Cisco IOS Cookbook, 2nd Edition

DLSw+ Redundancy and Fault Tolerance

Problem

You want to improve the fault tolerance of your DLSw network.

Solution

There are several things you can do to improve the reliability and fault tolerance of your network. Many of these solutions have the added benefit of improving performance. The first important thing to consider is having more than one DLSw peer router connected to the mainframe’s Token Ring. In this case, you will want to make sure that you balance the load between the two peers as much as possible:

dlsw-branch#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
dlsw-branch(config)#source-bridge ring-group 101
dlsw-branch(config)#dlsw local-peer peer-id 10.1.2.5
dlsw-branch(config)#dlsw timer explorer-wait-time 5
dlsw-branch(config)#dlsw load-balance circuit-count
dlsw-branch(config)#dlsw remote-peer 0 tcp 10.1.1.5 lsap-output-list 200
dlsw-branch(config)#dlsw remote-peer 0 tcp 10.1.1.9 lsap-output-list 200
dlsw-branch(config)#dlsw allroute-sna
dlsw-branch(config)#end
dlsw-branch#

Discussion

This example is extremely similar to the one shown in Recipe 15.2, so the interface parts of the configuration are left out for simplicity. The main difference is the presence of a second dlsw remote-peer command. This command points to the IP address of a second router that is on the same central Token Ring as the mainframe. So the same mainframe MAC address is visible on this branch router coming from both DLSw peers.

The command dlsw load-balance circuit-count ...