JP3546814B2 - ATM device and ATM communication network - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ATM device such as an ATM switch exchange-connected in an ATM (Asynchronous Transfer Mode), and in particular, performs connection setting in a detour connection such as a line failure between ATM devices constituting an ATM communication network (network). The present invention relates to an ATM device, a connection setting method thereof, and an ATM communication network.
[0002]
[Prior art]
In general, among service categories in ATM, CBR (Constant Bit Rate) is a class that handles important data or real-time moving image / audio data because it is always transmitted at a constant rate. VBR (Variable Bit Rate) is a variable bit rate. However, in order to guarantee the bandwidth of SCR (Sustainable Cell Rate: average cell rate), which is one of the traffic parameters, real-time variable rate video / audio is used. And LAN data. ABR (Available Bit Rate) is a class used when handling LAN (Local Area Network) application data or when traffic fluctuations are severe in order to secure a data rate appropriately in accordance with network congestion by feedback control. UBR (Unspecified Bit Rate) is a class that handles data that can be communicated someday because there is no bandwidth allocation and no quality assurance regulations. Conventionally, these classes are set according to the application, and data communication is performed between ATM devices.
[0003]
[Problems to be solved by the invention]
The above-described conventional class is not a traffic class that fully considers network detour. Further, at present, the unit price per band is high, and the user actually tries to cut down the band as much as possible. In such a situation, a backup band must be secured in order to cope with the failure, and effective utilization of the band is desired.
[0004]
An object of the present invention is to reduce the bandwidth which must be ensured at the time of a detour connection in the event of a failure, and to assure variable bit data (b-VBR) instead to ensure transmission of important CBR data. An object of the present invention is to provide an ATM device, a connection setting method thereof, and an ATM communication network capable of performing signaling while keeping the upper limit of the average rate to be low.
[0005]
[Means for Solving the Problems]
An ATM device according to the present invention includes an input interface unit for terminating an input line and interfacing with the inside of the device, an output interface unit for terminating an output line and interfacing with the inside of the device, and the input interface unit. An ATM switch for outputting an ATM cell input from the ATM switch to a predetermined output side by hardware switching, a storage unit for storing various data for device operation and a call processing program, a central control unit, A switch control unit configured to perform connection setting release control based on a call process of the control unit; and an input unit configured to perform a data setting input operation corresponding to the connection between the devices, wherein the central control unit includes the input unit. Predetermined traffic class information for each connection between devices of the ATM communication network based on data input from the communication unit A traffic parameter setting unit for setting transmission and reception rate information, a failure determination unit for detecting the failure, and the storage unit for determining whether the traffic class information of the failed connection is a specific class in consideration of detour. A traffic class identification unit for referring to and identifying data stored in advance, and a parameter indicating an upper limit of an average rate guaranteed for normal use when the traffic class is identified as the specific class by the traffic class identification unit. A traffic parameter changing unit for changing a parameter indicating the upper limit of the guaranteed average rate for the detour, a setup message generating unit for generating a setup message, and a variable length information element of the setup message generated by the setup message generating unit The traffic para And a setup message transmitting / receiving unit that sends the designated parameter changed by the data changing unit to the ATM device to be bypassed, and applies to each connection between the devices of the ATM communication network based on the data read from the storage unit. Setting of traffic class information and transmission / reception rate information to be performed and call processing according to reception information from a partner apparatus using the call processing program. When the apparatuses are in a normal state, a variable length of a connection setup message is set. Traffic class information for handling non-real-time data in which detour is considered in an information element, first transmission / reception rate information indicating an upper limit of an average rate guaranteed in a normal state corresponding to the traffic class information, and an upper limit of a transmission rate that can be transmitted And sending and receiving third transmission / reception rate information indicating The connection setting is performed, and when a failure between the devices is detected, the traffic class information that handles non-real-time data in consideration of the detour in the variable length information element of the connection setting setup message and the detour corresponding to the traffic class information are performed. The second transmission / reception rate information indicating the upper limit of the guaranteed average rate at the time and the third transmission / reception rate information indicating the upper limit of the transmission rate that can be transmitted are inserted and transmitted to set up the connection between the devices. .
[0008]
The ATM communication network of the present invention is constructed using the above-described ATM device.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0010]
Referring to FIG. 1, one of a plurality of ATM devices constituting an ATM communication network is shown. An ATM device 1 includes an input interface unit 2 for terminating an input line and interfacing with the inside of the device. An output interface section 3 for terminating an output line and interfacing with the inside of the apparatus, an ATM switch 4 for outputting an ATM cell input from the input interface section 2 to a predetermined output side by hardware switching, and an apparatus. A storage unit 5 for storing various data for operation and a call processing program, and traffic class information and transmission / reception rate information applied to each connection between the devices of the ATM communication network based on the data read from the storage unit 5 The call processing is performed and call processing is performed according to the received information from the partner apparatus using a call processing program. When the devices are in the normal state, the traffic class information handling non-real-time type data taking into account the detour and the average rate guaranteed in normal times corresponding to this traffic class information are included in the variable length information element of the connection setup message. A central control unit 6 for inserting and transmitting first transmission / reception rate information indicating an upper limit and third transmission / reception rate information indicating an upper limit of a transmittable transmission rate and setting a connection between devices, and call processing of the central control unit 6 A switch control unit 7 for performing connection setting / release control based on the data, and an input unit 8 for performing a data setting input operation corresponding to the connection between the devices. When detecting a failure between the ATM devices, the central control unit 6 responds to the traffic class information handling non-real-time data in consideration of the detour in the variable length information element of the connection setup message and the traffic class information. The second transmission / reception rate information indicating the upper limit of the guaranteed average rate at the time of detouring and the third transmission / reception rate information indicating the upper limit of the transmission rate that can be transmitted are inserted, and the connection between the devices is set.
[0011]
The central control unit 6 includes a traffic parameter setting unit 61 for setting predetermined traffic class information and transmission / reception rate information for each connection between devices of the ATM communication network based on data input from the input unit 8, And a traffic class identification unit 63 that identifies whether the traffic class information of the failed connection is a specific class in consideration of detour by referring to data stored in the storage unit 5 in advance. From the parameter indicating the upper limit of the guaranteed average rate for normal time when the traffic class is identified as the specific class by the traffic class identification unit 63, the parameter indicating the upper limit of the guaranteed average rate for detour is changed. A traffic parameter changing unit 64 to be changed, and a set to generate a setup message. An up message generation unit 65 and a setup message transmission / reception unit 66 for sending the variable length information element of the setup message generated by the setup message generation unit 65 to the ATM device to be detoured by inserting the designated parameter changed by the traffic parameter change unit 64 And
[0012]
The ATM device 1 transmits the signaling information of the connection setting in the setup message. In this connection setting, the well-known variable length information element of the setup message contains first transmission / reception rate information (g- SCR), second transmission / reception rate information (d-SCR) indicating the upper limit of the average rate guaranteed at the time of detour, and third transmission / reception rate information (PCR) indicating the upper limit of the transmission rate that can be transmitted. The connection setting is performed by using the first and third transmission / reception rate information and using the second and third transmission / reception rate information in the setup message during the detour.
[0013]
In a setup message used for connection setting, an ATM traffic class, which is one of information of a variable length information element (Information Element: IE), is converted to a conventional Constant Bit Rate (CBR) or a real-time Variable Bit Rate (rt-VBR). ), Nrt-VBR (non-real-time Variable Bit Rate), ABR (Available Bit Rate), UBR (Unspecified Bit Rate), and a class b-VBR that handles non-real-time data in consideration of a detour at the time of failure. (Bridly Variable Bit Rate) is newly defined.
[0014]
Generally, traffic classes handling non-real-time data are rt-VBR and nrt-VBR. The rt-VBR and the nrt-VBR include a peak cell rate (PCR) indicating the upper limit of a transmission rate that can be transmitted on the ATM connection, and a CDVT (cell delay) which is a parameter indicating how much a change in a continuous cell transfer interval is allowed. Variation Tolerance), SCR (Sustainable Cell Rate) indicating the upper limit of the guaranteed average rate of the ATM connection, and BT (Burst Tolerance) which is a parameter for determining the number of cells that can be continuously transmitted at the peak rate are set. Is sent.
[0015]
Here, the b-VBR data newly defined this time includes a peak cell rate (PCR), a cell delay variation tolerance (CDVT), a burst tolerance (BT), and a g-value indicating the upper limit of a guaranteed average rate in a normal state. An SCR (defined as General Sustainable Cell Rate) and a d-SCR (defined as detour Sustainable Cell Rate) indicating the upper limit of the average rate guaranteed during detour are set. In the normal setting of the connection setting, the signaling information is transmitted by the g-SCR for the b-VBR class data to establish the connection, and when the detour connection is established, the signaling is performed by the d-SCR.
[0016]
Here, the transmission / reception rate of the b-VBR data controls the inside of the ATM device such that the g-SCR is switched to the d-SCR for signaling during detour. In the network, a setup packet containing such information is transmitted to the node as connection setting signaling information, and a connection is established.
[0017]
Next, the operation will be described with reference to FIG. First, traffic class information and transmission / reception rate information (traffic parameters) are set for each connection between ATM devices constituting an ATM communication network (step 1: abbreviated as S1). When it is detected that a failure has occurred in a line or the like (S4) in a state where the connection with the partner ATM device has been established and established (S2, S3), the traffic class information set in the connection considers the detour. If it is identified that the class handles the non-real-time data (S5), the parameter indicating the upper limit of the average rate at which the transmission / reception rate information is guaranteed is changed from g-SCR to d-SCR (S6). The changed parameters and the traffic class information are put into the variable length information element of the setup message and transmitted to the bypass target ATM device (S7), and the connection is set (S8).
[0018]
Next, FIG. 3 shows an example of an ATM network configuration. As a premise, regarding the connection setting, the communication (1) between the ATM devices A and B is performed by setting VP (Virtual Pass) = A, VC (Virtual Channel) = a1 (CBR), a2 (b-VBR), a3 (b-VBR). VP = B, VC = b1 (CBR), b2 (CBR), b3 (b-VBR) for communication between ATM devices A and C, and VP = for communication between ATM devices B and C (3) C, VC = c1 (CBR), c2 (b-VBR), and c3 (b-VBR). Regarding the setting of the port of the ATM device, the parameters of CBR, b-VBR, (ABR, UBR) (CBR, PCR, CDVT, b-VBR, PCR, CDVT, g-SCR, d-SCR, BT) are set.
[0019]
Next, the connection setting operation of the ATM device will be described.
[0020]
The ATM device transmits a request for setting the connection to the ATM switch in a setup message. The setup message contains various types of information, identifies the version of the signaling using the protocol identifier, and identifies the connection to be set up using the call identifier. The destination address, own address, required quality, and the like are contained in a variable length information element (IE).
[0021]
The IE includes AAL parameters indicating AAL identification (AAL1 to AAL5) and AAL PDU size, ATM traffic descriptor indicating connection transmission / reception rate (PCR / g-SCR, d-SCR Burst size), and point-to-point. Broadband bearer capability indicating multipoint, CBR / rt-VBR / nrt-VBR / b-VBR / ABR / UBR indicating a traffic class, and Broadband indicating higher-level protocol information (for example, address and socket number) using ATM. Broadband information indicating a high layer information and a protocol identifier (for example, IP or OSI layer 3) of an upper protocol using ATM. aer Information, Called party address indicating a destination ATM address, Called party subaddress indicating a destination sub-ATM address, Calling party address indicating a source ATM address, and Calling address / subscription address indicating a source sub-address. Connection identifier indicating the VCI, Quality of Service parameter indicating the required quality of ATM transfer time such as cell discard and delay, Transit network selection indicating the specification of a relay network, and End indicating the identifier of each leaf for point multipoint. point reference, etc. .
[0022]
The ATM device receives this and determines a route to the destination. Further, it is determined whether or not the required quality is satisfied, and a resource is reserved. When the connection is thus set, the VPI / VCI is first returned to the user terminal by CALL PROCEEDING, and the connection message is notified by a CONNECT message. At this time, the ATM traffic descriptor is signaled by g-SCR for b-VBR data.
[0023]
In FIG. 3, when a detour occurs between ATM devices (between A and B) due to a failure or the like, a connection of a detour (between A and C) is newly established by signaling a setup message by the PNNI protocol. At this time, when the transmission / reception rate information included in the ATM traffic descriptor of the IE is normal, what was signaled by g-SCR and PCR is signaled by detour d-SCR and PCR to establish a connection.
[0024]
Here, since the parameter indicating the upper limit of the guaranteed average rate in the transmission / reception rate information of the ATM traffic class b-VBR data is changed from g-SCR to d-SCR and the connection is established, the VP after the bypass = B represents the d-SCR of VC = z1 (= a1), which is the CBR data on the side where the detour has occurred due to a failure, etc., and VC = z2 (= a2), z3 (= a3), which is b-VBR data. The band and the d-SCR band of VC = b1, b2, which is the CBR data on the side where the connection has been established before the detour is performed, and VC = b3, which is the b-VBR data, are guaranteed ( In the design stage, the band of VP = B is set to be equal to or more than the total value of the guaranteed band after the bypass. Similarly, also for VP = C between B and C, the b-VBR data is signaled by d-SCR and the band is secured.
[0025]
For example, in FIG. 3, when the SCR of a1 and a2 (= g-SCR) and the SCR of a3 (= g-SCR) are each 1 Mbps, (1) sets a detour to (2) due to a line failure or the like. Conventionally, a bandwidth of 3 Mbps, which is the sum of the SCR of a1 and a2 (= g-SCR) and the SCR of a3 (= g-SCR), was the minimum required as a band to be guaranteed. According to the above, 1 Mbps of a1 guarantees the entire band because of CBR, and a2 and a3 guarantee the band only for d-SCR at the time of detour by b-VBR, that is, lower the upper limit of the guaranteed average rate, If the d-SCR of a2 and the d-SCR of a3 are respectively set to 0.5 Mbps, the total of the bandwidth required only at the time of detour and required to be secured at a minimum may be 2 Mbps. That. That is, priority is given to ensuring transmission of important CBR data, and instead, signaling is performed by lowering the upper limit of the guaranteed average rate of b-VBR, and connection is established.
[0026]
Since the SCR of the conventional VBR data (rt-VBR, nrt-VBR) and the g-SCR of the b-VBR data defined this time are equivalent (the circuit is designed in such a manner), the signaling function of the present invention is used. Can also be connected to an ATM device that does not have a. In this case, since the d-SCR for detour cannot be used, the service is the same as the conventional one.
[0027]
【The invention's effect】
As described above, according to the present invention, the d-SCR, which is the upper limit of the guaranteed average rate for b-VBR data at the time of detour, can be set lower than the g-SCR at normal time. Can be kept as low as possible. Also, since the connection request is made by the connection setting unit of the transmitting ATM terminal and the switch, the system can be realized only by changing the connection setting unit.
[Brief description of the drawings]
FIG. 1A is a configuration diagram showing an embodiment of an ATM device of the present invention. FIG. 2B is a diagram illustrating a configuration of a central control unit in FIG.
FIG. 2 is a flowchart showing the operation of the embodiment of the present invention.
FIG. 3 is a diagram illustrating an example of a connection at the time of detour;
[Explanation of symbols]
Reference Signs List 1 ATM device 2 Input side interface unit 3 Output side interface unit 4 ATM switch 5 Storage unit 6 Central control unit 7 Switch control unit 8 Input unit 61 Traffic parameter setting unit 62 Failure determination unit 63 Traffic class identification unit 64 Traffic parameter change unit 65 Setup message generator 66 Setup message transmitter / receiver

Claims (2)

An input interface unit for terminating an input line and interfacing with the inside of the device, an output interface unit for terminating an output line and interfacing with the inside of the device, and an ATM cell input from the input interface unit. An ATM switch for outputting to a predetermined output side by hardware switching, a storage unit for storing various data for operating the device and a call processing program, a central control unit, and a call processing of the central control unit. A switch control unit for performing setting release control of the connection, and an input unit for performing a data setting input operation corresponding to the connection between the devices, wherein the central control unit receives data input from the input unit. Predetermined traffic class information and transmission / reception rate information for each connection between devices of the ATM communication network based on the A traffic parameter setting unit to be set, a failure determination unit for detecting the failure, and data stored in advance in the storage unit as to whether the traffic class information of the failed connection is a specific class in consideration of detour. A traffic class identification unit for identifying and referring to a parameter indicating the upper limit of the average rate guaranteed for normal time when the traffic class is identified as the specific class by the traffic class identification unit. A traffic parameter changing unit for changing to a parameter indicating an upper limit of a guaranteed average rate, a setup message generating unit for generating a setup message, and changing the traffic parameter to a variable length information element of the setup message generated by the setup message generating unit. Changed by department A set-up message transmitting / receiving unit for transmitting fixed-parameter parameters to the detour-targeted ATM device, and based on data read from the storage unit, traffic class information applied to each connection between the devices of the ATM communication network and transmission / reception Set the rate information and perform call processing according to the received information from the partner device using the call processing program. When the devices are in a normal state, consider the bypass in the variable length information element of the connection setup message. Class information handling the non-real-time type data, first transmission / reception rate information corresponding to the traffic class information and indicating an upper limit of an average rate guaranteed in a normal state, and a third transmission / reception rate indicating an upper limit of a transmission rate that can be transmitted Sends information and sets connection between devices Therefore, when a failure between the devices is detected, the variable length information element of the connection setup message handles the traffic class information that handles non-real-time data in consideration of the detour and the traffic class information corresponds to the traffic class information. An ATM device comprising: transmitting and receiving second transmission / reception rate information indicating an upper limit of an average rate and third transmission / reception rate information indicating an upper limit of a transmission rate at which transmission is possible; An ATM communication network, wherein a communication network is constructed using the ATM device according to claim 1.

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