Router Multiple Dual Wan Ports Backup Settings

Today, I am going to share how to create multiple dual wan ports in the router. This method is essential for the router upstream links. Because if one of the links has a problem, then customer can still connect to their head office using the other upstream link. The configuration can be found below :

The customer network has dual multiple wan ports that connect to ISP A (BGP 33) and ISP B (BGP 44). So as the head office ports configurations. In head office, there is one ip address which is advertised to the BGP (5.5.5.5). That IP pretend as the server in the head office and we are aiming to that IP from the customer side. We are using BGP as the connection to all network. Because BGP is flexible and has a lot of advantages. This configuration also maintain as a hot backup for the router upstream links.

BGP connection inside R2 :

There are two established BGP connection and there are up. Both of them receive one prefix from R5, we can see below :

The link that we prefer as the main link is through ISP A. So we set weight 1000 for ISP A. ISP B will remain standby in case there is problem with ISP A link.

Then we try to simulate the backup mechanism by shutting down the R3 Fa0/0, so the bgp connection from R2 to R3 will be dead. R2 traffic will go through ISP B, we can see from the picture below :

What will happen if we active ISP A link again ? R2 traffic will back to normal again, the traffic will flow through ISP A. We can see the end result below :

 

Okey, this is for today sharing session. I will try to write more again soon. This is the link to download gns3 configuration.

http://www.4shared.com/rar/mX0WZiGD/Router_Dual_Multiple_Wan_Ports.html

You can try it at home. Good luck.

Thanks