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Community Member

Bridge IRB and router administration - 1603 router


We need to make a couple of changes to our configuration and would appreciate any feedback on possible pitfalls.

The configuration is as follows:

2 x Cisco 1603 Routers on ethernet LANs linked via leased line.

Router 1 -

configured for Bridge IRB

Ethernet + Serial + BVI all in bridge-group 1

Ethernet - no IP address

BVI - 192.168.0.y

Admin only via console port or ISDN BRI0 incoming.

Router 2 -

Ethernet + Serial in bridge-group 1

Ethernet - 192.168.0.x

Admin via ethernet IP address

We need to achieve the following:

1. Change the IP addresses - that's OK but how is the BVI IP address actually used and what are the implications of changing it ?

2. Get admin via the local ethernet for router 1 if possible - will assigning an IP address interfere with the bridge operation.

Many thanks

Hall of Fame Super Silver

Re: Bridge IRB and router administration - 1603 router

Hello Philip,

for R1 you should be able to access it via telnet using the BVI ip address

verify that:

there are the commands

bridge 1 bridge ip

bridge 1 route ip

and a default route pointing to 192.168.0.x

only doubt :

192.168.0.x should be associated to BV1 on R2 too otherwise how could the two ip addresses have a direct communication ?

I think this is your issue

eth1 on R2 should be in a different subnet and all should be fine

Hope to help


Community Member

Re: Bridge IRB and router administration - 1603 router

Hi Guiseppe,

Thank you for the response.

R1 doesn't respond to telnet on the BVI IP.

It's missing the Bridge 1 bridge ip command.

Also I can't see any reference to a default route on either router.

In addition, we would like both ends to be on the same subnet ?

If we configure both routers with the same BVI IP, how could I telnet onto one via that IP ?

I'm wondering if this is just completely mi-configured but lucky it's working.

Would you consider glancing at the IOS commands if I post them ? I understand if you don't have time.

Thanks again

Hall of Fame Super Silver

Re: Bridge IRB and router administration - 1603 router

Hello Philip,

the two routers must share a common IP subnet.

R1:Bvi1 and R2:bvi1 need to be in the same subnet but to be different




if you want you can make also R2:eth1 part of same bridge-group 1 to support a flat network (using a single IP subnet)

to be able to telnet you need also to set a password under line vty

line vty 0 4


password thisisapass

when you can ping R1:BVI1 from R2 you should be fine.

the default route is needed to reach other subnets if there is only a subnet you don't need it.

If needed R1 can point to R2:Bvi1 and R2 to some other router to reach other IP subnets

Hope to help


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