06-12-2012 05:55 AM - edited 03-04-2019 04:39 PM
We copy large amounts of data from a host in site C to a host at subnet 10.234.0.0/22. I have two paths to get from C to the host. One is perfered by us due to larger bandwidth. The link between C -B is a gig and B-A is a Gig. The link between C-Z is 100 meg.
Both of the A and Z routers are on the same OSPF area on the LAN side and different BGP AS on the WAN side. I want to advertise the route from Z to be a higher metric so it is not the perfered route. I want traffic from teh 10.232.x.x network to chose the C-B, B-A. The C-Z is an alternate backup for this data copy.
How can I advertise from the A and Z router the 10.234.0.0/22 so it is a higher metric from Z than A?
06-12-2012 06:17 AM
Hi,
don't forget you need to influence both traffic directions.
If you need just a temporary solution, the easiest way would be:
Configure two static routes on your router A:
One for the host in 10.232.0.0/16 subnet, using 10.32.255.1 as next-hop. Redistribute this route to OSPF (but not to BGP!).
Second for the host in 10.234.0.x/22, using 10.234.0.7 as next-hop. Redistribute this route to BGP (buit not to OSPF!).
As "longest match wins", router A will be always preferred for the communicatiopn between those two hosts.
Remopve those host static routes when finished with your file transfer.
If you need a long-term solution, you should reconfigure the OSPF/BGP mutual redistribution to advertise 10.234.0.x/22 subnet with worse attributes (by AS prepending, e.g.) from router Z to BGP.
And also to advertise the 10.232.0.0/16 with worse OSPF metric from router Z to the OSPF cloud.
But this is a little tricky and you need to know the curent metrics used for the routes.
HTH,
Milan
06-12-2012 06:38 AM
Hi,
Rather than influencing the Routing Protocols, you could use Policy Based Routing to achieve this.
Kind regards,
Paul
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