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Using an 1841 as a T1 Ethernet Handoff?

cjr
Level 1
Level 1

This got tossed on my lap and I am rushing to try and figure out how (or if even possible) to do this. I'm a far cry from adapt at this.

Basically, we have two T1's that are connected to an 1841. They are setup on the serial interfaces using PPP encapsulation and connected via Multilink (they are confirmed working). What I'd like to do is simply pass that connection on to our main router which currently does all the routing via one of the 1841 Ethernet ports. In essence letting the 1841 act as a bridge or pass through for the connection.

An engineer from the T1 provider has told us that we'll need to use two Ethernet connections, a host of routing rules (for this portion of our network) and one of the connections will require a cross-over cable so that incoming traffic comes on one interface and outgoing on another. We have a router that handles our firewalls, other internet connections and WAN traffic already, I'd rather it handle the routing so we have one last place to worry about updating things.

Can the 1841 just act like a bridge or Ethernet hand off with the multilink? Is this possible?

1 Accepted Solution

Accepted Solutions

Are you physically able to terminate the T1 connections currently going into your 1841 router to your other main router instead? If so, there's your solution right here.

If for cabling distance/hardware reasons you can't terminate the MLPPP on your "main" router and it needs to remain terminated on your 1841 router, then either configure static routing between your main router & 1841 router, or establish a dynamic routing protocol (RIP, EIGRP, OSPF, etc.) between them.

If dynamic, advertise the networks between the 1841 and main router and connectivity will be able to pass.

This is not a bridge, simply routing from one network to another.

View solution in original post

4 Replies 4

dgroscost
Level 4
Level 4

If you're looking to hand it off to the other router, and assuming they are all within ethernet range, why not terminate the Multilink bundle on your main router? You can bridge both ends of the MLPPP if you really want, but as for passing it off you might be better off just setting up static routes so you don't have to maintain a bridged network and/or another dynamic routing protocol.

That sounds like what we are wanting to do. I've been trying to find information on how to accomplish this and it's not been an easy task.

I guess the question really is, how do you terminate the multilink bundle from the 1841 to the router? Everyone I've spoken with indicate you have to create a setup similar to the one in my original post yet your solution sounds far easier and less cumbersome which was our original goal.

Could you point me to some documentation or examples that might help me set this up (or understand it)? This is a gray area of networking I'd never really wanted to get in to but I guess I'm being forced to learn. :)

Are you physically able to terminate the T1 connections currently going into your 1841 router to your other main router instead? If so, there's your solution right here.

If for cabling distance/hardware reasons you can't terminate the MLPPP on your "main" router and it needs to remain terminated on your 1841 router, then either configure static routing between your main router & 1841 router, or establish a dynamic routing protocol (RIP, EIGRP, OSPF, etc.) between them.

If dynamic, advertise the networks between the 1841 and main router and connectivity will be able to pass.

This is not a bridge, simply routing from one network to another.

That's the problem, we have no other way to terminate the T1 connections besides the 1841.

So it appears we'll have to deal with the 1841 and having it route traffic when all we need is just a termination and hand-off.

We just wanted to avoid any routing on the 1841 as it's just one more place for our small shop to have to deal with. For now, I'll setup static routes since everything is in flux and deal with a more permanent solution later.

Thanks for the help and advice.

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