JP3666472B2 - ATM network and network management method used therefor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ATM network and a network management method used therefor, and more particularly, to a method for avoiding communication failure due to a SVC (Switched Virtual Connection) in a LAN (Local Area Network) emulation network.
[0002]
[Prior art]
Conventionally, in an ATM (Asynchronous Transfer Mode) network, a one-to-one connection type communication is fundamental, and therefore a connectionless type existing LAN [Ethernet (R) or FDDI (Fiber) with a broadcast function is used. Application that has been used in [Distributed Data Interface) etc.] cannot be moved as it is.
[0003]
Therefore, LAN emulation that emulates an existing LAN and executes communication on ATM is standardized by the ATM Forum. In the LAN emulation 1.0 specification, the bandwidth and QoS (Quality of Service) corresponding to the application, which is a feature of ATM, cannot be controlled, but in the LAN emulation 2.0 specification, QoS control for each communication path is possible. Yes.
[0004]
The LAN emulation components include four types of nodes / functions: LEC (LAN Emulation Client), LES (LAN Emulation Server), LECS (LAN Emulation Configuration Server), and BUS (Broadcast and Unknown Server).
[0005]
The LEC is a client function that executes registration and acquisition of an ATM address and a MAC (Media Access Control) address, sends its own address to the LES, and registers the address.
[0006]
The LES is a server that performs address resolution between a MAC address and an ATM address, and creates an address table based on the MAC address and ATM address that each LEC has declared to the LES.
[0007]
The LECS is a server with which the LEC communicates first, and responds to an inquiry from the LEC with the ATM address of the LES. BUS is a function for realizing broadcast and multicast of an existing LAN. When broadcast data received by the LEC from the LAN side or broadcast data sent by itself is transferred, these data are registered. Send to all LECs.
[0008]
[Problems to be solved by the invention]
In the conventional LAN emulation environment described above, when disconnection from the LES occurs, all the SVCs must be once released and reconnected from the reconnection with the LES.
[0009]
Therefore, if only the SVC between a certain LEC is disconnected due to a momentary disconnection, etc., it is only necessary to redo the opening of that SVC. However, if the SVC with the LES is disconnected, It is necessary to reopen SVC, and the load is further increased.
[0010]
Accordingly, an object of the present invention is to solve the above-described problems and provide an ATM network capable of performing communication between LECs even when an SVC with LES is momentarily interrupted, and a network management method used therefor.
[0011]
[Means for Solving the Problems]
An ATM network according to the present invention includes an ATM (Asynchronous Transfer Mode) address and a MAC (Media Access Control) address registration / acquisition LEC (LAN Emulsion Client) and an address resolution between the MAC address and the ATM address. An ATM network that executes LAN (Local Area Network) emulation using LES (LAN Emulation Server) that executes
SVC (Switched Virtual Connection) opened at least between the LEC using an extended message exchanged between the LEC and the LES is retained when an SVC disconnection between the LES and the LEC occurs. With means,
When the SVC disconnection occurs using the held SVC, communication between the LECs can be continued.
[0012]
The network management method according to the present invention includes an ATM (Asynchronous Transfer Mode) address and a MAC (Media Access Control) address registration / acquisition LEC (LAN Emulsion Client), and an address resolution between the MAC address and the ATM address. A network management method for an ATM network that performs LAN (Local Area Network) emulation using LES (LAN Emulation Server) that executes
SVC (Switched Virtual Connection) established at least between the LEC using an extended message exchanged between the LEC and the LES is also retained when an SVC disconnection between the LES and the LEC occurs. And the step of continuing communication between the LECs even when the SVC disconnection occurs using the held SVC.
[0013]
In other words, the ATM network of the present invention extends the message with LES (LAN emulation server) for communication between LEC (LAN emulation client) during execution of LAN (Local Area Network) emulation, and between LES and LEC. Even when an SVC (Switched Virtual Connection) disconnection occurs, the SVC established between the LECs is retained, and communication between the LECs can be continued.
[0014]
More specifically, in the ATM network of the present invention, the SVC can be held between LECs by extending the JOIN message, so that communication between LECs is possible even if the SVC with LES is momentarily interrupted. Yes.
[0015]
The extension of the JOIN message is a time for holding the SVC between the LEC and LE_ARP (information on correspondence between the MAC address and the ATM address) when the SVC disconnection with the LES occurs in the JOIN request for the LEC to join the network ( (Hereinafter referred to as “KEEP TIMER”), and when the LES side supports KEEP TIMER, it is performed by returning a JOIN response with the time added.
[0016]
In addition, in the present invention, if reconnection with the LES can be performed within the KEEP TIMER time, the REGISTER request for registering the LE_ARP of the proxy and the LE_ARP resolution of the BUS (Broadcast and Unknown Server) are not required, and the processing is simplified. The
[0017]
In other words, in the present invention, by maintaining the SVC between the LECs, it is possible to avoid the inability to communicate with the LES due to the SVC instantaneous interruption, and when reconnecting from the SVC instantaneous interruption, the LECS is directly connected to the LES. Therefore, the processing can be simplified as compared with the case of reconnecting.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an ATM (Asynchronous Transfer Mode) network according to an embodiment of the present invention. In FIG. 1, an ATM network according to an embodiment of the present invention includes LEC (LAN Emulsion Client) terminals 11 to 14, a LECS (LAN Emulsion Configuration Server) terminal 21, a LES (LAN Emulsion Server) terminal 22, and a BUS (Broadcast). and Unknown Server) terminal 23 and ATM switches 31-33.
[0019]
The LEC terminals 11 to 14 are client terminals on which LEC is implemented, the LECS terminal 21 is an LE (LAN emulation) server terminal on which LECS is implemented, the LES terminal 22 is an LE server terminal on which LES is implemented, The BUS terminal 23 is an LE server terminal in which BUS is implemented. Here, LEC, LECS, LES, and BUS are as described in the above-described conventional technology.
[0020]
The ATM switch 31 is connected to the LECS terminal 21, the LES terminal 22, and the BUS terminal 23, respectively. The LEC terminals 11, 12, and 14 are connected to the ATM switch 32, and the LEC terminal 13 is connected to the ATM switch 33. Here, it is assumed that the LEC terminal 14 is hanging under the proxy of the LEC terminal 11.
[0021]
It is assumed that the ATM switches 31 to 33 are connected to each other, and all the LEC terminals 11 to 14 and the LECS terminal 21 support the expansion of the JOIN message described below.
[0022]
The expansion of the JOIN message is based on the SVC and LE_ARP between the LEC terminals 11 to 14 when the SVC (Switched Virtual Connection) disconnection occurs in the JOIN (participation) request for the LEC terminals 11 to 14 to join the network. A TLV (Type / Length / Value) indicating a time (hereinafter referred to as KEEP TIMER) for holding [MAC (Media Access Control) address and ATM address correspondence information] is added and transmitted, and the LES terminal 22 This is done by storing the time in the TLV and returning a JOIN response when it corresponds to KEEP TIMER.
[0023]
Here, the TLV is composed of a 4-byte Type part, a 1-byte Length part, and a Value part, and the value of the Length part represents the length of the Value part. In this case, the value of a certain parameter is specified by putting the parameter type in the Type portion and the value in the Value portion.
[0024]
In the present embodiment, in the inter-LEC communication in the LAN emulation network environment, the SVC between the LEC terminals 11 to 14 is held only during the time of KEEP TIMR, so that the communication impossible state due to the instantaneous SVC interruption with the LES terminal 22 is maintained. It is avoiding.
[0025]
FIG. 2 is a flowchart illustrating the operation of an ATM network according to an embodiment of the present invention. The operation of the ATM network according to one embodiment of the present invention will be described with reference to FIGS.
[0026]
The LEC terminals 11, 12, and 13 connect to the LECS terminal 21 using well-known well-known addresses in the network and acquire configuration information.
[0027]
Each of the LEC terminals 11 to 14 knows the ATM address of the LES terminal 22 from the acquired configuration information, and opens an SVC in the LES terminal 22. Since each of the LEC terminals 11 to 14 corresponds to the above KEEP TIMER, a JOIN request to which the KEEPTIMER TLV is added is transmitted to the LES terminal 22 (step S1 in FIG. 2).
[0028]
When receiving the JOIN request with the KEEP TIMER, the LES terminal 22 adds a TLV in which the KEEP TIMER holding time value T is set, and returns a JOIN response with success. Conversely, if the LES terminal 22 does not support KEEP TIMER, it returns a JOIN response as failure (step S2 in FIG. 2).
[0029]
When the JOIN response is successful, each of the LEC terminals 11 to 14 records the KEEP TIMER value T set in the TEEP of the KEEP TIMER, and thereafter connects to the BUS terminal 23 as usual and becomes communicable (FIG. 2). Step S3).
[0030]
When the JOIN response fails, each of the LEC terminals 11 to 14 transmits a normal JOIN request without a KEEP TIMER TLV (step S4 in FIG. 2), and thereafter, normal operation is performed.
[0031]
The preparation is completed by the processing so far. From here, the operation when the SVC between the LEC terminal 11 and the LES terminal 22 is disconnected while the LEC terminal 11 and the LEC terminal 13 are communicating will be described.
[0032]
The LEC terminal 11 that does not support KEEP TIMER deletes all information such as SVC and LE_ARP, and performs reconnection processing to the LECS terminal 21. The LES terminal 22 deletes the LECID assigned to the LEC terminal 11, its MAC address information, and ATM address information (steps S5 and S7 in FIG. 2).
[0033]
The LEC terminal 11 corresponding to the KEEP TIMER holds the SVC or LE_ARP cache established with the LEC terminal 13 for the time T, and continues communication with the LEC terminal 13. Further, the LES terminal 22 holds the LECID (LEC identification information) assigned to the LEC terminal 11 and its ATM address information during the time T (steps S5 and S6 in FIG. 2).
[0034]
The LEC terminal 11 attempts to establish an SVC with the LES terminal 22 during time T (step S8 in FIG. 2). If the SVC cannot be established within the time T, the LEC terminal 11 deletes all information such as SVC and LE_ARP, and performs reconnection processing to the LECS terminal 21. The LES terminal 22 deletes the LECID assigned to the LEC terminal 11, its MAC address information, and ATM address information (step S10 in FIG. 2).
[0035]
When the SVC can be established within the time T, the LEC terminal 11 sets the same LECID assigned by the previous JOIN response and transmits a JOIN request to the LES terminal 22. When LECID is set in the JOIN request, the LES terminal 22 performs matching between the held LECID and the ATM address (step S9 in FIG. 2).
[0036]
The LES terminal 22 responds with a failure if the designated LECID has not been allocated by matching the held LECID and the ATM address (step S11 in FIG. 2). In this case, the LEC terminal 11 deletes all information such as SVC and LE_ARP, and performs reconnection processing to the LECS terminal 21. The LES terminal 22 deletes the LECID assigned to the LEC terminal 11, its MAC address information, and ATM address information (step S14 in FIG. 2).
[0037]
In addition, when the LES terminal 22 has already been assigned to the LEC terminal having a different ATM address, another LECID that can be assigned at that time is set, and a response is made with success (step S11 in FIG. 2). In this case, the LEC terminal 11 deletes all information such as SVC and LE_ARP, and performs processing after the REGIST request to the LES terminal 22 as usual (step S13 in FIG. 2).
[0038]
Further, when the correspondence between the designated LECID and the ATM address is taken, the LES terminal 22 returns a success response with the LECID (step S11 in FIG. 2). In this case, since the matching between LECID “0001” and ATM address “39392f... 11” can be obtained, the LES terminal 22 returns a successful JOIN response to the LES terminal 11 without changing the LECID.
[0039]
Since the LEC terminal 11 returns the successful JOIN response without changing the LECID designated by itself, “0001”, the information so far is retained and the service is continued (step S12 in FIG. 2). Here, when the SVC with the BUS terminal 23 is disconnected, the BUS terminal 23 is also reconnected.
[0040]
Further, when the JOIN response is successful without changing the LECID, the LEC terminal 11 registers with a REGISTER request. Since the LE_ARP information of the proxy and the like (here, the MAC address is “00004C000044”) is also held by the LES terminal 22, it is not necessary to register again.
[0041]
In this way, in this embodiment, the SVC can be held between the LEC terminals 11 to 14 by extending the JOIN message. Therefore, even if the SVC with the LES terminal 22 is momentarily interrupted, the SVC between the LEC terminals 11 to 14 can be maintained. Communication is possible.
[0042]
Also, in this embodiment, if reconnection with the LES terminal 22 can be made within the KEEP TIMER time, the REGISTER request for registering the LE_ARP of the proxy and the LE_ARP resolution of the BUS terminal 23 are unnecessary, and the processing is simplified. The
[0043]
【The invention's effect】
As described above, the present invention is an ATM network that performs LAN emulation using an LEC that performs registration and acquisition of an ATM address and a MAC address, and an LES that performs address resolution between the MAC address and the ATM address. In, the SVC established between at least LEC using the message exchanged and extended between LEC and LES is retained when the SVC disconnection between LES and LEC occurs, and the retained SVC is used. Thus, by enabling communication between LECs to be continued when the SVC disconnection occurs, there is an effect that communication between LECs can be performed even if the SVC with LES is momentarily interrupted.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an ATM network according to an embodiment of the present invention.
FIG. 2 is a flowchart illustrating the operation of an ATM network according to an embodiment of the present invention.
[Explanation of symbols]
11-14 LEC terminal 21 LECS terminal 22 LES terminal 23 BUS terminal 31-33 ATM switch

Claims (8)

Registration and acquisition of ATM (Asynchronous Transfer Mode) address and MAC (Media Access Control) address, LEC (LAN emulation client) that executes registration and acquisition, and LES (LAN emulation) that performs address resolution between the MAC address and the ATM address An ATM network that executes LAN (Local Area Network) emulation using a server,
SVC (Switched Virtual Connection) established at least between the LEC using an extended message exchanged between the LEC and the LES is also retained when an SVC disconnection between the LES and the LEC occurs. Means to
An ATM network characterized in that communication between the LECs can be continued even when the SVC disconnection occurs using the held SVC. 2. The ATM network according to claim 1, further comprising means for directly connecting from the LEC to the LES when reconnecting from the LEC to the LES after the SVC disconnection. 3. The ATM network according to claim 1, wherein the SVC can be held between the previous LECs by extending a JOIN message for the LEC to join the network. When the SVC disconnection occurs with the LES, the extension of the JOIN message is performed when the time for holding the SVC between the LECs is added to the JOIN request and transmitted to the LES, and the LES side supports the time. 4. The ATM network according to claim 3, wherein a JOIN response to which the time is added is returned to the LEC. Registration and acquisition of ATM (Asynchronous Transfer Mode) address and MAC (Media Access Control) address, LEC (LAN emulation client) that executes registration and acquisition, and LES (LAN emulation) that performs address resolution between the MAC address and the ATM address A network management method for an ATM network that executes LAN (Local Area Network) emulation using a server,
SVC (Switched Virtual Connection) established at least between the LEC using an extended message exchanged between the LEC and the LES is also retained when an SVC disconnection between the LES and the LEC occurs. A network management method, comprising: a step of maintaining the communication between the LECs even when the SVC disconnection occurs using the held SVC. 6. The network management method according to claim 5, further comprising the step of directly connecting to the LES when reconnecting from the LEC to the LES after the SVC disconnection. The network management method according to claim 5 or 6 , wherein the SVC can be held between the previous LECs by extending a JOIN message for the LEC to join the network. When the SVC disconnection occurs with the LES, the extension of the JOIN message is performed when the time for holding the SVC between the LECs is added to the JOIN request and transmitted to the LES, and the LES side supports the time. 8. The network management method according to claim 7, wherein a JOIN response to which the time is added is returned to the LEC.

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