WAN Redundancy

Published on August 15 2013

Question:

I know that with Cisco 2911-SEC Serial interfaces I can do MLPPP but so far what I have seen says that the serial interface get a "no IP address" and joined to the multilink bundle which has the IP address. What can I do to bundle something like a cable Internet connection and DSL or metro E? All would have an Ethernet handoffs but all of these types of circuits also require, I think, and IP address.

Goal would be to load share across the circuits or second choice, to have the backup link activate as soon as the primary link goes down.

Answer:

Yes you can achieve that by using static routes with object tacking, the example below will show you

more details

Normally you will need two default routes one that points to the main ISP "Lets say metro ethernet " and the other points to the second back ISP DSL " than you have a link with object tracking on the main ISP normally you should give the main route lower administrative distance

for example :

ip sla 1

icmp-echo 8.8.8.8 source-interface FastEthernet0 " interface with the main ISP"

timeout 500

threshold 500

frequency 3

ip sla schedule 1life forever start-time now

track 1 ip sla 1 reachability

delay down 10 up 20

ip route 0.0.0.0 0.0.0.0 10.10.10.1 track 1 " Main route"

ip route 0.0.0.0 0.0.0.0 192.168.2.1 7 "Backup route"

In this case the main route to the ISP went down the backup route will take over and be installed in the routing table