I have a crude internet loadbalance setup using two different ISPs with assigned address spaces and two edge routers doing NAT. The two edge routers connect to a 3rd router acting as loadbalancer using two equal default routes with CEF per destination. I run EIGRP between these three routers. The loadbalancer then connects to a set of redundant ASA5510s outside the corporate vlans. For inbound connections to our Internet facing servers, I use one DNS server for each ISP assigned space, dual internal IPs on the servers, PBR on the loadbalancer to route server resonses to the edge router where the original request came through.
This low-cost solution has worked fairly well except for the browns-outs further upstream.
To tackle the brownout issues and achieve better, dynamic outbound loadbalance, I purchased two 1811 routers (to replace my old 2610 and 2500s) and plan to implement OER with BGP. We do own a /24 address and both ISPs (ATT and Roadrunner) allow BGP for class C size.
My main concern is whether asymmetric routing will affect our Internet applications. Obviously, web browsing is not affected. But we use video streaming sites for training purposes. We also have VPN connections, Webex for web conferencing, and persistent HTTPS for Extranet applications.
Moreover, since OER dynamically adjusts load on each ISP link, it may move one session from an over-subscribed link to the other, thus creating asymmetric routing in the middle of a session. How will this impact some of the above applications?
I need to replacing my old routers with the two new 1811 routers by the end of the month but I'd like to improve my current Internet setup if I could.
Any input from you will be greatly appreciated!