Tracking LAN connectivity to a subnet

[Xenogan28]

Hello.. I am trying to work through a LAN fail-over situation. Currently I have 2 routers running BGP over MPLS. I set up monitoring and tracking using IP SLA to ping the eBGP peer. If pings fail, my active MPLS router will failover to my secondary.

What I am now working on is this: I want to be able to fail over the LAN side when traffic is not reaching hosts within my directly connected subnet. I already have HSRP configured with an active/standby topology but this is just going to fail-over if reachability between the active and standby is not allowed.. what if the failure is further down, taking place in one of the access layer switches? Is there a way I can monitor end-to-end connectivity between my gateway and multiple hosts within a subnet? Without defining these multiple hosts by IP because they may be removed or additional hosts added at any time.

Maybe by somehow monitoring the frequency of packets received on my LAN side interface?

[sarathpa]

Hi,

You can configure the loopback address on all access switches and monitor the ip sla.

[e.ciollaro]

Hi,

usually I don't like tracking as a failover technology;considering that you want to "fail over" make me thing that your network has some kind of redundancy. If it is the case and you properly designed the network (as in the attached draft) you have redundancy and probably you don't need tracking. In case of a link failure, STP change the layer 2 topology and, after that, your access switch is reachable again. In case of a major failure to the switch usually there is nothing to do because host are connect to a single switch. 

At the opposite if you haven't redundancy, probably you can't failover. Could you upload your architecture so I can have a better understanding of the topology ?

Bye,

enrico