KR100553798B1 - A method for checking physical link topology using loopback in ATM networks - Google Patents

Abstract

The present invention relates to a method for identifying a physical link topology using a loopback in an asynchronous transmission mode (ATM) high speed information communication network. The present invention provides a method for identifying ports at both ends of a physical link configured in a database of a network management system, and a loopback location identifier (LLID: Loopback) for changing or deleted information of the link identified above. How to use the NNI port's circular shift scheme and parallel ATM layer end-to-end loopback without using Location ID, and loopback location identifier (LLID) for the changed or deleted information of the link identified above. It is configured to verify by ATM layer segment loopback, and the information of the physical link can be confirmed by the VP connection currentization function, the VP connection establishment function, and the ATM layer loopback function, thereby automating the topology checking structure. .

Description

A method for checking physical link topology using loopback in ATM networks}

1 is a diagram showing the structure of a typical ATM high speed information network;

2 is an overall flow chart of the present invention.

3 is a flowchart of a method for identifying a physical link configured in a network management system (NMS) database (DB: Database).

4 is a flow chart of a method of verifying information of a changed or deleted physical link without using a loopback location identifier (LLID).

5 is a flow chart of a method for verifying information of a changed or deleted physical link using a loopback location identifier (LLID).

6 is a diagram illustrating port status and connection for each node.

The present invention relates to a physical link topology checking method using loopback in an asynchronous transmission mode high-speed information communication network. More specifically, in the network configuration resource allocation scheme in an ATM high-speed information communication network, ITU-T Recommendation M.3400 defines The present invention relates to a physical link topology verification method using loopback in an asynchronous transmission mode ultrahigh speed information communication network having improved configuration management among five functions of a telecommunications management network (TMN) structure.

The network consists of subnetworks, nodes, links, and access ports defined according to the TMN object class defined by ITU-T M.3100 and G.805. Connection services are provided over one or more nodes and links through appropriate routing between end-to-end subscribers or between physical ports.

In resource configuration management, links have a great influence on connection management that performs the actual routing, and are essential to efficiently support connection services and to manage network support.

1 is a block diagram showing the structure of a typical ATM high speed information communication network.

In the drawings, reference numeral 100 denotes a database, 200 denotes a network management system (NMS), 300 and 310 denote first and second element management systems (EMS), and 320 denotes an agent. ), 400 and 500 represent ATM networks, respectively.

Each ATM switch is managed by an element management system, and in the case of a core switch, one agent is directly managed by each core switch. These element management systems and agents are managed by the network management system, and all information is stored in the database.

In FIG. 1, the first element management system 300 manages three ATM switches 410, 420, and 430 included in the ATM network 400, and the second element management system 310 stores the ATM network 500. The two ATM exchangers 510 and 520 are included in the management, and the agent 320 manages the core switch 600.

In this case, each element management system and agent can manage only the corresponding ATM switch or core switch, but not another element management system or agent.

Specifically, the first element management system 300 may not manage the ATM switches 510 and 520 and the core switch 600, and likewise, the second element management system 310 may include the ATM switches 410, 420 and 430 and the core switch ( 600 may not be managed, and the agent 320 may not manage the ATM exchangers 410, 420, 430, 510, 520, and 600.

And, as shown in the figure, a link between ATM switches belonging to the same element management system (La, Lc), a link between ATM switches belonging to different element management systems (Lb), between the ATM switch and the core switch. There is a link Ld.

Therefore, the first element management system 300 can know the information about the link (La), but the information about the link (Lb) is not known because the other side of the link does not belong to the ATM network 400, and likewise the second The element management system 310 may know the information about the link Lc, but not the information about the links Lb and Ld, and the agent 320 may not know the information about the link Ld.

Therefore, when the network management system 200 requests each element management system 300 or 310 or the agent 320 about the link, each element management system and the agent provide information about the complete link. I can't tell

For the above reasons, the confirmation of the physical link configuration has only relied on loopback at the manual or physical layer. In particular, the physical layer loopback is not possible between these exchanges, and in fact could not be automated. Links Lb and Ld in the figure correspond to the example.

An object of the present invention is to manage information on a physical link that has been changed or deleted between ATM switches at the network management system level.

Another object of the present invention is to automatically use the virtual path (VP) connection realization function (to check the VPI being used on the port), the VP connection establishment function (to set the VPI on the port) and ATM layer loopback function. This is to check the information of the changed or deleted physical link and to reorganize the contents of the database.

In order to achieve the above object, a physical link topology verification method using loopback in an asynchronous transmission mode ultrahigh speed information communication network according to the present invention includes a connection between a VP connection setting and a port of both ends of each physical link configured in a database of a network management system. Performing an ATM layer end-to-end loopback to check the physical link to set verify complete if successful and require reconfirm if not successful, and for the physical link set to require reconfirmation in the physical link. If you want to check using the loopback position identifier (LLID), do not use the loopback position identifier (LLID) for the physical link set to require re-confirmation in the step of verifying the physical link with segment loopback and the step of checking the physical link. End-to-end And a step of identifying the physical link to peubaek.

The checking of the physical link may include checking a VPI in use at both ends of the link by selecting the link set in the step of setting all the physical links to the link unchecked state and the setting of the link unchecked state. In the step of checking the VPI, it is determined that a failure of the ports at both ends, if the failure is set to the link unrecognized state, if not, creating a new VP connection, the end of the connection created in the step of creating a new VP connection Performing a two-end loopback, setting the link check completion if the loopback is successful in the loopback step, setting the link re-verification required if not successful, and deleting the connected VPI in the step of creating the new VP connection. It is equipped with a step.

The identifying of the physical link by the segment loopback may include selecting a link set to require link re-confirmation to set the link deletion confirmation and searching for NNI ports of two nodes of the link selected in the link deletion confirmation. Setting the one with less NNI ports as the first node and the other as the second node, and setting all NNI ports of the first node to the port unidentified state, and searching for the VPI being used by the NNI ports of the second node. Setting a VPI that is not used in any of the ports to all ports of the first node and the second node, selecting a port that is set to the unidentified port state, and performing segment loopback, if the loopback does not succeed Setting port verification complete, and if successful, setting a successful pair port to link verification complete and setting the VPI to 1 And deleting the set VPI in the setting in all ports of the node and the second node.

In addition, the checking of the physical link by the end-to-end loopback may include selecting a link set to require link re-confirmation and setting the link deletion confirmation to one node of the link selected in the link deletion confirmation. To arbitrarily set the third node, arrange all NNI ports, set the opposite node as the fourth node, and arrange all NNI ports, and map the pairs 1: 1 by the port arrangement of the third node and the fourth node. Configure a connection between the paired ports, perform end-to-end loopback in parallel between the paired ports, and if the loopback does not succeed, set all connections established in the step of establishing a VP connection. Deleting and circularly shifting the ports of the third node one by one to check if they are the same as the above sorting, If the loopback succeeds in the step, configure the successful pair port as a link, set the link confirmation complete, delete the link set to the link deletion confirmation, and delete the VP connection established in the step of establishing the VP connection. do.

Hereinafter, a method of confirming a physical link topology using loopback in an asynchronous transmission mode ultra high speed information communication network according to the present invention will be described in detail with reference to FIGS. 2 to 6.

In the asynchronous transmission mode ultra-high speed information communication network according to the present invention, a method for confirming a physical link topology using loopback includes a method for identifying ports at both ends of a physical link configured in a database of a network management system, and changing or deleting the link identified above. And a method for confirming the changed or deleted information of the link identified above using the loopback location identifier (LLID).

The method of verifying the changed or deleted information of the physical link without using the loopback location identifier (LLID) includes a circular shift technique of the NNI port and a parallel end-to-end loopback, and the loopback location identifier (LLID). The method of checking using) consists of segment loopback.

The Loopback Location Identifier (LLID) is an option for OAM (Operations And Maintenance) cells that move when looping back and forth between links. This option is applicable only to segment loopback. The loopback OAM cell is for verifying connectivity. In the case of end-to-end loopback, the loopback starts from the start of the connection and returns when the end point is reached. If you shed from the point, you come back from the opposite end. The success of the loopback is determined by the return of the loopback OAM cell within 5 seconds by ITU-T I.610.

The client may request the network management system to perform the method according to the present invention. The client may be a Service Management System (SMS), an operator terminal, or the network management system itself, which is on top of the network management system, and the network management system may provide a method according to the present invention at the request of such a client. As a result of execution by the server, information about the link is reconstructed into the database of the network management system.

The execution of the method according to the present invention with respect to the request of the client may be performed regularly, according to the needs of the operator, or may be performed when the connection operation of the service network fails. Typically, if the network is stable, it can be done once a day at night.

FIG. 2 is a flowchart illustrating a method of confirming information about a physical link configured in the database 100 of the network management system 200, and loopback position of changed or deleted information of the link identified above. A method for verifying without using an identifier (LLID), and a method for verifying changed or deleted information of the link identified above using the loopback location identifier (LLID).

First, the information configured in the database of the network management system is read first, and both ports of the corresponding physical link are checked by loopback (S100). If loopback is successful in the step is set to for example LS _confirmed to be a complete check on the link information, for example to double-check the link loopback If this is unsuccessful is set as LS _twist. This operation is performed for all links registered in the database.

Next, the link in the database is determined whether or not that the LS and _twist set (S110), to end if there is no _twist LS, reaffirm the link If the LS _twist.

Subsequently, the link set to LS _twist is reconfirmed. At this time, it is checked whether the loopback location identifier (LLID) is used or not (S120). Here, if the loopback location identifier (LLID) is not used, the link is re-checked by end-to-end loopback (S130), and when the loopback location identifier (LLID) is used, the link is re-checked using the segment loopback (S140). ).

The step S100 of checking all the links of the database shown in FIG. 2 by loopback will be described in more detail with reference to FIG. 3.

Figure 3 sets the status of all links to LS _reset (unconfirmed state) and checks each, and if it matches the actual configuration, it is set to LS _confirmed (confirmation completed), if not matched to LS _twist (need to confirm). In case of fault state, both connection creation and loopback are impossible, so set to LS _alarm (uncheckable state) and check again after clearing fault state.

Specifically, first, all links of the database of the network management system are set to LS _reset (S200). After selecting one of the LS _reset links (S210), all of the VPIs (Virtual Path Identifiers) used in both ports of the link are checked (S220).

In the next step, it is confirmed that the failure state of the ports at both ends (S230). If at least one of the disabled set the link to LS _alarm (S240).

If it is not a failure, a VP connection is created at both ends of the link as an endpoint (S250). At this time, the VPI identified in the connection currentization VPI check step (S220) is avoided and generated. The loopback is performed on the connection thus generated (S260), and it is determined whether or not it is successful (S270). If this fails, the link is set to LS _twist (S290), and the VP connection generated above is deleted (S300).

On the other hand, if the loopback is successful, the corresponding link is set to LS _confirmed (S280), and the VP connection generated above is deleted (S300).

Subsequently, it is checked whether the link set to LS _reset remains (S310), and if so, the link that is LS _reset is selected (S210) and the process is repeated.

If the link is checked as above, the link set to LS _twist must be rechecked.

There are two methods of checking the link with the end-to-end loopback of FIG. 2 (S130) and the method of checking the link with the segment loopback (S140). The difference between the two methods lies in the use of the loopback location identifier (LLID).

If the loopback location identifier (LLID) is not used, as shown in FIG. 4, the link set to LS _{twist is identified} by a circular shift scheme of the NNI port and a parallel end-to-end loopback.

The method will be described in more detail with reference to the drawings.

First, the link set to the LS _twist is selected (S400). The selected link is set to LS _disappeared (S410).

One node of the link is arbitrarily determined as aEnd, and all NNI ports are arranged (S420). Subsequently, the opposite node is set as zEnd and all NNI ports are aligned (S430). The pairs of the aEnd and zEnd ports are mapped in a 1: 1 order to configure a pair port and establish a VP connection between each pair port (S440).

And end-to-end loopback is performed in parallel between all pair ports (S450), it is determined whether the loopback is successful (S460), and in case of failure, all set connections are deleted (S470), and the above ( S420) The aligned aEnd ports are circularly shifted one by one (S480), and the result of the shift is checked to be the same as the first alignment (S420) (S490). If the aligned port is the same as the initial alignment (S420), it means that the loopback check has been completed for all NNI port combinations between the two nodes. If the result of the check in step S490 is the same, the LS _twist link is moved to the next step, and if it is not the same, the process starts again from step S440 according to the alignment of the new port.

On the other hand, if the loopback succeeds, configures the successful pair port as a link, sets LS _confirmed , and deletes the LS _disappeared link from the database (S500). Thereafter, all VP connections (S440) established between the paired ports are deleted (S510). Check whether the LS _twist- in link remains (S520). If the link remains, the process proceeds to step S400 of selecting the LS _twist- in link (S400), and ends if the LS _twist link does not remain.

The maximum time (T _MAX ) for obtaining a link between two nodes, which is the basis for determining whether the loopback is successful, is as follows.

T _MAX = max (N _aEnd , N _zEnd ) * (5 + T _setup + T _release ).

Where N _aEnd is the number of NNI ports on the aEnd node, N _zEnd is the number of NNI ports on the zEnd node, T _setup is the connection setup time, T _release is the connection release time, and 5 is the time when the OAM cell returns, The unit is seconds.

Next, a case of using a loopback location identifier (LLID) will be described in detail with reference to FIG. 5.

First, the link set to LS _twist in FIG. 3 is selected (S600). The link is set to LS _disappeared (S610).

Here, the NNI ports of the two nodes of the link are searched (S620), and the NNI port having the fewest NNI ports is set as an aEnd node, the other end as a zEnd node, and all NNI ports of aEnd are set to PS _reset (unchecked state). S630). Next, after searching for the VPI used by the NNI ports of the zEnd, the VPI that is not used in any of the ports is set to all ports of aEnd and zEnd (S640).

Subsequently, one of the ports of aEnd set to PS _reset is arbitrarily selected (S650). If there is no port set to PS _reset , it is checked whether the LS _twist link remains (S710). If there is a port set to PS _reset , segment loopback is performed in which the ports of the zEnd and the loopback location identifier (LLID) are set to a universal address (all 0s) (S660). In operation S670, it is determined whether the segment loopback is successful.

At this time, if the segment loopback does not succeed, the port is set to PS _confirmed (S680). While performing the above process, all ports that are set to PS _reset among the ports of aEnd are searched.

If the segment loopback succeeds, search the loopback location identifier (LLID) field of the returned OAM cell to find the pair port, configure it as a link, set it to LS _confirmed , and then delete the LS _disappeared link from the database. S690).

Finally, in the setting of the VPI (S640), all the VPIs set in step S700 are erased (S700), and the LS _twist link remains (S710).

The maximum time T _MAX for obtaining a link between two nodes, which is the basis for determining whether the loopback is successful, is as follows.

T _MAX = min (N _aEnd , N _zEnd ) + 5 + T _get + T _setup + T _release ).

Where N _aEnd is the number of NNI ports on the aEnd node, N _zEnd is the number of NNI ports on the zEnd node, is VPI discovery time, T _setup is the connection setup time, T _release is the connection release time, and 5 is the time when the OAM cell returns. All units of time are seconds.

Finally, referring to FIG. 6, when the link between the ATM node AA and another ATM node bb is changed from port Bb to port Ab, an example of verifying the link with end-to-end loopback and an example of verifying the link with segment loopback are described. Explain each.

Node AA is composed of A, B, and C ports, and node bb is composed of a, b ports.

First, when the link is confirmed by the end-to-end loopback shown in FIG. 4, the node AA is arbitrarily selected as aEnd, and the port order of the aEnd is arranged from A to B to C (S420). The node bb is defined as zEnd and the port order of zEnd is sorted from a → b (S430). At this time, the pair ports are Aa and Bb, and C cannot form a pair. If a connection is made between Aa and Bb (S440) and loopback is performed (S450), all of them fail. Then, after deleting the new connection (S470), a circular shift of the port of aEnd (S480). At this time, port alignment of aEnd becomes as C → A → B, pair port becomes Ca, Ab, and port B does not form a pair. At this time, if loopback is performed between pair ports (S450) and Ab succeeds (S460), it is set to LS _confirmed (S500), and then deletes a new connection (S510).

On the other hand, when the link is confirmed by the segment loopback shown in FIG. 5, node bb having a small number of ports is set to aEnd, node AA is set to zEnd, and both ports a and b of node bb are set to PS _reset (S630). ). All unused VPIs are selected from the A, B, and C ports of the node AA and set to the A, B, C, and a, b ports (S640).

If the randomly selected PS _reset port is a (S650), all of the loopbacks performed at the port a toward the node AA (S660) will fail (S670). Thus, after setting port a to PS _confirmed (S680) and searching for the PS _reset port, port b matches the condition (S650).

The loopback performed on port b succeeds (S670), and the loopback location identifier (LLID) field of the returned OAM cell is set to A. Using this, Ab is set to LS _confirmed (S690) and the VPI set above is deleted (S700).

As described above, the present invention compares the information of the physical link stored in the database of the network management system with the actual situation in the ATM high-speed information communication network to automatically check the configuration of the physical link by checking the link change or deletion. This can reduce manual loopback at the physical or physical layers.

In addition, the present invention can automatically determine the topology of the link, establish a database of a reliable network management system for the physical network, and enables reliable routing or fault propagation.

Claims (4)

The ports on each end of each physical link in the network management system's database are configured to perform VP connection setup and ATM layer end-to-end loopback to set the check to successful if successful and the need to reconfirm if not successful. Checking the link; Checking the physical link by segment loopback when checking the physical link using a loopback location identifier (LLID) for the physical link set to need to be re-confirmed in the checking of the physical link; And And checking the physical link with end-to-end loopback when checking the physical link without using a loopback location identifier (LLID) for the physical link set to need to be reconfirmed. Examining the physical link, Setting all physical links to a link unchecked state; Selecting a link established in the setting of the link unconfirmed state to identify a VPI in use at both ends of the link; Confirming that the ports are both out of the ports at the step of verifying the VPI, setting a link non-identification state if the failure occurs and creating a new VP connection if the failure does not occur; Performing end-to-end loopback on the connection created in the step of creating a new VP connection; Setting a link check completion if the loop back is successful in the performing the loop back and setting a link re-check required if the loop back is not successful; And And deleting the connected VPI in the step of creating the new VP connection. delete The method of claim 1, Identifying the physical link with the segment loopback, Selecting a link set to require link re-confirmation and setting the link deletion confirmation; In the step of setting the link deletion confirmation, the NNI ports of two nodes of the selected link are searched, the one with less NNI ports is set as the first node and the other node as the second node, and all NNI ports of the first node are in the port unchecked state. Setting to; Retrieving the VPI being used by the NNI ports of the second node and setting VPIs not used in any ports to all ports of the first node and the second node; Selecting a port set to the port unchecked state and performing segment loopback; Setting a port check completion if the loopback does not succeed, and setting a successful pair port to link check completion if the loopback succeeds; And And deleting the set VPI in the step of setting the VPI to all ports of the first node and the second node. The method of claim 1, Identifying a physical link with the end-to-end loopback; Selecting a link set to require link re-confirmation and setting the link deletion confirmation; Setting one link of the selected link as a third node, arranging all NNI ports, arranging the opposite node as a fourth node, and arranging all NNI ports in the setting of the link deletion confirmation; Configuring a pair port by mapping 1: 1 to the port arrangements of the third node and the fourth node, and establishing a VP connection between each pair port; Performing end-to-end loopback in parallel between the pair ports; If the loopback does not succeed, deleting all the connections established in the establishing the VP connection and circularly shifting the ports of the third node by one space to check whether the alignment is the same as the above alignment; If the loopback succeeds in performing the loopback, configuring a successful pair port as a link, setting the link confirmation completion, and then deleting the link set as the link deletion confirmation; And And deleting the VP connection established in the step of establishing the VP connection.

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