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Community Member

dlsw token ring transparent bridging

My customer has a token ring network with no ring number so I think this token ring with transparent bridging. I need to connect SNA station on this network to a remote Ethernet network via two routers using Dlsw.

When I configure the token ring adapter with source-bridge 1 1 2000 ( for

exemple) sna stations cannot be connected to remote host.

If I isolate my token ring router, a sna station on a hub then SNA session is ok.

So is it possible to customize a token ring adapter to run transparent bridging.?

Community Member

Re: dlsw token ring transparent bridging

Is the router connected to a hub/mau or switch? A typicaly SNA workstation will send a "local" explorer (does not contact a RIF) and a source routed explorer. If your router is configured for source routing on the physical token ring then it will bridge the source routed explorer but ignore the local explorer. If you are transparent bridging on the router the source routed explorer is ignored and the local explorer is bridged. If there is a switch between the client and the router the switch may be configured to only pass source routed or transparent. If this is the case, then you need to know how the switch is configured before you can configure the router.

Assuming you do not have a switch you can configured the router to transparent bridge the local explorers into dlsw by first creating a bridge group, assigning the interface to it, then assigning dlsw to it. The following is a simple example:

dlsw local-peer pee-id

dlsw remote-peer 0 tcp

dlsw bridge-group 1


interface token ring 0/1

no ip address

bridge-group 1


bridge 1 protocol ieee.

Hope this helps


Community Member

Re: dlsw token ring transparent bridging

Thank you very much for the quick answer, dlsw now is OK.

The only strange think is that parameter bridge-group 1 on token ring does not

appears in show run config output...... IOS 12.2...... but Dlsw is OK.

Thanks for help. Patrick.

Community Member

Re: dlsw token ring transparent bridging

The bridge-group should show up in the config if it was configured. You can issue a "show span" and see if that token ring interface is forwarding within the bridge-group. If you see the token ring interface listed in the show span then it really is using transparent bridging. If it is not listed, then the traffic must be working via source route bridging.

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