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Configuring DLSw Ethernet Redundancy (Optional)

When more than one DLSw router is connected on the same LAN segment, there are DLSw design limitations for providing redundancy and load sharing. When DLSw Ethernet redundancy is configured on the network, it enables DLSw to support parallel paths between two points in an Ethernet environment, ensuring a recovery point in the case of router failure.

When DLSw Ethernet redundancy is configured on a LAN segment, one router (DLSw peer), is selected to act as the master router, and other routers become backup routers, depending on the configured priority, in a group of DLSw peers. Only the master router establishes circuits and connections on the LAN and maintains a database of known DLSw peers on the network. By maintaining a circuit database, the master router prevents duplicate circuits from being created for the same SNA session. In addition, only the master router accepts incoming LLC connections while the backup routers simply drop the connections.

When the master router fails, all incoming connections cease, and the backup router with a higher priority than other backup routers becomes the master router and begins handling all connections.

Figure 11 shows a typical use of Ethernet LAN redundancy in a DLSw network.

Figure 11: DLSw Ethernet Redundancy Network Topology

Image g017203.gif

In Figure 11, the local hosts share the same destination MAC address of 00:22:22:22:22:22 and send DLSw traffic to the remote host with a MAC address of 00:30:48:84:99:45. Router 1 and Router 2 are configured as a DLSw redundancy group and map the local destination MAC address to the remote MAC address. Router 1 is the designated master and if Router 1 becomes unavailable, Router 2 takes over as the master router.

The priority cost feature is used to determine the effective priority by subtracting the priority cost from the configured priority when a tracked event occurs, such as the unavailability of a remote DLSw peer.

To configure DLSw Ethernet redundancy on the DLSw peer Services Router, you do the following:

To configure DLSw Ethernet redundancy on a DLSw peer:

  1. Navigate to the top of the configuration hierarchy in either the J-Web or CLI configuration editor.
  2. Perform the configuration tasks described in Table 57.
  3. If you are finished configuring the router, commit the configuration.
  4. To verify the DLSw configuration, see Verifying DLSw Configuration.

Table 57: Configuring DLSw Ethernet Redundancy on a DLSw Peer Router

Task

J-Web Configuration Editor

CLI Configuration Editor

Navigate to the Interfaces level in the configuration hierarchy.

In the configuration editor hierarchy, select Interfaces>Edit.

From the top of the configuration hierarchy, enter

edit interfaces fe-1/0/0 unit 0 family llc2

Edit the LLC type 2 properties on a Fast Ethernet interface—for example, fe-1/0/0.
  1. Next to the interface fe-1/0/0, click Edit.
  2. Next to Unit, click Edit.
  3. Under Family, select Llc2, and then click Configure.
 

Create a redundancy group—for example 100.
  1. Next to Redundancy group, click Add new entry.
  2. In the Group Id box, type 100.

Enter set redundancy-group 100

Map a local peer MAC address to a remote peer MAC address. For instance, the local peer MAC address is 00:22:22:22:22:22 and the remote peer MAC address is 00:30:48:84:99:45.
  1. Next to Map, select Yes.
  2. Click Configure.
  3. Next to Local mac, click Add new entry.
  4. In the Local address box, type 00:22:22:22:22:22.
  5. In the Remote mac box, type 00:30:48:84:99:45.
  6. Click OK.

Enter

set redundancy-group 100 map local-mac 00:22:22:22:22:22 remote-mac 00:30:48:84:99:45

Configure a priority value between 0 and 255 for the group. The default value is 100.

The priority value determines which DLSw peer becomes the master router during master router selection.

In the Priority box, type 250.

Enter

set redundancy-group 100 priority 250

Configure tracking options for the remote peer and destination.

The track parameter is used to track events such as the unavailability of a remote DSLw peer.

Priority cost is subtracted from the priority value when remote peer connectivity is lost, and has a value between 1 and 254.
  1. Next to Track, click Configure.
  2. Next to DLSw, click Configure.
  3. Next to Destination, click Add new entry.
  4. In the Mac address box, type 00:30:48:84:99:45.
  5. In the Priority cost box, type 50.
  6. Click OK.
  7. Next to Peer, click Add new entry.
  8. In the Ip address box, type the IP address of the remote peer—for example, 10.10.10.1.
  9. In the Priority cost box, type 30.
  10. Click OK until you return to the Redundancy group page.

Enter

set redundancy-group 100 track dlsw destination 00:22:22:22:22:22 priority-cost 30

Enter

set redundancy-group 00:30:48:84:99:45 track dlsw peer 10.10.10.1 priority-cost 30

Configure advertisement of DLSw peers on the network. Advertise interval has a value between 1 and 255 seconds. The default value is 1.

The preempt parameter determines if a higher-priority backup router takes over for a lower-priority master router.
  1. From the Advertisement type list, select Advertise interval.
  2. In the Advertise interval box, type 1.
  3. From the Preemption type list, select no preempt.
  4. Click OK.

Enter

set redundancy-group 100 advertise-interval 1

Enter

set redundancy-group group 100 no-preempt

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