Setting up Cisco 1601s for bridging over Point to Point T1

[cellzdirect]

I have two Cisco 1601s and a point to point T1 line between them. I'd like to set up a bridge between them to conserve my allocated IP addresses. I have not touched a Cisco in about two years, and have entirely forgotten what I need to do from the enable prompt. A quick google and tek-tips search came up with very little help for bridging.

[ul]
[li]Question: How the heck do I set this up? (simpler the better)[/li]

[li]Question 2: Would it be better to route? (although I'd prefer to bridge due to lack of IP addresses assigned to this subnet)[/li]

[li]Question 3: I read another post that said I could use a T1 crossover cable between the two interfaces for testing... will that work without line timing, or do the routers work that out between themselves?[/li]
[/ul]

 

[BuckWeet]

you could implement 'NAT' to conserve your IP addressed, broadcasts across a T1 = BAD


but to do it

you need to go into your ethernet ports and serial ports and do a command like "bridge-group *" * = group number.


BuckWeet

 

[cellzdirect]

The address space is separated from the space that generates many broadcasts... I'm not worried about broadcast overhead at all.

If anyone could point me to a config anywhere, that'd be great - I don't want to put someone out so they spend the time to write a config from scratch... my eyes are bleeding from reading cisco manuals and searching the web. (I'm obviusly just searching the wrong areas, I'm sure the answer is out there somewhere.)

 

[cellzdirect]

Despite the profuse bleeding from the eyes, I have bridging up and running now.

I have another issue, though - (maybe deserves its own topic, but I'll deal with that if necessary.) The T1 crossover cable works on its own - when I unplug to simulate a telco worker tripping on my line, the routers see the line protocol down and then turn the interface itself down. When I plug it back in again, the routers DO NOT automatically see the line up again.

How can I configure them to automatically check the interface when down to see if it's back up again?

Running config included below (both router configurations are identical except hostname and IP address):

-------------------
[tt]
loginrouter#sh run
Building configuration...

Current configuration:
!
version 11.2
no service password-encryption
no service udp-small-servers
no service tcp-small-servers
!
hostname loginrouter
!
enable secret (it's a secret)
!
ip subnet-zero
no ip routing
no ip domain-lookup
!
interface Ethernet0
ip address 1.2.3.4 255.255.255.240
no ip route-cache
no logging event subif-link-status
bridge-group 1
!
interface Serial0
no ip address
no ip route-cache
no logging event subif-link-status
shutdown
!
interface Serial1
description Leased line
ip address 1.2.3.4 255.255.255.240
no ip route-cache
no logging event subif-link-status
no fair-queue
bridge-group 1
!
no ip classless
ip http server
bridge 1 protocol ieee
!
line con 0
password (it's a secret)
login
line vty 0 4
password (it's also a secret)
login
!
end

loginrouter#
[/tt]