How do I force OSPF to prefer a certain route when there are active redundant, meshed routes?
Posted on 2009-02-17
I tried to connect multiple sites with redundant, meshed routes and OSPF was preferring some routes over others in what seems to be an uncontrolled fashion. I would like to give routing preferences and only use alternative route when a circuit goes down.
For example, A-B connects over a 54Mbps wireless. A-C connects over a 1.5Mbps MPLS. B-C connects over a 1.5Mbps T1 via GRE/IPsec tunnel. For some reason, OSPF tells C that the best route is to B, two hops away, not A, one hop away.
I tried to set Priority 1 on A-C at C and Priority 100 on B-C at same. Doesn't seem to change OSPF preference. Perhaps I'm using the wrong keyword. Cisco 1841 routers.
Please note that this is more complicated than the above. I have A/B, A/C, A/D, A/E, etc. and there are B/C, B/D, B/E, etc. in case A fails. Furthermore, there are two routers at A and B, one connecting A/B only (PTP wireless) and one connecting to the Internet/MPLS with tunnels to each location, including between A/B (in case the PTP fails).
The simpliest term is that each location (C, D, etc.) have connections to A. Some locations have two connections, a MPLS and an IPsec VPN through Internet. All location also have an IPsec VPN through Internet to B, too. So, that's a total of 2 (no MPLS) or 3 (with MPLS) connections per location. I need OSPF at other locations to prefer MPLS (if applicable), IPsec to A and finally IPsec to B in that order. No load balancing, just auto-update OSPF only when circuits/routers go down.
As for A/B, they should prefer the 54Mbps PTP route then the IPsec VPN route between themselves.
Ashland Support Group