I have a Cisco 2801 that has 2 different ISPs using BGP. This router also serves as an internal router for vlans and a firewall. Currently I have one of the providers sending me their client routes. However, traffic is not going down that line at all. I have also configured several vlans to use a particular line via route-map. It works fine as I do a tracert it goes down the proper line. The problem is how can I get return traffic to use the same line.
Let's say BGP believes (for lack of a better word) line 1 to be the shortest path so by default all traffic would go down that line. To achieve some load-sharing, I force my vlan to go down line 2. However, when traffic I generate is to come back to me it comes down line 1. Normally, this would be fine but there is enough aggregate traffic where I need to do something. Hence, my thinking of doing a manual load-share, if you will, by jockeying which vlans go down which line but if all the traffic comes back the same line (line 1 in this example), I really don't gain anything.
I suppose I could force all outbound traffic to go down line 2 and have line 1 handle the return traffic. However, this solution doesn't sound all that appealing. Given I am only advertising a single class C address space I don't know if some sort of filtering would be the answer. I suppose I could break up that class C into 2 subnets and advertise 1 block with line 1 as the primary and the 2nd block with line 2 as the primary.
Just looking for ideas at this point.