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BGP -2 ISPs peer private-as


If we have 1. two ISP links terminated on two routers

               2. these two ISP has given different pool of /28

               3. We are BGP peering with ISP router using a private AS given to us by each ISP.

In this situation is there any way to load balance outgoing internet connections or incoming internet connections.

These routers are 1800 series os NAT on these routers is not possible. or difficult  We will do the NAT on ASA which sits just adjacent to these routers. And then forward the traffic to corresponding ISP router. This is one way we can think about load balancing for outbound. Is there any way to track if ISP links are up or down on ASA. (like  sla and rtr on routers) And then take corresponding action of NAT and forwarding those packets to ISP router.

For incoming is there any way to adjust the traffic between two ISP links. (Given that they have given us the seperate pool and private AS).

One soluation probably is to use DNS for load balancing.  If resource  ( A records ) is made available with two different IP from two different ISP. But in this case, there is a problem if one ISP link is down. (In first place  is it possible to do the name to different IP address resolution using DNS with some configuration) . Do ISP DNS provide such services. I am not sure but cisco "site selector" can be used in such cases.

Please share the experience.



Hall of Fame Super Silver

Re: BGP -2 ISPs peer private-as

Hello Subodh,

there is this white paper about multihoming with NAT that covers multiple aspects

Hope to help