Two Internet Connections

[dbrill001]

We have 2 buildings 2103 and 2080. We have a fiber connection between them. the catalyst 3560 X Series at 2103 does all the routing. The Catalyst 3560 at 2080 is in Layer 2 mode. 2103 currently has internet from our ISP. We currently have 12 vlans between the two buildings and we use RIP to do all the routing. We have to NSA 240 Sonicwalls for each side.

We are going to sign a contract with a second ISP to provide Internet and SIP lines to the 2080 building. When that happens my boss would like me to change the network to route 2103 internet traffic out the old ISP and 2080 internet traffic out the new ISP (I will be moving our Lync Servers over to this connection). If either is to fail then they need to fail over to the other connection.

I have heard we can do this with EIGRP but not sure how to go from RIP to EIGRP and I assume everything will be down while I do it. Can I go ahead and start setting it up now so I have some of the work done before hand? What information did I forget to add? I am hoping I can get that done then come back and setup the BGP for the external.

[Reza Sharifi]

Questions;

Is the 3560x switch in 2103 connected to the service provider?

Are you planning to connect the other 3560 in 2080 to the new provider?

Are you running NAT? If yes what device is doing the NAT?

If yes, you have to make sure that the 3560x switches have the right license installed first.  If you currently don't have "IP Services" license on these devices you are not going to be able to run BGP with the provider now or in the feature.

You can certainly do what your boss wants to do, but need to do some design and planning.

Once you have the second provider installed, you can run BGP with the provider or static routes.

You also need a connection between the 2 devices for fail-over and redundancy.

HTH

[dbrill001]

Is the 3560x switch in 2103 connected to the service provider? Yes, Old Provider with Juniper Firewall

Are you planning to connect the other 3560 in 2080 to the new provider? Yes, Once installed with Juniper Firewall

Are you running NAT? Yes, If yes what device is doing the NAT? Juniper Firewall NSA 240

[Ben Gartland]

Hi,

The easiest way of doing this is to lower the AD of RIP on your RIP enabled routers. I recommend setting RIP to AD of 80, which will be lower than EIGRP's internal metric of 90.

Now you can set EIGRP with no worries about the routes entering the routing table. You can check routes are advertised and learnt correctly in EIGRP, then when ready you can just revert the RIP AD back to default.

EIGRP summary routes have an AD of 5,  but that is locally significant,  advertised summary routes still are seen on adjacent routers with an AD of 90.

By doing this, you get everything up and running and downtime will be minimised. 

Hope this helps. 

Ben