I am deploying two 3750E's in my netwrok. One of the 3750E switch at site A will have two eBGP networks. The 3750E on the second site willl have 1 eBGP peering. All the 3 eBGP peerings are with the same company only. So, on all the three links I will have the same network prefixes coming in. The two 3750E's are connected with each other and will be runnintg iBGP between the.
What I want is that if link1 goes down at site A then the traffic shoul go through the link 2 in Site A. Only when both the links in site A are down then only the traffic should be routed to site B. I can achieve this using weights in BGP. My main problem is hopw do I configure HSRP between the Site A and Site B.
--> If I use route tracking for the remote subnet then HSRP won't work because of the iBGP between Site A and Site B. So even if both the links go down at Site A the subnet will be still available via the iBGP connection. HSRP won't fail over.
--> If I use interface tracking then which interface should I track. If I track the WAN interface the when link 1 goes down then HSRP kicks in and starts sending the traffic towards SIte B even though Link 2 is up.
Link 1 and Link 2
Traffic to moce out on Link 1 if it fails then Link 2 and if both LInk 1 and Link 2 fails then only Link 3 should come into the picture.