Binding together 2 T1's

[sobak]

I have a cisco 7120 that we would like to increase our bandwidth. We are thinking about adding a second T1 to the router to achive this. My question is can this be done? and can someone point me in the right direction to configure this. Hardware is not an issue, I know my 7120 will handle this but I don't know where to start.

Thanks

david e
*end users are just like computers, some you can work with...others just need a simple reBOOTing to fix their problems.*

 

[webnetwiz]

Did you want to get the T1 from the same ISP or a different ISP?

If the same ISP, find out if they do multiplexing.
If a different ISP, then you're looking at running BGP with peering agreements between you and your 2 ISPs. Make sure your 7120 has enough RAM to hold all the routes. The BGP option will give you load balancing + failover capabilities.

 

[sobak]

We want to keep the T1's with the same ISP, our primary goal for this is to increase the bandwidth of our current VPN traffic. Taking the VPN outside to a different provider slows down the response time. We have found keeping it on the same provider gives us faster response time.

I've figured out how to do load balancing but now the VPN's come into play. In my current GRE tunnel I reference my Serial Port as the source address, if I do the same with the two T1's I'm afraid I will only be able to establish the VPN over 1 of the T1's and not both. I'm researching this extensively and still not any closer than where I started.

I've read about the Multilink-Group interface and that looks like the way I need to go but I'm not sure at this point, I'm still researching.

Any thought on this, am I on the right track or should I just hang up my admin hat
david e
*end users are just like computers, some you can work with...others just need a simple reBOOTing to fix their problems.*

 

[nix45]

We're doing the same thing as you with the dual-T1's on a Cisco 3620 router. Our ISP (AT&T) sent us a sample config...


version 12.0
service timestamps debug uptime
service timestamps log datetime localtime
service password-encryption
!
!
ip subnet-zero
ip cef
no ip finger
no ip domain-lookup
!
interface Serial0/0
description connection to AT&T backbone
bandwidth 1536
ip address 10.0.0.2 255.255.255.252
ip access-group 101 in
no ip directed-broadcast
ip load-sharing per-packet
encapsulation ppp
no ip mroute-cache
!
interface Serial0/1
description connection to AT&T backbone
bandwidth 1536
ip address 10.0.0.6 255.255.255.252
ip access-group 101 in
no ip directed-broadcast
ip load-sharing per-packet
encapsulation ppp
no ip mroute-cache
service-module t1 remote-alarm-enable
!
interface FastEthernet2/0
description connection to customer LAN
ip address 192.168.0.1 255.255.255.0
no ip directed-broadcast
speed auto
duplex auto
!
ip classless
ip route 0.0.0.0 0.0.0.0 Serial0/0
ip route 0.0.0.0 0.0.0.0 Serial0/1
no ip http server
!



Chris

 

[sobak]

Chris

Thanks for posting the config, that helps out a lot. One of my problems that I find myself running into are my GRE VPN's though. My source address references an interface, at this point I think if I reference one interface then the GRE Tunnel will only establish on one of the serial interfaces and not over both. What I'm attempting to do may not even be possible but I can't see I'm the first person to ever run into this problem. I'm the type of person where there's a way I got to find it out. Got any additional thought on this one ??? david e
*end users are just like computers, some you can work with...others just need a simple reBOOTing to fix their problems.*

 

[rburke]

I don't know if this is possible, but could the GRE reference a Loopback interface IP as the Source Address? Like I said, I don't know if this is possible, but that way it doesn't matter which T1 is goes over to get to the Loopback. Just a fleeting moment idea.

Burke