how to configure router for bridging

[saviopereira]

hi , please help me in following senario

we have a private leased line and i want to configure the two routers for bridging, if i enable on bridging on serial int , the serial int shutsdown.if u can please tell me what are the commands to enable bridging

eg router 1 e0 207.132.222.105 255.255.255.224

s0 207.132.222.106 255.255.255.224

router2 e0 207.132.222.104 255.255.255.224

s0 207.132.222.103 255.255.255.224

[Kevin Dorrell]

If you want to do remote transparent bridging over a serial link, you don't need to configure any IP addresses at all. You can bridge the layer-2 directly. Here is a document that tells you how to do it, with some great configuration examples:

http://www.cisco.com/warp/public/701/37.html

There is even a bit about IRB, which is the technique to use if you want to route packets into and out of the bridged LAN.

Kevin Dorrell

Luxembourg

[saviopereira]

i have configured bridging on both the routers but still i am not able to ping from one network to the other network

e0 is up , s0 is also up on both routers

[Kevin Dorrell]

Could you post the configs of both your routers please?

Thanks

Kevin Dorrell

Luxembourg

[Kevin Dorrell]

Could you post the configs of both your routers please?

Thanks

Kevin Dorrell

Luxembourg

[saviopereira]

router 1

!

!

hostname xxx

!

boot-start-marker

boot-end-marker

!

no logging on

enable secret xxxxx

!

no aaa new-model

ip subnet-zero

!

!

!

!

ip cef

no scripting tcl init

no scripting tcl encdir

!

!

!

!

interface FastEthernet0

no ip address

speed auto

bridge-group 1

!

interface Serial0

description connected to Bahrain

bandwidth 128

no fair-queue

bridge-group 1

!

ip classless

no ip http server

!

!

!

control-plane

!

bridge 1 protocol ieee

!

router2

!

!

hostname xxx

!

boot-start-marker

boot-end-marker

!

no logging on

enable secret xxxx

!

no aaa new-model

ip subnet-zero

!

!

!

!

ip cef

no scripting tcl init

no scripting tcl encdir

!

!

!

!

interface FastEthernet0

no ip address

speed auto

bridge-group 1

!

interface Serial0

description connected to Bahrain

bandwidth 128

bridge-group 1

!

ip classless

no ip http server

!

!

!

!

bridge 1 protocol ieee

!

[a.awan]

If you do not want to configuring routing and bridging simultaneously then turn routing off on the router by using the command 'no ip routing'. If you want routing functionality in addition to the capability to bridge ip then use IRB as recommended earlier.

[Kevin Dorrell]

OK Savio, I don't see anything wrong with that. It seems to be practically identical to the example in the document I sent you, so I cannot work out what is wrong.

Please could you do a show int S0, a show bridge verbose, and a show arp on each router? Perhaps that will give us a clue.

Kevin Dorrell

Luxembourg

[a.awan]

I am pretty sure the problem lies in the fact that he is trying to bridge IP while the router is trying to route it. By default ip routing is enabled and unless you explicitly turn it off or use another bridging mechanism like IRB or older CRB, you will not be able to bridge the IP traffic. Other non routable protocols will be bridged but IP will be routed by default. Like i suggested earlier turn routing off and then see if you can ping the remote ip address.

[Kevin Dorrell]

Atif,

Out of curiosity:

If he does bridge irb will the bridge start working even if he does not have any bvi interfaces yet to connect the bridge to the router?

Also, will it be bridging IPX/AppleTalk/DecNet/etc already? Is it just IP that is excluded from the bridge at the moment? Or is any bridging mutually exclusive with ip routing unless you have CRB or IRB?

Kevin Dorrell

Luxembourg

[a.awan]

Bridging should work without having to configure the associated BVI interface (provided he enters the bridge irb command like you mentioned).

When you configure bridge irb then everything is bridged within the bridge group by default. Routing for IP will need to be configured explicitly using the brige route ip command thereby tying it to the BVI for off network traffic. Note that this behavior differs from normal bridging where IP is routed by default (unless no ip routing is configured).

To answer your second question yes i believe everything other than IP is bridged by default and does not require ip routing to be turned off to function properly.

[saviopereira]

thankyou kevin

after entering bridge irb it started working

[markmonteleone_2]

Anything stopping to from working if the interfaces are dot1q subinterfaces?

[paolo bevilacqua]

8 years old thread - Please open new threads for new problems.