Redundency set up ideas

DevilWAH

Hi,

is it possible on a router to influence the default gateway a packet takes based on the source IP address.

For example Say I have 3 Routers

Router A is connected on F0/1 to Router B and on F2/0 to router C

I want to say on router A,

IF traffic is from Subnet Y and you don't have a specific route use Router B as the default route. On the other hand if its from Subnet Z and you don't have a specific route then use Router C as the default route.

I just playing with it now but if any one wants to give me any pointers I would be greatful.

Cheers

DevilWAH

Sorry found it

"set ip default next-hop"

Simple

not sure how i can influence this based on failure further up the line though. For example if Router C in the example below loses its connections upstream from Router A, Router A will still try to forward data to it as the next hop will still be live. I suppose its just using SLA's to monitor things and using that to make sure switch over happens.

What I want to say is

set ip next-hop verify-availability 10.1.1.1 1 track 10

but using the "ip default next-hop " command instead.

any ideas ?

Dieg0M

You can pretty much do anything you can imagine with a combination of IP SLA's and EEM's.

DevilWAH

yer i was hopping to get away with out using emm, much as its fun to play with i feel there should be a built in way to achieve this.

I just feel like i whould be able to say,

if it matches Access list A user default router A as next hop
if it matches Access list B use default router B as next hop

which i can.

Then set a tracking object to a remote IP upstream of Router A and B, and used them to check the default next hop is fully valid and take action as required.

The easy way to do this with out emm is simply to on router A and B set a tracking object upstream and if it fails, shut down the interface downstream so the nexthop verification fails and it fails over to the other route.

jdballinger

What about using Policy Based Routing? You can get pretty granular with that I think. I haven't ever configured it, but I skimmed the docs looking at maybe using it as a way of sending guest wifi traffic out our backup links instead of the primary.