GRE Tunnel redundancy over Reduntant WAN link using SLA Monitoring

[sreeraj.murali]

Hi,

Request some ones inputs in configuring GRE Tunnel redundancy on Cisco VPN Router over Multiple WAN Links. I read, it is possible using SLA Monitoring. Please provide with the Cisco online documentation guide in achieving the same.

Or else, please suggest other ways to achieve the same, if not using SLA Monitoring.

Thanks & Regards

Sreeraj Murali

[nspasov]

Hello Sreeraj-

Are you able to run dynamic routing protocol over the GRE tunnels? If so, you can explore running something like EIGRP and use dynamic routing for things like failover, load-sharing, etc. 

I hope this helps!

Thank you for rating helpful posts!

[sreeraj.murali]

Hi Neno Spasov, We do advertise the networks over the tunnel using EIGRP routing. We need to have the Tunnel choose the active Internet leased line interface, at the local site. How we can achieve that. Please share any Cisco documentation, if you have. Thanks, Sreeraj

[nspasov]

EIGRP will automatically load balance over 6 equal-cost links/paths. Thus, if you have EIGRP running over both tunnels then your EIGRP table/topology should be showing two equal routes to those networks. You can confirm this by issuing show ip route eigrp and show ip eigrp topology

If that is the case then all you will need to do is make one of the tunnel interfaces less preferred than the other in EIGRP. You can accomplish this by manipulating one of the EIGRP metrics that is used to calculate the cost. One of the easiest way to do this is to alter the bandwidth or the delay on the tunnel interface. 

For more information on this you can reference the following link:

http://www.cisco.com/c/en/us/support/docs/ip/enhanced-interior-gateway-routing-protocol-eigrp/13673-14.html

I hope this helps!

Thank you for rating helpful posts!

[sreeraj.murali]

Hi, Thanks for suggesting. This solution will help, if we have multiple tunnel configured.

I am here trying to explore the option of having "single tunnel" "using multiple source Interface" each from different Service provider" at the our local side. Hope you are clear on the scenario.

Please find the below link,which clarifies the topology. Instead of Cisco ASA, we are having Cisco Router.

https://supportforums.cisco.com/sites/default/files/legacy/0/5/2/85250-VPN%20redundancy%20network%20diagram.png

Please suggest.