JP2016005091A - Slave station communication device and optical communication network system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a slave station communication device and an optical communication network system that build a redundant system at lower costs.SOLUTION: The present invention relates to an optical communication network system comprising a master station communication device, and a slave station communication device for connecting with the master station communication device through a PON. The slave station communication device includes: a plurality of master station connection units capable of connecting the master station communication device with a plurality of logical links; a slave station side connection unit for connecting logical links enabled at the master station connection units with a slave station side network; and control means for having another master station connection unit switch any logical link of the master station connection units, and for having a switching destination master station connection unit connect with the master station communication device using a logical link after switching.

Description

  The present invention relates to a slave station communication apparatus and an optical communication network system, and can be applied to, for example, an optical communication network system using a configuration of E-PON (Ethernet (registered trademark) -Passive Optical Network).

  Conventionally, as a protection switching method for improving the reliability of an optical access network using a PON (Passive Optical Networks) configuration, a switching method based on redundancy of transmission lines is ITU-T GG. It is recommended (defined) in 983 (see Non-Patent Document 1).

  ITU-T G. In 983, as a PON protection switching method, a redundant configuration in which an active OLT (Optical Line Terminal) and a spare OLT are prepared as in Type B (see FIG. 10A), or Type C (see FIG. 10B) is used. As described above, a redundant configuration is recommended in which the OLT is made redundant and the ONU is prepared as a working system and a standby system.

  As a conventional technique for reducing the cost of PON construction using the conventional PON protection switching method, there is a technique described in Patent Document 1. In the system described in Patent Document 1, the same wavelength is assigned to all systems in the PON upstream communication, and the first system and the second system are multiplexed by the TDMA (Time Division Multiple Access) method. It is intended to reduce costs and achieve high reliability by communicating at different wavelengths for each system.

WO2010 / 0237

ITU-T Recommendation G. 983.1 IEEE 1904.1 Standard for Service Interoperability in Ethernet Passive Optical Networks (SIEPON)

  However, in the conventional redundant configuration of PON, in the configuration using two ONUs (Optical Network Units) of the active system and the standby system, the cost (equipment, installation location, power supply, etc.) of the two ONUs is reduced. The problem remains. For example, when a user constructs a redundant configuration by contracting two optical lines using PON, the user needs to purchase and maintain and operate two ONUs.

  Therefore, a slave station communication device (for example, ONU) and an optical communication network system that can form a redundant system at a lower cost are desired.

  According to a first aspect of the present invention, there is provided a slave station communication device connected to the master station communication device by a PON; (1) a plurality of master station connection units capable of connecting the master station communication device to a plurality of logical links; A slave station side connection section that connects the logical link that is valid in the master station connection section to the slave station side network; and (3) a logical link of any one of the master station connection sections is connected to the other master station And a control means for connecting to the master station communication device using the switched logical link to the master station connection unit of the switching destination.

  According to a second aspect of the present invention, in the optical communication network system including a master station communication device and a slave station communication device connected to the master station communication device by a PON, the slave station communication device of the first invention is applied. Features.

  According to the present invention, it is possible to provide a slave station communication device and an optical communication network system that realize a redundant system at a lower cost.

It is the block diagram shown about the functional structure of ONU which concerns on embodiment. It is the block diagram shown about the whole structure of the optical communication network system which concerns on embodiment. It is the block diagram shown about the internal structure of the PON control part which comprises ONU which concerns on embodiment. It is explanatory drawing shown about the state which ONU which concerns on embodiment is operate | moving normally. It is explanatory drawing shown about the state which the system switch generate | occur | produced at the time of abnormality in ONU which concerns on embodiment. It is an example of the MPCP connection sequence performed between ONU and parent station communication apparatus (OLT) which concerns on embodiment. It is the flowchart shown about operation | movement of ONU which concerns on embodiment. It is the flowchart shown about operation | movement of ONU which concerns on the modification of embodiment. It is the block diagram shown about the structure of ONU of the modification which concerns on embodiment. It is the block diagram shown about the example of the redundant structure of the conventional PON.

(A) Main Embodiment Hereinafter, an embodiment of a slave station communication device and an optical communication network system according to the present invention will be described in detail with reference to the drawings. Note that the slave station communication device and the master station communication device of this embodiment are ONU and OLT, respectively.

(A-1) Configuration of Embodiment FIG. 2 is a block diagram showing the overall configuration of the optical communication network system 1 of this embodiment.

  In the optical communication network system 1, a master station communication device 200 and n ONUs 100 (100-1 to 100-n) are arranged. Note that the number of ONUs 100 to be arranged is not limited.

  The communication protocol between the master station communication device 200 and the ONU 100 configuring the optical communication network system 1 and the specifications of each signal are not limited. However, in the following, as an example, an existing EPON system (for example, IEEE 802.3ah) is used. The PON system defined in IEEE 802.3av) is assumed to be applied.

  Further, an optical cable OC is connected to the master station communication device 200. The optical cable OC is branched into at least n × 2 by the optical splitter SP, and each of the branch destinations is connected to the ONUs 100-1 to 100-n by two.

  In FIG. 2, the master station communication device 200 is described as one component, but the internal configuration of the master station communication device 200 is not limited. For example, the master station communication device 200 may be configured using one OLT, or may be configured redundantly using two or more OLTs. In FIG. 2, the master station communication device 200 is illustrated as having one system optical cable OC connected thereto, but two systems of optical cables OC are connected to the master station communication device 200, and each system optical cable is connected. The OC branch destination may be connected to each ONU 100 (that is, the branch destination of the first optical cable OC and the branch destination of the second optical cable OC may be connected to the ONU 100). . That is, in the optical communication network system 1, the redundant configuration of components other than the ONU 100 (the number of OLTs configuring the master station communication device 200, the number of systems of the optical cable OC, etc.) is not limited.

  Next, the internal configuration of each ONU 100 will be described with reference to FIG. 1, FIG. 3, and FIG.

  The ONU 100 receives optical signals input from the PON interface or transmits optical signals to the PON interface, PON control units 103 and 104 that control user frames and control frames, and user networks It has a UNI (User Network Interface) unit 105 as a slave station connection unit that transmits and receives signals (user frames) from the (slave station side network), and a CPU 106 as a control unit that controls the entire apparatus. That is, in the ONU 100, two optical termination units and two PON control units are arranged.

  The two optical termination units 101 and 102 each terminate a branch destination (PON interface) of the optical cable OC. Hereinafter, the PON interfaces accommodated in the optical termination units 101 and 102 are represented as PIF1 and PIF2, respectively. The optical termination units 101 and 102 are connected to the PON control units 103 and 104, respectively.

  The PON control units 103 and 104 are each configured to accommodate two logical links.

  The user interface (UNI1, UNI2) is connected to the UNI unit 105. The UNI unit 105 is provided with ports 105a and 105b for accommodating these two interfaces (UNI1 and UNI2). As the user side interfaces (UNI1, UNI2), for example, various Ethernet (registered trademark) interfaces (1000Base-T, 10 GbE, etc.) can be applied.

  The UNI unit 105 can transmit and receive a frame on the user side for each logical link accommodated in the PON MACs 112 and 113 in association with one of the ports 105a and 105b (UNI1 and UNI2).

  In the following, in the ONU 100, the route (path through which the frame flows) related to the first logical link of the first PON control unit 103 is referred to as “route R1”, and the second logical link of the first PON control unit 103. The route related to (the path through which the frame flows) is “Route R2”, the route related to the first logical link of the second PON control unit 104 (the path through which the frame flows) is “Route R3”, and the second A route (path through which a frame flows) related to the second logical link of the PON control unit 104 is expressed as “route R4”.

  Next, the internal configuration of the PON control units 103 and 104 will be described with reference to FIG. It is assumed that the internal configurations of the PON control units 103 and 104 can be shown as shown in FIG.

  The PON control units 103 and 104 are respectively a PMA (Physical Medium Attachment) 109, a PCS (Physical Coding Sub-layer) 110, an RS (Reconciliation Sub-Slur 114), a PON MAC (PON Media 113R, 114) 116.

  The PCS 110 performs encoding for converting data to be transmitted into a bit string suitable for signalization.

  The PMA 109 performs conversion between a logical transmission bit string encoded by the PCS 110 and a signal string transmitted on the medium.

  The PON MACs 112 and 113 implement a frame transmission / reception method, a frame format, an error detection method, and the like.

  The RS 111 executes a preamble and LLID processing added to the MAC frame.

  The PON control units 103 and 104 include two (plural) PON MACs 112 and 113 and two (plural) UNIMACs 115 and 116, and are configured to accommodate two (plural) logical links. . In other words, since the PON control units 103 and 104 include two PON MACs 112 and 113, respectively, the entire ONU 100 can accommodate a total of four logical links. In addition, two logical link IDs and two MAC addresses are assigned to the two PON control units 103 and 104 in order to identify two lines (two PON interfaces). It is possible to control the combination.

  In this embodiment, as an example, the first PON MAC 112 configuring the first PON control unit 103 and the first PON MAC 112 configuring the second PON control unit 104 can be set to associate the same MAC address A1. It shall be. Also, it is assumed that the same MAC address A2 can be set to be associated with the second PON MAC 113 of the first PON control unit 103 and the second PON MAC 113 of the second PON control unit 104. In the ONU 100, during normal operation (a state in which no failure or the like has occurred), the PON control units 103 and 104 perform control to validate one of the MAC addresses. For example, in the normally operating ONU 100, when the first PON control unit 103 operates to validate the first MAC address A1, the second PON control unit 104 uses the second MAC address. It operates so that A2 becomes effective.

  In addition, the CPU 106 monitors each point in its own device and performs processing for detecting an abnormality (see FIG. 4). Specifically, the CPU 106 inputs / outputs the PON interface in the optical termination units 101 and 102 (monitoring point M1 in FIG. 4), the optical termination units 101 and 102 themselves (monitoring point M2 in FIG. 4), and the optical termination unit. Interface points (monitoring point M3 in FIG. 4) between the units 101 and 102 and the PON control units 103 and 104, the PON control units 103 and 104 themselves (the monitoring point M4 in FIG. 4), the UNI unit 105 and the PON control. Interface points (monitoring point M5 in FIG. 4) with the units 103 and 104 (first UNIMAC 115), and interface points (monitoring points in FIG. 4) between the UNI unit 105 and the PON control units 103 and 104 (second UNIMAC 116). Monitor M6).

  In the following, a control system configured by the first optical termination unit 101 and the first PON control unit 103 is configured by the first group G1, the second optical termination unit 102, and the second PON control unit 104. The control system to be performed is referred to as a second group G2. That is, in the ONU 100, the monitoring points M1 to M6 exist in each of the two groups G1 and G2. Therefore, the above-described routes R1 and R2 belong to the first group G1, and the above-mentioned routes R3 and R4 belong to the second group G1.

(A-2) Operation | movement of embodiment Next, operation | movement of the optical communication network system 1 of this embodiment which has the above structures is demonstrated. In the following, the internal operation of each ONU 100 in the optical communication network system 1 will be mainly described.

(A-2-1) Operation at Normal Time First, the operation of the ONU 100 at normal time (a state in which no failure has occurred) will be described.

  FIG. 4 is an explanatory diagram showing a state in which the ONU 100 is operating normally.

  In FIG. 4, the logical link using the first logical link ID1 (first MAC address A1) is valid in the first route R1 of the first group G1, and the first route R1 ( The logical link of the first logical link ID) is connected to UNI1. In FIG. 4, the logical link using the second logical link ID2 (second MAC address A2) becomes effective in the fourth route R4 of the second group G2, and the fourth route R4 ( The logical link of the fourth logical link ID) is connected to UNI2. In the state of FIG. 4, the logical links of the routes R2 and R3 are secured as spare logical links.

  As described above, the ONU 100 operates in a state in which one logical link is valid in each of the first PON control unit 103 and the second PON control unit 104 in a normal state.

(A-2-2) Operation when Abnormality Occurs Next, operations when an abnormality occurs in the ONU 100 will be described with reference to FIG.

  FIG. 5 illustrates a case where a failure occurs in the first PON control unit 103 (monitoring point M4) in the first group G1 after the ONU 100 starts operating normally (operating in the state of FIG. 4). Yes.

  In this case, the CPU 106 releases the connection (logical link) of the route R1, invalidates the first MAC address A1 used, and at the same time, associates the UNI unit 105 with the logic associated with UNI1 (port 105a). An instruction to switch the link to the route R3 of the second group G2 is given. It is assumed that the first MAC address A1 is valid on the logical link of the route R3 under the control of the CPU 106. Then, after that, the second PON control unit 104 responds to an inquiry (DiscoveryGate signal) periodically sent from the master station communication device 200 and raises the link of MPCP (Multi Point Control Protocol), and then OAM (Operation Administration And Maintenance), the link such as authentication is up, and the user frame is connected to the logical link of the route R3.

  In FIG. 5, the ONU 100 releases the logical link (the logical link using the first logical link ID and the first MAC address A1) set in the route R1, and moves toward the second group G2 side. A state after switching to the path R3 and further performing control for associating UNI1 (port 105a) with the logical link of the path R3 is shown.

  Note that the DiscoveryGate sequence between the ONU 100 and the master station communication device 200 (OLT) is, for example, as shown in the sequence diagram of FIG. The specific DiscoveryGate sequence applied between the ONU 100 and the master station communication device 200 (OLT) is not limited to that shown in FIG.

  When the ONU 100 releases the logical link set in the route R1, for example, the optical input of the optical terminal unit 101 (monitoring point M1) is shut down (if control is impossible, for example, ignore the next Then, the communication with the master station communication device 200 by the constituent elements (the first optical terminal unit 101 and the first PON control unit 103) on the first group G1 side may be performed. You may make it cancel. Then, the ONU 100 (CPU 106) controls the constituent elements (the second optical terminal unit 102 and the second PON control unit 104) on the second group G2 side to be switched to the first logic on the route R3. The logical link to which the link ID 1 is applied is validated. Then, the second PON control unit 104 responds to an inquiry (DiscoveryGate) periodically transmitted from the master station communication device 200 (OLT) and executes the connection sequence, so that the ONU 100 changes to FIG. As shown, reconnection based on MPCP can be performed with the master station communication device 200 using the logical link of the route R3 to which the first logical link ID1 is applied.

  At this time, the CPU 106 manages the MAC addresses to be set in the PON MACs 112 and 113 of the PON control units 103 and 104, and deletes the MAC address setting from the PON MAC to be invalidated (PON MAC related to the switching source route). Then, a process of attaching the MAC address of the switching source to the PON MAC to be validated (PON MAC related to the switching destination route) is performed.

  Accordingly, in the ONU 100, the identifier (MAC address and logical link) of the route R1 before switching and the identifier (MAC address and logical link ID) of the route R3 after switching are the same, so the master station communication device 200 ( On the OLT side), the logical link connection can be continued without being aware of the switching between the route R1 and the route R3 in the ONU 100. In the ONU 100, the logical link of the route R1 is invalidated and switched to the route R3, so that the components unique to the first group G1 that have been used (connected) (the first light) Since the termination unit 101 and the first PON control unit 103) are in a non-communication state, the power supply can be stopped to improve the power saving effect. Note that the ONU 100 also performs an operation of switching to the first group G1 when an abnormality occurs in the second group G2.

  When the operation of the ONU 100 as described above is generalized, for example, it can be shown by a flowchart of FIG. In the following, the operation when an abnormality is detected at one of the monitoring points of the groups G1 and G2 from the state in which the ONU 100 is operating normally (the state in FIG. 4) will be described using the flowchart in FIG.

  In the ONU 100, after normal operation is started, monitoring is performed by the CPU 106 until an abnormality is detected in only one of the groups (S101 to S103).

  When an abnormality is detected only in the first group G1 (step S101: Yes, step S103: No), the CPU 106 disconnects the logical link of the first group G1 (the logical link of the route R1). Then, the optical terminal units 101 and 102, the PON control units 103 and 104, and the UNI unit 105 are controlled so as to switch to the spare logical link of the second group G2 (the logical link of the route R3) (S104, S105). ). In the second group G2 of the ONU 100, after the logical link is switched, a connection sequence such as MPCP is executed in response to an inquiry (DiscoveryGate signal) from the master station communication device 200, and a spare logical link (route R3) is connected. The connection switching to the logical link) (switching of the connection using the first MAC address A1 and the first logical link ID1) is completed (S106).

  On the other hand, when an abnormality is detected only in the second group G2 (step S101: No, step S102: Yes), the CPU 106 determines the logical link of the second group G2 (the logical link of the route R4). The optical terminal units 101 and 102, the PON control units 103 and 104, and the UNI unit 105 are controlled so as to be disconnected and switched to the spare logical link (the logical link of the route R2) of the first group G1 (S107). , S108). In the first group G1 of the ONU 100, after the logical link is switched, a connection sequence is executed in response to an inquiry (DiscoveryGate signal) from the master station communication device 200, and a spare logical link (logical link of the route R2). The connection switching to (the connection switching using the second MAC address A2 and the second logical link ID2) is completed (S109).

  As described above, the ONU 100 includes a master station connection unit (a group including one optical terminal unit and one PON control unit) that can be connected to the master station communication device 200 (OLT) using a plurality of logical links. There are several. Then, the ONU 100 switches the logical link of the master station connection unit (group) in which an abnormality has been detected to the logical link of another normal master station connection unit (group), and connects to the master station communication device 200 (OLT). It is the composition which makes it.

(A-3) Effects of Embodiment According to this embodiment, the following effects can be achieved.

  The ONU 100 includes a plurality of master station connection units (a group constituted by one optical terminal unit and one PON control unit) that can be connected to the master station communication device 200 (OLT) using a plurality of logical links. Then, the ONU 100 switches the logical link of the master station connection unit in which the abnormality is detected to another normal (logical link in which no abnormality is detected) master station connection unit (backup logical link), and performs the master station communication. By connecting with the device 200 (OLT), a redundant configuration function can be realized in the ONU 100. As a result, the ONU 100 can always provide communication for two lines while forming a redundant system in the apparatus. That is, by applying the ONU 100, it is possible to realize an economical ONU protection function at a low cost. For example, when a redundant configuration is realized with a conventional ONU, it is necessary to prepare two ONUs, which costs two units. However, if an ONU 100 of this embodiment is used, even if an abnormality occurs, Therefore, it is possible to realize a redundant configuration function in the apparatus and to always provide communication for two lines.

  Further, in the ONU 100, by realizing the redundant configuration of the first group G1 and the second group G2, even if an abnormality occurs in one of the groups, the route R1 and the route R3 or the route By setting the MAC addresses of R2 and R4 to the same value and adopting a two-line logical link configuration within the group, the control on the master station communication device 200 side (OLT side) is not complicated, and the same line is The connected operation is performed and both lines are guaranteed.

(B) Other Embodiments The present invention is not limited to the above-described embodiments, and may include modified embodiments as exemplified below.

  (B-1) In the ONU 100 of the above embodiment, when one logical link is connected to one PON control unit / optical termination unit and an abnormality occurs in the system, the other PON control unit / optical The method for switching to the termination unit has been described, but if m logical links (m is an integer of 3 or more) are connected to one PON control unit / optical termination unit, it is possible to switch m at the same time. It is.

  In the above-described embodiment, a configuration in which two sets of master station connection units (a group including one optical termination unit and one PON control unit) are arranged in one ONU 100 has been described. It is also possible to arrange three or more master station connection units in the network so that the backup logical links can be switched with each other.

  (B-2) In the ONU 100 of the above embodiment, an example in which a monitoring point is prepared for each group and switching to another normal group when an abnormality occurs is shown. However, the CPU 106 installed in the ONU 100 is shown. It is also possible to connect the logical link by forcibly switching the selection of the UNI unit 105 to another route at any timing from the (control unit).

  For example, in the ONU 100 of the above-described embodiment, an example of an operation when the selection of the UNI unit 105 is forcibly switched to another route (switched to a logical link of another route) at an arbitrary timing is shown in the flowchart of FIG. Will be described. When the CPU 106 starts forcible switching (the switching source route and the switching destination route are set in the CPU 106 in advance), it is checked whether there is a failure in the group including the switching destination route (S201). ), Start switching when there is no failure (when no abnormality is detected). In this case, the CPU 106 disconnects the logical link of the switching source route, and causes the UNI unit 105 to perform link switching to the switching destination route (S202, S203), and the PON control unit of the switching destination group performs parent switching. A connection with the local communication device (OLT) is executed (MPCP link-up triggered by the DiscoveryGate from the OLT) (S204).

  The means for setting the switching source and the switching destination in the CPU 106 is not limited, and may be executed according to control (control by a maintenance person or the like) from an external console terminal (not shown). You may make it perform based on the schedule programmed beforehand.

  (B-2) In the above embodiment, the PON control units of a plurality of groups are connected to one UNI unit 105, but the UNI unit 105 itself is divided into a plurality of units as shown in FIG. (In FIG. 9, they are illustrated as 105-1 and 105-2).

  Furthermore, the UNI unit 105 (105-1, 105-2), the PON control unit (103, 104), and the optical terminal unit (101, 102) are modularized (parts that are removable from the ONU 100 main body). Therefore, it is possible to divide the replacement target at the time of failure and perform maintenance while operating without replacing the entire ONU 100.

  For modularization of the optical termination unit of the ONU, an interface of industry standards such as SFP and SFP +, so-called MSA (Multi Source Agreement), may be used.

  DESCRIPTION OF SYMBOLS 1 ... Optical communication network system, 200 ... Master station communication apparatus (OLT), OC ... Optical cable, 101, 102 ... Optical termination part, 103, 104 ... PON control part, 105 ... UNI part, 105a, 105b ... Port, 106 ... CPU, 100, 100-1 to 100-n ... ONU, 101, 102 ... Optical termination unit, 103, 104 ... PON control unit, 109 ... PMA, 110 ... PCS, 111 ... RS, 112, 113 ... PONMAC, 114 ... BRIDGE, 115, 116 ... UNIMAC, 105 ... UNI section, 106 ... CPU.

Claims (7)

In the slave station communication device connected to the master station communication device by PON,
A plurality of master station connection units capable of connecting the master station communication device and a plurality of logical links;
A slave station side connection section that connects the logical link that is enabled in the master station connection section to the slave station side network; and
Switch the logical link of any of the parent station connection units to the other parent station connection unit, and connect to the parent station communication device using the switched logical link to the parent station connection unit of the switching destination And a slave station communication device. It further comprises monitoring means for performing monitoring related to each of the above-mentioned master station connection units,
The control means switches the logical link of the master station connection section in which an abnormality is detected by the monitoring means to the other master station connection section, and switches the logical link after switching to the master station connection section of the switching destination. The slave station communication apparatus according to claim 1, wherein the slave station communication apparatus is connected to the master station communication apparatus using a network.   The control means forcibly switches the logical link of the master station connection section in which no abnormality is detected by the monitoring means to the other master station connection section, and switches to the master station connection section of the switching destination. 3. The slave station communication device according to claim 2, wherein the slave station communication device is connected to the master station communication device using a later logical link.   4. The slave station communication apparatus according to claim 3, wherein the slave station side connection section is configured by using a plurality of slave station side connection modules for connecting to the slave station side network.   The slave station communication apparatus according to claim 4, wherein the slave station side connection module and the master station connection section are detachably attached to the slave station communication apparatus main body.   Each of the master station connection units is divided into an optical termination module that terminates a PON optical cable connected to the master station communication device, and a PON control module that performs communication using a logical link with the master station communication device. The slave station communication device according to claim 5, wherein   In an optical communication network system comprising a master station communication device and a slave station communication device connected to the master station communication device by a PON, the slave station communication device according to any one of claims 1 to 6 is used as the slave station communication device. An optical communication network system characterized by being applied.

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