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Problem with translational bridging of IP


I am currently migrating from TR to ethernet. I would like to retain the IP subnet currently in use for both sides of the network.


The new ethernet network consists of a couple of 3550-12G at the core acting as L3 switches, linked to a mixture of 2950-48 and 2950-24 switches. There are 2 VLANs 1 for managment the other for users (with the same subnet as TR) - 802.1Q trunking is enabled between the switches - this works ok

The legacy TR side consists of various segments linked using a couple of Madge Ringswitches

To link the two networks together I've used a 2612 router.

The IOS version on this unit is c2600-js-mz.122-5d.bin

Ip routing has been disabled on this unit with the following configured forbridging:

"no ip routing


bridge irb


source-bridge ring-group 769

source-bridge transparent 769 770 1 1


interface Ethernet0/0

ip address

no ip route-cache

no ip mroute-cache


bridge-group 1


interface TokenRing0/0

no ip address

no ip route-cache

no ip mroute-cache

ring-speed 16

multiring all

bridge-group 1

source-bridge 1027 1 769

source-bridge spanning



bridge 1 protocol ieee

bridge 1 bitswap-layer3-addresses

bridge 1 route ip"

On the ethernet side all of the cisco switches have learned the TR MAC addresses. If I check the RIF info on the 2612 I get the following:

"0000.3042.3264 N/A To0/0 2 - 06B0.4041.4030

0000.f6b8.1a7c N/A To0/0 2 - 06B0.2011.4030

0000.f6b8.1a7c N/A BG1 2 - 0A90.2011.4031.3011.3020

0000.f66f.04b4 N/A BG1 6 - 0A90.1031.4031.3011.3020

0000.f6b9.9afc N/A BG1 0 - 0A90.1031.4031.3011.3020"

If I attach a protocol analyser to the ethernet, I learn TR MAC addresses, I also see IP multicast and broadcast traffic from TR and also IPX broadcast traffic

The problem . . .

A device on ethernet in the correct VLAN with an IP address in the same subnet as the devices on TR is unable to ping the default gateway (cisco 2500) attached to TR or any other TR attached device fro that matter!

Hopefully someone can help me?




Re: Problem with translational bridging of IP

Better check your configuration, for troubleshooting go through this document,

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