Sam
To come up with a really good design would require knowing some things about your network that you have not told us. But based on what you have provided here I have the following advice:
- It is not necessary that your 7206 and your 1700 be directly connected. They will run a BGP session between these routers and it will be an IBGP session (both routers in the same AS). It is not necessary for IBGP peers to be directly connected. The connection between 7206 and ISPA and the connection between the 1700 and ISPB are dirrectly connected and will be EBGP sessions. It is generally better if EBGP peers are directly connected.
- I would be very cautious about running BGP on the 1700. The memory requirements and the processing requirements for participating in Internet BGP can easily be greater than the capability of the 1700. I would suggest that the 1700 only accept a default route from ISPB. That will greatly reduce the memory requirement and the processing requirement on the 1700.
- I am not sure that I would want to load balance between the 7206 and the 1700. I might prefer to have the 7206 be primary and handle all the Internet traffic if it were available and use the 1700 as fallback if needed. But if you want to do load balancing I would have both the 7206 and the 1700 receive only a default route from their ISP. They can make their version of the default route available to their part of the network. And if one of the routers failed you could have that part of the network use the default route from the other router. The details of how to do that would depend on what interior routing protocol you are running.
HTH
Rick
HTH
Rick
