Is loopback interface on router mandatory for DLSw ?

[luc_m]

Hi,

for simplify the routing on my network, i need to know if using loopback address is really mandatory for DLSw ?

In my configuration the routers are on stick (only one interface, ethernet) and the loopback address complexify my routing.

Thanks for your help,

Luc Mignerey

[dixho · Accepted solution]

No. it is not mandatory.

Generail speaking, it is recommended to use loopback address as DLSw local peer ID. The reason is that all DLSw peer connections will be lost when you use the IP address of a physical interface as DLSw local peer ID and the physical interface is down.

In your case, it does not really matter if you use the loopback or ethernet interface. As there is only two interfaces (I assume. A WAN interface and an ethernet interface), you enable transparent bridging on the ethernet interface. If the ethernet interface goes down, the router is unable to accept SNA/NETBIOS frames anyway.

[luc_m]

In my case, the router have only one interface (Ethernet) and no other interface (no wan). Routing to central site is made by an another router (non cisco). the first router is only here for dlsw.

I hope this configuration is ok ?

Thank you for your help !

[ozkarakok · Accepted solution]

As Dixon said, it is not mandatory to use the loopback ip address in your dlsw+ configuration.If you only have one interface , it means that you will going to use that interface for ip and to bridge your SNA traffic. Depending on your ip and SNA traffic rate , it will not be a good idea. But your configuration will be correct for dlsw.

[luc_m]

Thank for your help and also for the remark about traffic rate. It's not a concern in my configuration.

Luc Mignerey