OSPF - Load Balancing

Unanswered Question
Jan 24th, 2008


We have the following setup:

RTRA & RTRB located in site A both are OC48 connections.

RTRA connects to RTR1 in site B, then to internet

RTRB connects to RTR2 in site C, then site C connects to Site B and then to internet via RTR2.

Link from RTRA to RTR1 is saturated. We would like to load balance traffic using both RTRA & RTRB in site A. Would changing the cost on RTRA accomplish this? OSPF is the routing protocol and there is only 1 area, area 0.


I have this problem too.
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Edison Ortiz Thu, 01/24/2008 - 16:38

Yes, OSPF costing the interface on RTRA facing RTR1 to be equal to the aggregated cost seen on RTRB towards RTR1 should fix the issue.

As for the internet (default route), is that being injected into OSPF as an external route ?



emrivera01 Thu, 01/24/2008 - 16:57

RTRB does not connect to RTR1. We have 2 routers each in site A, Site B & Site C.

Site A RTR1 ---- Site B RTR1 ---- Level 3

Site A RTR2 ---- Site C RTR1 ---- Site A RTR2 ---- LVL 3

We run BGP at the edge and receive full internet routing tables peering with level 3. We are an ISP as for the line of business. default route is not being injected into OSPF.

I will try what you suggested. thank you for your help.


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