU层失效时， 输出用于 选择第一非光传送网维护信号的选择控制信号； 检测到 PM-STAT开销取值不等于 STATp且 OPU层正常时， 输出用于 选择非光传送网信号的选择控制信号。 本实施例还提供了一种执行从光传送网信号解映射出非光传送网信号处 理的网元， 其中包括本实施例的上述转换装置
实施例七
本实施例应用于的网络包括具备保护倒换功能且具有直接嵌套关系的一 对子网， 其中的内嵌子网是光传送网， 而外套子网是非光传送网。 图 5是此 类网络的一个示例， 图 19示出了此类网络的另一示例，其中的子网 1和子网 2 均具备保护倒换功能， 该网络也存在外套子网和内嵌子网可能同时发生保 护倒换或保护倒换超时的问题。
本实施例防止嵌套的多个子网同时倒换的方法在实施例四或实施例五提 供的防止嵌套的多个子网同时倒换的方法的基础上， 将其中的外套子网由光 传送子网改为非光传送子网， 并增加以下特征：
执行从光传送网信号中解映射出非光传送网信号处理的网元执行实施例 六提供的光传送网信号到非光传送网信号的转换方法。
例五。
相应地， 本实施例的包括一对具备保护倒换功能且直接嵌套的光传送子 网的网络， 在实施例四或实施例五提供的网络的基础上， 将其中的外套子网 由光传送子网改为非光传送子网， 并增加以下特征：
执行从光传送网信号中解映射出非光传送网信号的网元釆用实施例六提 供的执行从光传送网信号中解映射出非光传送网信号处理的网元。
实施例五。 相对于实施例四和实施例五应用的网络， 本实施例的不同在于外套子网 为非光传送网， 因而需要在执行从光传送网信号中解映射出非光传送网信号 的网元上增加实施例六提供的光传送网信号到非光传送网信号的转换处理， 从而在开销的修改持续时间内， 不向下游的非光传送网网元传送第一非光传 送网维护信号， 避免光传送网和非光传送网同时倒换， 同时在内嵌子网外外 套子网内发生故障时， 可避免非光传送网保护倒换延时超时。
在本实施例的一个示例中， 包括两个有直接嵌套关系且都具备保护功能 的子网， 内嵌子网 B为光传送子网，使用 TCMb(l≤b≤6)作为子网保护倒换判 断依据， 外套子网 A为非光传送子网， 其保护倒换条件和非光传送子网处理 的非光传送信号类型相关， 本发明并不关心非光传送子网实际的保护倒换条 件。 为了实现本发明所期望的效果， 内嵌子网 B中的所有网元应用本实施例 二的开销修改方法， 设置 PM-STAT开销为可修改的开销， TCMb-STAT开 销为不可修改的开销， 如设置开销修改指示信号中代表 PM-STAT开销的比 特为 0, 代表 TCMb-STAT开销的比特为 1 , 其余比特可任意设置。 同时设置 PM-STAT开销的修改持续时间为内嵌子网 B发生保护倒换时可能造成的最 长业务瞬断时间。 外套子网 A中由于没有光传送网网元， 所以其没有 ODU 层处理。 同时， 网络中执行从光传送网信号中解映射出非光传送网信号处理 的网元应用实施例六的转换方法， 子网 A 中执行保护倒换切换的网元设置 Th为 0。
完成以上设置后， 子网 B内部的某个网元发生失效后， 该网元按照实施 例二的开销修改方法处理后， TCMb-STAT的取值为 TCMb-AIS, PM-STAT 的取值为 STATp, TCMb-STAT的取值为 TCMb-AIS可保证子网 B能正常保 护倒换， PM-STAT的取值为 STATp将触发网络中执行从光传送网信号中解 映射出非光传送网信号处理的网元输出第二非光传送网维护信号， 而子网 A 检测到第二非光传送网维护信号时认为业务正常， 所以不会发生保护倒换， 这样即可实现防止子网 A和子网 B同时保护倒换。 如果子网 B因为发生意 外没有保护倒换成功， 从而导致业务一直中断， 由于对 PM-STAT的修改只 会持续一段时间， 这样在修改持续时间结束后 PM-STAT的取值为 PM-AIS , 此时子网 A将收到第一非光传送网维护信号并认为业务失效从而发生保护倒 换， 这样虽然会延长子网 A保护倒换造成的业务瞬断时间，但子网 B发生保 护倒换意外的几率非常低。 另外， 当子网 A中不属于子网 B的网元发生故障 时，此故障会导致子网 A检测到第一非光传送网维护信号， 又由于子网 A中 执行保护倒换切换的网元已设置 Th为 0, 所以会立刻触发子网 A的保护倒 换。
类似的， 环境 2还可以进一步引伸， 子网 A为具备保护倒换功能的非光 传送子网， 子网 B、 C为光传送子网， 子网 B内嵌在子网 A中， 子网 C内嵌 在子网 B中， 子网 B中只有子网 C具备保护倒换功能， 子网 B中不属于子 网 C的部分不具备保护倒换功能， 也即子网 C和子网 A是本发明定义的直 接嵌套且具备保护倒换功能的一对子网。子网 C使用 TCMc(l≤c≤6)作为子网 保护倒换判断依据， 此时需要在子网 C中的所有网元应用实施例二的开销修 改方法， 网络中执行从光传送网信号中解映射出非光传送网信号处理的网元 应用实施例六的转换方法， 对于子网 C中的所有网元设置 PM-STAT开销被 修改一段时间， TCMc-STAT开销被设置为不修改， 另外子网 A中执行保护 倒换切换的网元可设置 Th为 0, 当以上要求都具备后， 子网 C发生保护倒 换时不会导致子网 A同时发生保护倒换。 同时子网 C外和子网 A内发生故 障时， 子网 A不会发生保护倒换延迟超时。
上述各实施例的开销修改方法和转换方法不会影响网络中没有应用上述 实施例的网元的正常工作。
下面结合附图对本发明的应用示例作进一步的详细描述， 下面仅按照在 内嵌光传送子网中的所有网元上釆用实施例二提供的开销修改装置来说明， 在内嵌光传送子网中执行保护倒换切换的网元上釆用实施例三提供的开销修 改装置是相似的。
应用示例一
图 20为此应用示例对应的网络结构。在此应用示例中，所有子网都是光 传送子网， 传送的业务都是 OTU2业务， 网元 1至 6为子网 B的网元， 网元 1至 10为子网 A的网元， 子网 B嵌入于子网 A中， 子网 A使用 TCM2作为 保护倒换判断依据，子网 B使用 TCM1作为保护倒换判断依据，子网 B中的 网元 1至 6应用实施例二的开销修改装置， 并且通过网管设置开销指示信号 中代表 TCM1的比特为 1表示不可修改，代表 TCM2的比特为 0表示可修改， 其余比特可以任意设置， 设置修改持续时间为 50ms, 其中 50ms为子网 B发 生保护倒换可能引起的最长业务瞬断时间， 以上设置可以在设置子网 B的保 护倒换功能时完成。 子网 A中网元 4和 10是执行保护倒换切换的网元， 对 以上两个网元设置保护倒换延迟触发时间为 0。
当网元 2到网元 3的光纤中断后， 网元 3中的开销修改装置将使得网元 3输出最多持续 50ms的修改过开销的 ODU2-AIS,其中 TCM1-STAT开销的 取值为 TCM1-AIS , TCM2-STAT 的取值为 STATt , 以上修改过开销的 ODU2-AIS传到网元 4后， 网元 4根据 TCM1-AIS可以正常倒换， 由于网元 4是 TCM1的终点， 所以网元 4输出的 ODU2-AIS中的 TCM1-STAT开销取 值为 TCM1-LTC, 其中 LTC的取值为 000, OTN标准规定位于 TCM终点的 网元需要将 TCM-STAT值修改为 TCM-LTC, 表示此 TCM为空闲， 可以被 其他网元作为 TCM的起点。同时由于网元 4始终不是 TCM2的起点或终点， 所以透传 TCM2开销， 所以从光纤中断后到网元 4发生保护倒换前网元 10 收到的 ODU2-AIS中的 TCM2-STAT开销的取值一直为 STATt,此时网元 10 认为业务正常从而不会发生保护倒换。 假设网元 4检测到网元 2和 3之间有 故障后在 t时间内切换为使用网元 5和网元 6提供的业务（t<50ms ) , 则光 纤中断 t时间后网元 4将输出正常的 OTU2信号，此时网元 10也收到正常的 OTU2信号， 这样网元 10仍旧不会发生保护倒换， 从而保证以上过程中只有 网元 4发生保护倒换。图 21为网元 3检测到故障到网元 4发生保护倒换前网 元 3、 4和 10的 TCM开销状态。
应用示例二
图 22为此应用示例对应的网络结构。在此应用示例中，非光传送网网元 C1至 C6组成一个具备保护倒换功能的非光传送子网， 光传送网网元 1至 8 组成一个光传送子网， 其中由网元 1至 6组成的光传送子网具备保护倒换功 能， 光传送子网和非光传送子网之间的接口信号为以太网信号 10GBAE-R, 光传送网网元将 10GBASE-R映射到 OTU2e, 并将 OTU2e作为光传送网内 部的信号格式在光传送网的网元之间传送。 为了实现本发明的目的， 光传送 子网中的网元 1至 6应用实施例二的开销修改装置， 并且设置开销修改指示 信号中代表 TCM1的比特为 1表示不可修改， 代表 PM的比特为 0表示可修 改， 其余比特可以任意设置， 设置修改持续时间为 50ms, 其中 50ms为网元 1-6 组成的子网发生保护倒换可能引起的最长业务瞬断时间， 以上设置可以 在设置网元 1至 6的保护功能时完成设置。 同时， 执行光传送网信号和非光 传送网信号互相转换的网元 1和 4应用实施例六的转换装置， 另外网元 4和 C6是执行保护倒换切换的网元， 设置保护倒换延迟触发时间为 0。
当网元 2到网元 3的光纤中断后，如图 23所示， 网元 3中的开销^ ί'爹改装 置将使得网元 3 输出最多持续 50ms 的修改过开销的 ODU2e-AIS , 其中 TCM1 -STAT开销的取值为 TCM1-AIS, PM-STAT开销的取值为 STATp, 网 元 4接收到上述 ODU2e-AIS后， 根据 TCM1-AIS可以正常倒换， 在网元 3 检测到故障到网元 4 发生倒换以前， 网元 4 中的转换装置将始终检测到 ODU2e-AIS的 PM-STAT开销的取值为 STATp,此时将一直输出第二以太网 维护信号， 对于 10GBASE-R以太网， 该第二以太网维护信号为没有数据帧 且全是空闲帧的 10GBASE-R格式的信号， C4和 C6也将一直收到第二以太 网维护信号， 由于位于 C6上用于实现保护倒换功能的业务失效检测电路认 为此信号为正常信号， 所以 C6不会发生保护倒换， 4艮设网元 4的保护倒换 在 t时间内完成（t<50ms ) , 则网元 2到网元 3的光纤中断 t时间后网元 4 将输出正常的 10GBASR-R 信号， 此时网元 C4 和 C6 也收到正常的 10GBASE-R信号， 这样网元 C6仍旧不会发生倒换， 从而保证以上过程中只 有网元 4发生保护倒换。图 23为网元 3检测到故障到网元 4发生保护倒换前 网元 3 , 4, C4 , C6的状态。
在上述实现环境中， 如果按照现有技术实现， 为了避免光传送子网和非 光传送子网同时保护倒换，需要设置网元 C6的保护倒换延迟触发时间 Th大 于光传送子网保护倒换造成业务瞬断的时间， 才能防止由网元 1-6组成的子 网发生保护倒换时网元 C6不发生保护倒换， 光传送子网保护倒换造成业务 瞬断的时间一般为 50ms, 为了留有余量， 网元 C3和 C6的 Th—般设置为 lOOmSo 如果网元 C1和网元 1之间的光纤中断， 如图 24所示， 此时网元 1 检测到 10GBASE-R失效后将用第一以太网维护信号替换失效的信号继续处 理，根据 G.709标准，对于 10GBASE-R以太网维护信号为 Local Fault OrderSet, 网元 1将输出正常的 OTU2e信号只是 OPU2e中的净荷为 Local Fault OrderSet, 同时网元 4检测不到 TCM1层失效所以不会触发保护倒换， 这样网元 4将输 出 Local Fault OrderSet, 网元 C4和 C6都将收到 Local Fault OrderSet, 网元 C6认为 Local Fault OrderSet代表以太网业务失效， 但由于设置了 Th, 所以 检测到 Local Fault OrderSet持续 Th时间后才会触发保护倒换， 这样网元 C6 的业务需要 100ms加业务切换时间才能恢复正常。 如果按照本发明上述实施 例七实现， 由于网元 1 至 6 没有检测到 ODU 层失效， 所以不会插入 ODU2e-AIS或修改过开销的 ODU2e-AIS, 也不会触发保护倒换， 这样釆用 上述实施例的开销修改装置后会和符合光传送网标准的相应装置得到同样的 处理结果， 网元 C4和 C6会在网元 C3和网元 1之间的光纤中断后立刻检测 到 Local Fault OrderSet, 由于 C3和 C6的 Th已经设置为 0, 所以网元 C6检 测到 Local Fault OrderSet之后会立刻发生保护倒换， 这样业务中断时间为上 述切换业务时间。 使用本发明可实现只有应该发生保护倒换的子网发生保护 倒换， 其他不应该发生保护倒换的子网不会发生倒换。 在所有子网的保护倒 换系统都正常工作且出现任意单点故障时， 具备保护倒换功能的子网的保护 倒换延时会缩短。
本领域普通技术人员可以理解上述方法中的全部或部分步骤可通过程序 来指令相关硬件完成， 所述程序可以存储于计算机可读存储介质中， 如只读 存储器、 磁盘或光盘等。 可选地， 上述实施例的全部或部分步骤也可以使用 一个或多个集成电路来实现， 相应地， 上述实施例中的各模块 /单元可以釆用 硬件的形式实现， 也可以釆用软件功能模块的形式实现。 本发明不限制于任 何特定形式的硬件和软件的结合。
以上所述仅为本发明的优选实施例而已， 并不用于限制本发明， 对于本 领域的技术人员来说， 本发明可以有各种更改和变化。 凡在本发明的精神和 原则之内， 所作的任何修改、 等同替换、 改进等， 均应包含在本发明的保护 范围之内。
工业实用性
上述方案， 在多个具备保护功能的子网之间有嵌套关系时， 可实现只有 应该发生保护倒换的子网发生保护倒换， 其他不应该发生保护倒换的子网不 会发生倒换， 且保护倒换延迟触发时间 Th可以设置得很短， 如为 0或小于 10ms的非零值，在所有子网的保护倒换系统都正常工作且出现任意单点故障 时， 具备保护倒换功能的子网都不会出现保护倒换超时现象。 并且， Th可以 统一配置， 减少了配置的工作量。

Claims

权 利 要 求 书
1、 一种开销修改方法， 应用于内嵌光传送子网的网元中， 该方法包括： 检测到有故障发生， 且该故障会触发该内嵌光传送子网及其中嵌入有该 内嵌光传送子网且具有保护倒换功能的外套子网保护倒换；
将要传送到下游网元的信号中会触发所述外套子网保护倒换的开销的取 值修改为不会触发所述外套子网保护倒换的取值， 且不修改会触发该内嵌光 传送子网保护倒换的开销；
所述修改持续一段时间后， 取消所述修改， 该段时间小于等于设定的修 改持续时间。
2、 如权利要求 1所述的开销修改方法， 其中，
所述开销修改方法应用于该内嵌光传送子网中的所有网元中；
所述检测到有故障发生，指检测到光通道数据单元（ ODU )层变为失效； 所述将要传送到下游网元的信号， 指插入以替换失效光通道数据单元信 号 （ODUi信号） 的 ODUi告警指示信号 （ODUi-AIS信号） 。
3、 如权利要求 1所述的开销修改方法， 其中，
所述开销修改方法应用于内嵌光传送子网中执行该内嵌光传送子网保护 倒换切换的网元中；
所述检测到有故障发生， 指根据 ODU层失效处理前的 ODUi信号检测 到该内嵌光传送子网中执行保护倒换处理时检测的串联连接监测（TCM )层 变为失效；
所述将要传送到下游网元的信号， 指 ODU层失效处理后输出的正常的 ODUi信号或插入的 ODUi-AIS信号。
4、 如权利要求 1或 2或 3所述的开销修改方法， 其中，
所述会触发该内嵌光传送子网保护倒换的开销， 是分配给该内嵌光传送 子网的 TCMn-STAT开销 , 1≤n≤6；
所述外套子网有一个或多个， 其中最外层的外套子网为光传送子网或非 光传送子网， 如有其他外套子网， 所述其他外套子网均为光传送子网； 对其中的一个外套子网：
如该外套子网为光传送子网， 所述会触发该外套子网保护倒换的开销是 分配给该外套子网的 TCMn-STAT开销；
如该外套子网为非光传送子网， 所述会触发该外套子网保护倒换的开销 是 PM-STAT开销。
5、 如权利要求 4所述的开销修改方法， 其中，
所述将会触发所述外套子网保护倒换的开销的取值修改为不会触发所述 外套子网保护倒换的取值， 包括：
对于为光传送子网的外套子网， 是将 TCMn-STAT开销的取值修改为 3 比特的 011 , 100, 001 , 010中的一种;
对于为非光传送子网的外套子网， 是将 PM-STAT开销的取值修改为 3 比特的 000, 010, 011 , 100中的一种。
6、 如权利要求 1或 2或 3所述的开销修改方法， 其中，
所述设定的修改持续时间为该内嵌光传送子网发生保护倒换时可能引起 的最长业务瞬断时间。
7、 如权利要求 1或 2或 3所述的开销修改方法， 其中，
该内嵌光传送子网的网元只属于一个内嵌光传送子网； 或者
该内嵌光传送子网的网元同时属于多个内嵌光传送子网， 所述开销修改 方法中的该内嵌光传送子网指其中最内层的内嵌光传送子网。
8、 如权利要求 3所述的开销修改方法， 其中，
所述检测到该内嵌光传送子网中执行保护倒换处理时检测的 TCM层变 为失效， 包括： 检测到符合以下条件中的一种或多种：
该 TCM层的服务层变为失效；
该 TCM层变为 AIS、 连接锁定指示（LCK ) 、 连接断开指示（ OCI )或 串型连接丟失（LTC )状态。
9、 如权利要求 2所述的开销修改方法， 其中，
所述修改持续一段时间后， 取消所述修改， 包括： 设定的修改持续时间 到时， 取消所述修改； 或者
所述修改持续一段时间后， 取消所述修改， 包括： 如设定的修改持续时 间到时 ODU层还没有恢复正常， 取消所述修改； 及在所述设定的修改持续 时间内， 如检测到 ODU层恢复正常， 立即取消所述修改。
10、 如权利要求 3所述的开销修改方法， 其中，
所述修改持续一段时间后， 取消所述修改， 包括： 设定的修改持续时间 到时， 取消所述修改； 或者
所述修改持续一段时间后， 取消所述修改， 包括： 如设定的修改持续时 间到时 TCM层还没有恢复正常， 取消所述修改； 及在所述设定的修改持续 时间内， 如检测到 TCM层恢复正常， 立即取消所述修改。
11、 如权利要求 9或 10所述的开销修改方法， 其中，
所述修改持续一段时间后， 取消所述修改， 还包括： 在所述设定的修改 持续时间内，如检测到故障无法被该内嵌光传送子网的保护倒换系统恢复时， 立即取消所述修改。
12、 一种光传送网信号到非光传送网信号的转换方法， 应用于执行从光 传送网信号中解映射出非光传送网信号处理的网元中， 该网元所在网络包括 具有嵌套关系的内嵌光传送子网和外套非光传送子网， 该转换方法包括： 检测光通道数据单元信号（ ODUi )中 PM-STAT开销的取值是否为该内 嵌光传送子网网元对 PM-STAT开销修改后的不会触发该外套非光传送子网 保护倒换的取值：
如果是， 输出插入的第二非光传送网维护信号以替换从光传送网信号解 映射出的非光传送网信号；
如果否， 根据光通道净荷单元（OPU )层是否失效， 输出从光传送网信 号解映射出的非光传送网信号或插入的第一非光传送网维护信号；
其中， 所述第二非光传送网维护信号是不会触发非光传送网网元保护倒 换的非光传送网维护信号， 第一非光传送网维护信号是会触发非光传送网网 元保护倒换的非光传送网维护信号。
13、 如权利要求 12所述的转换方法， 其中，
该内嵌光传送子网网元对 PM-STAT开销修改后的不会触发该外套非光 传送子网保护倒换的取值， 为 3比特的 000, 010 , 011 , 100中的一种。
14、 如权利要求 12或 13所述的转换方法， 其中，
所述非光传送网信号是有物理编码子层 （PCS )编码的信号， 所述第二 非光传送网维护信号是没有数据帧且全是空闲帧的信号； 或者
所述非光传送网信号是同步数字体系（SDH)信号， 所述第二非光传送网 维护信号是净荷区全部为固定值且再生段和复用段开销正常的信号。
15、 一种防止嵌套的多个子网同时倒换的方法， 所应用的网络包括具备 保护倒换功能且直接嵌套的一对内嵌子网和外套子网， 其中的内嵌子网为光 传送子网， 该方法包括：
该内嵌子网的所有网元均执行权利要求 2的开销修改方法或执行权利要 求 2的任一从属权利要求中基于权利要求 2的开销修改方法； 或者， 该内嵌 子网中执行该内嵌光传送子网保护倒换切换的网元执行权利要求 3的开销修 改方法或执行权利要求 3的任一从属权利要求中基于权利要求 3的开销修改 方法；
设置该外套子网中执行保护倒换切换的网元的保护倒换延迟触发时间小 于对应内嵌子网发生保护倒换时可能引起的最长业务瞬断时间。
16、 如权利要求 15所述的方法， 其中，
该外套子网为光传送子网； 或者
该外套子网为非光传送子网， 所述方法还包括： 该网络中执行从光传送 网信号中解映射出非光传送网信号处理的网元执行如权利要求 12或 13或 14 所述的转换方法。
17、 如权利要求 16所述的方法， 其中， 该内嵌子网中没有嵌入其他的光传送子网； 或者
该内嵌子网中还嵌入有其他的光传送子网， 且该内嵌子网中执行该内嵌 光传送子网保护倒换切换的网元执行权利要求 3的开销处理方法或执行权利 要求 3的任一从属权利要求中基于权利要求 3的开销修改方法， 所述方法还 包括： 该内嵌子网中同时作为内嵌子网和外套子网的每一光传送子网中， 执 行该光传送子网保护倒换切换的网元均执行权利要求 3的开销修改方法或执 行权利要求 3的任一从属权利要求中基于权利要求 3的开销修改方法， 且执 行的开销修改方法中的该内嵌光传送子网指该光传送子网。
18、 如权利要求 15或 16或 17所述的方法， 其中，
该内嵌子网的所有网元均执行权利要求 2的开销修改方法或执行权利要 求 2的任一从属权利要求中基于权利要求 2的开销修改方法， 该外套子网中 执行保护倒换切换的网元不支持设置保护倒换延迟触发时间， 或将保护倒换 延迟触发时间设置为 0 , 或将保护倒换延迟触发时间设置为小于等于 5ms的 非零值； 或者
该内嵌子网中执行该内嵌光传送子网保护倒换切换的网元执行权利要求
3的开销修改方法或执行权利要求 3的任一从属权利要求中基于权利要求 3 的开销修改方法， 该外套子网中执行保护倒换切换的网元设置的保护倒换延 迟触发时间大于等于完成开销修改所需的时间且小于等于 10ms。
19、 一种内嵌光传送子网的网元中的开销修改装置， 包括修改控制单元 和开销修改单元， 其中：
所述修改控制单元， 设置为： 在检测到有故障发生时通知开销修改单元 修改开销， 其中， 该故障会触发该内嵌光传送子网及其中嵌入有该内嵌光传 送子网且具有保护倒换功能的外套子网保护倒换； 以及在修改持续一段时间 后， 通知开销修改单元取消修改， 该段时间小于等于设定的修改持续时间； 所述开销修改单元， 设置为： 在修改控制单元通知修改时， 将要传送到 下游网元的信号中会触发所述外套子网保护倒换的开销的取值修改为不会触 发所述外套子网保护倒换的取值， 且不修改会触发该内嵌光传送子网保护倒 换的开销； 以及在修改控制单元通知取消修改时， 取消所述修改。
20、 如权利要求 19所述的开销修改装置， 其中，
该开销修改装置应用于该内嵌光传送子网的所有网元中；
所述修改控制单元是设置为： 根据输入的光通道数据单元（ODU )层失 效指示信号、 用于指示开销是否可以修改的开销指示信号及设定的修改持续 时间信号， 输出修改指示信号， 其中， 该修改指示信号在 ODU层失效指示 信号指示 ODU层变为无效时， 指示修改被开销指示信号指示为可修改的会 触发对应外套子网保护倒换的开销且不修改被开销指示信号指示为不可修改 的会触发该内嵌光传送子网保护倒换的开销， 及在修改持续一段时间后， 通 知开销修改单元取消修改， 该段时间小于等于设定的修改持续时间；
所述开销修改单元是设置为： 根据所述修改指示信号的指示， 将输入的
ODUi告警指示信号（ ODUi-AIS信号）中会触发对应外套子网保护倒换的开 销的取值修改为不会触发所述外套子网保护倒换的取值且不修改会触发该内 嵌光传送子网保护倒换的开销，然后输出；及根据所述修改指示信号的指示， 取消所述修改。
21、 如权利要求 19所述的开销修改装置， 其中，
该开销修改装置应用于该内嵌光传送子网中执行该内嵌光传送子网保护 倒换切换的网元中， 还包括：
串联连接监测 （TCM )层失效检测单元， 设置为： 检测 ODU层失效处 理前的 ODUi信号中指定的 TCM层，并输出指示该 TCM层是否有效的 TCM 层失效指示信号， 其中， 该指定的 TCM层是被输入的 TCM层指示信号指示 为该内嵌光传送子网中执行保护倒换处理时检测的 TCM层；
所述修改控制单元是设置为： 根据输入的 TCM层失效指示信号、 用于 指示开销是否可以修改的开销指示信号及设定的修改持续时间信号， 输出修 改指示信号， 其中， 该修改指示信号在 TCM层失效指示信号指示 TCM层变 为无效时， 指示修改被开销指示信号指示为可修改的会触发对应外套子网保 护倒换的开销且不修改被开销指示信号指示为不可修改的会触发该内嵌光传 送子网保护倒换的开销， 及在修改持续一段时间后， 通知开销修改单元取消 修改， 该段时间小于等于设定的修改持续时间； 所述开销修改单元是设置为： 根据修改指示信号的指示， 将 ODU层失 效处理后输出的正常的 ODUi信号或插入的 ODUi-AIS信号中所述会触发对 应外套子网保护倒换的开销的取值修改为不会触发所述外套子网保护倒换的 取值且不修改所述会触发该内嵌光传送子网保护倒换的开销， 然后输出； 及 根据修改指示信号的指示， 取消所述修改。
22、 如权利要求 19或 20或 21所述的开销修改装置， 其中，
该内嵌光传送子网网元对应的外套子网有一个或多个， 其中最外层的外 套子网为光传送子网或非光传送子网， 如有其他外套子网， 所述其他外套子 网均为光传送子网；
所述修改控制单元指示的会触发该内嵌光传送子网保护倒换的开销是分 配给该内嵌光传送子网的 TCMn-STAT开销， l≤n≤6；
所述修改控制单元指示的会触发对应外套子网保护倒换的开销， 对其中 的一个外套子网， 如该外套子网为光传送子网， 会触发该外套子网保护倒换 的开销是分配给该外套子网的 TCMn-STAT开销； 如该外套子网为非光传送 子网， 会触发该外套子网保护倒换的开销是 PM-STAT开销。
23、 如权利要求 22所述的开销修改装置， 其中，
所述开销修改单元设置为： 将所述会触发对应外套子网保护倒换的开销 的取值修改为不会触发所述外套子网保护倒换的取值， 包括：
对于为光传送子网的外套子网， 是将 TCMn-STAT开销的取值修改为 3 比特的 011 , 100, 001 , 010中的一种；
对于为非光传送子网的外套子网， 是将 PM-STAT开销的取值修改为 3 比特的 000, 010, 011 , 100中的一种。
24、 如权利要求 19或 20或 21所述的开销修改装置， 其中，
该内嵌光传送子网的网元只属于一个内嵌光传送子网； 或者
该内嵌光传送子网的网元同时属于多个内嵌光传送子网， 所述修改控制 单元以其中最内层的内嵌光传送子网作为控制时所基于的该内嵌光传送子网。
25、 如权利要求 21所述的开销修改装置， 其中，
所述 TCM层失效检测单元设置为： 检测到该内嵌光传送子网中执行保 护倒换处理时检测的 TCM层变为失效， 包括： 检测到符合以下条件中的一 种或多种：
该 TCM层的服务层变为失效；
该 TCM层变为 AIS、 LCK、 OCI或 LTC状态。
26、 如权利要求 20或 21所述的开销修改装置， 其中，
所述修改控制单元设置为： 在修改持续一段时间后， 通知开销修改单元 取消修改， 包括：
所述修改控制单元在设定的修改持续时间到时， 通知开销修改单元取消 修改； 或者
所述修改控制单元在设定的修改持续时间到时如 ODU层或 TCM层还没 有恢复正常，通知开销修改单元取消修改；及在所述设定的修改持续时间内， 如 ODU层或 TCM层恢复正常， 立即通知开销修改单元取消修改；
其中， 所述设定的修改持续时间为该内嵌光传送子网发生保护倒换时可 能引起的最长业务瞬断时间。
27、 一种内嵌光传送子网的网元， 包括光通道数据单元（ODU )层失效 处理装置， 其中， 还包括开销修改装置， 其中：
所述开销修改装置釆用权利要求 20的开销修改装置或釆用权利要求 20 的任一从属权利要求中基于权利要求 20的开销修改装置；
所述 ODU层失效处理装置包括 ODU层失效检测单元和选择单元，其中：
ODU层失效检测单元，设置为：根据光通道数据单元信号（ODUi信号） 中的 ODU开销， 检测 ODU层是否失效， 并输出 ODU层失效指示信号到所 述开销修改装置和所述选择单元；
选择单元， 设置为： 在 ODU层失效指示信号指示 ODU层正常时， 输出
ODUi信号， 当 ODU层失效指示信号指示 ODU层失效时， 输出来自所述开 销修改装置的未经修改或修改后的 ODUi告警指示信号（ ODUi-AIS信号）。
28、一种内嵌光传送子网中执行该内嵌光传送子网保护倒换切换的网元， 包括光通道数据单元（ODU )层失效处理装置，其中，还包括开销修改装置， 所述开销修改装置釆用权利要求 21的开销修改装置或权利要求 21的任 一从属权利要求中基于权利要求 21的开销修改装置；
所述 ODU层失效处理装置设置为： 在 ODU层正常时， 输出正常的光通 道数据单元信号（ODUi信号）， 在 ODU层失效时， 输出插入以替换失效的 ODUi信号的 ODUi告警指示信号 （ ODUi-AIS信号） 。
29、 一种光传送网信号到非光传送网信号的转换装置， 应用于执行从光 传送网信号中解映射出非光传送网信号的网元中， 该网元所在网络包括具有 直接嵌套关系的内嵌光传送子网和外套非光传送子网， 该转换装置包括： 光通道数据单元信号（ODUi )解映射单元， 设置为： 从 ODUi信号中解 映射出非光传送网信号；
光通道净荷单元（OPU )层失效检测单元， 设置为： 根据 ODUi信号的 ODU和 OPU层开销， 判断 PM-STAT开销的取值是否为该内嵌光传送子网 网元对 PM-STAT开销修改后的不会触发该外套非光传送子网保护倒换的取 值， 及判断 OPU层是否失效， 并根据检测结果输出选择控制信号；
选择单元，设置为：根据所述选择控制信号，从输入的非光传送网信号、 第一非光传送网维护信号和第二非光传送网维护信号中选择一个输出；
其中， 所述第一非光传送网维护信号是会触发非光传送网网元保护倒换 的非光传送网维护信号， 第二非光传送网维护信号是不会触发非光传送网网 元保护倒换的非光传送网维护信号。
30、 如权利要求 29的转换装置， 其中，
所述 OPU层失效检测单元设置为：按照以下方式输出相应的选择控制信 号：
检测到 ODUi信号中的 PM-STAT开销取值等于对 PM-STAT开销修改后 的不会触发该外套非光传送子网保护倒换的取值时， 输出用于选择第二非光 传送网维护信号的选择控制信号； 检测到 PM-STAT开销取值不等于对 PM-STAT开销修改后的不会触发 该外套非传送子网保护倒换的取值且 OPU层失效时，输出用于选择第一非光 传送网维护信号的选择控制信号；
检测到 PM-STAT开销取值不等于对 PM-STAT开销修改后的不会触发 该外套非传送子网保护倒换的取值且 OPU层正常时，输出用于选择非光传送 网信号的选择控制信号。
31、 如权利要求 29或 30的转换装置， 其中，
所述 OPU层失效检测单元使用的不会触发该外套非光传送子网保护倒 换的取值为 3比特的 000, 010, 011 , 100中的一种；
且， 所述非光传送网信号是有物理编码子层（PCS )编码的信号， 所述 第二非光传送网维护信号是没有数据帧且全是空闲帧的信号； 或者， 所述非 光传送网信号是同步数字体系（SDH)信号， 所述第二非光传送网维护信号是 净荷区全部为固定值且再生段和复用段开销正常的信号。
32、 一种执行从光传送网信号解映射出非光传送网信号处理的网元， 包 括如权利要求 29或 30或 31所述的光传送网信号到非光传送网信号的转换装 置。
33、 一种包括具备保护倒换功能且直接嵌套的一对子网的网络， 其中的 内嵌子网为光传送子网， 其中，
该内嵌光传送子网中的所有网元均釆用如权利要求 27所述的网元，或者 , 该内嵌子网中执行该内嵌光传送子网保护倒换切换的网元釆用如权利要求 28所述的网元；
该外套子网中执行保护倒换切换的网元设置的保护倒换延迟触发时间小 于对应内嵌子网发生保护倒换时可能引起的最长业务瞬断时间。
34、 如权利要求 33所述的网络， 其中，
该外套子网为光传送子网； 或者
该外套子网为非光传送子网， 该网络中执行从光传送网信号中解映射出 非光传送网信号的网元釆用如权利要求 32所述的网元。
35、 如权利要求 33所述的网络， 其中，
该内嵌子网中没有嵌套其他的光传送子网； 或者
该内嵌子网中还嵌入有其他的光传送子网， 且该内嵌子网中执行该内嵌 光传送子网保护倒换切换的网元釆用如权利要求 28所述的网元，该内嵌子网 中同时作为内嵌子网和外套子网的每一光传送子网中， 执行该光传送子网保 护倒换切换的网元均釆用如权利要求 28 所述的网元且其中的开销修改装置 处理时以该光传送子网为内嵌光传送子网。
36、 如权利要求 33或 34或 35所述的网络， 其中，
该内嵌子网的所有网元均釆用如权利要求 27所述的网元，该外套子网中 执行保护倒换切换的网元不支持设置保护倒换延迟触发时间， 或将保护倒换 延迟触发时间设置为 0 , 或将保护倒换延迟触发时间设置为小于等于 5ms的 非零值； 或者
该内嵌子网中执行该内嵌光传送子网保护倒换切换的网元釆用如权利要 求 28所述的网元，该外套子网中执行保护倒换切换的网元设置的保护倒换延 迟触发时间大于等于完成开销修改所需的时间且小于等于 10ms。
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