Bridging with Cisco 2600s and serial interfaces

[jfreeman]

Hello,

I have two Cisco 2621 routers. Each router has two Fast Ethernet interfaces as well as one WIC-1T serial adapter. The routers are connected directly to one another by means of a serial cable between their WIC-1Ts. I want to configure both routers, connected by the serial link, to function as a single transparent bridge between two Fast Ethernet networks. I realize this seems somewhat silly - the purpose is a test lab scenario in which equipment is limited and I need to test the performance of a connection made over this serial link (a type of rudimentary WAN simulation).

I have read the Cisco documentation and have been able to set up bridging in the following ways:

1. Simple bridging between FastEthernet0/0 and FastEthernet0/1 on the same router.

2. Bridging between the FastEthernet0/0 interfaces across both routers, with the routers connected by their FastEthernet0/1 interfaces rather than by the serial cable.

However, when I remove the Ethernet link between the two routers and replace it with the serial link, the bridge no longer works. This serial link is known to work; I have personally used it in another configuration (not involving bridging).

Here's how I've tried configuring both routers so far:

Interface FastEthernet0/0:
ip address 192.168.1.200 255.255.255.0
bridge-group 1

Interface Serial0/0:
ip address 192.168.1.200 255.255.255.0 (have also tried no ip address)
bridge-group 1
encapsulation ppp

Global:
no ip routing
bridge 1 protocol ieee

And, no luck. I really don't have the background in dealing with much other than Ethernet, so I'm at a loss as to what to try with these serial interfaces. Can anyone help?

Thanks,
Josh Freeman

 

[andf1]

ROUTER 1:
Interface FastEthernet0/0:
ip address 192.168.1.1 255.255.255.0
bridge-group 1

Interface Serial0/0:
ip address 192.168.1.2 255.255.255.0
bridge-group 1
encapsulation ppp

no ip routing
bridge 1 protocol ieee

ROUTER 2:
Interface FastEthernet0/0:
ip address 192.168.1.4 255.255.255.0
bridge-group 1

Interface Serial0/0:
ip address 192.168.1.3 255.255.255.0
bridge-group 1
encapsulation ppp

no ip routing
bridge 1 protocol ieee

The above should work. If it does not, make sure you can ping the serial port of one router from another router. Use extended ping while testing.

andf1

 

[jfreeman]

Thanks for the help. It now appears that the problem is a failure of the serial link not related to bridging. Assuming I'm beginning with a factory-defaults router configuration, can somebody help me get the two WIC-1Ts talking to one another?

I can get both interfaces up (green light on both cards) and I've assigned IP addresses to both, but cannot ping one from the other. What have I left out?

 

[phoyle]

What kind of serial cables are you using? Attached to one router needs to be a DCE cable while the other needs to be a DTE Cable.

On the router using the DCE cable you need to configure a clock rate 1300000 (to emulate a T1).

Once this is set up then the clocking should work and the circuit should cone up.

Paul Hoyle, CCNP/CCAI

 

[jfreeman]

It's working! Thanks for the help. For some reason line protocol was down on the serial interfaces. Resetting the configuration and stepping back through it fixed that problem... who knows what I'd missed the first time. Then it was just a matter of setting up the bridge group and changing the clock rate.

Thanks again for your time and suggestions.

 

[akintolad]

I,am trying to configure transparent bridging between two 2611 cisco routers.After the configuration of the two routers i still can't ping across the two routers, also i found out that i can't ping either of the serial interfaces of the two routers, even from within each routers.Your material was quite helpful, but i just seems to be getting something messed up somewhere.Below is my router configuration

Rouetr1
controller E1 0/0
clock source internal
linecode ami
channel-group 0 timeslots 1

interface fastethernet0/0
ip address 10.107.0.251 255.255.255.0
speed 100
full-duplex
bridge-group 1

interface serial0/0:0
bandwidth 64
ip address 10.107.0.252 255.255.255.0
encapsulation ppp
no keepalive
bridge-group 1

no ip routing
bridge 1 protocol ieee


ROUTER2
controller E1 0/0
linecode ami
channel-group 0 timeslots 1

interface fastethernet0/0
ip address 10.107.0.253 255.255.255.0
speed 100
full-duplex
bridge-group 1

interface serial0/0:0
bandwidth 64
ip address 10.107.0.254 255.255.255.0
encapsulation ppp
no keepalive
bridge-group 1

no ip routing
bridge 1 protocol ieee

PLEASE GET BACK VERY FAST BECAUSE I HAVE TO IMPLEMENT THIS FIRST THING ON MONDAY MORNING. YOUR HELP WILL REALLY BE APPRECIATED.