OSPF - Load balancing

[june03]

Hi,

We have the following setup, all OC48 links:

Site A RTR1 ---- Site B RTR1 ---- Level 3
Site A RTR2 ---- Site C RTR1 ---- Site A RTR2 ---- Level 3

Currently, link between Site A RTR1 to Site B RTR1 is saturated. Site A RTR2 to Site C RTR1 does not have much traffic on it. Would adjusting the cost between Site A RTR1 & Site B RTR1 help out in this case? We are running OSPF with only 1 area, area 0.

Thanks.

june03

 

[brianinms]

Perhaps your diagram isn't accurate. Cost wont change the saturation of the link.

 

[burtsbees]

How many routers in area 0? Also, if they are all advertising, then you'd expect all links to be saturated (if OSPF indeed was causing it), but I HIGHLY doubt it is, as brian indicates.
Show more info, and perhaps a sh interface of the two saturated links and sh run of both routers.

Burt

 

[june03]

Diagram is just showing 3 sites connecting. We have several sites. Look at the attached link, picture towards the end on the right side.

several customers, CPE connect to a few cisco UBR1000 routers, who then connect to Cisco GSR's at their respected site, example site A & Site C. Cisco GSR's at each site connect to other GSRs via point to point OC48 connecting sites together. They all one way or another mesh together to connect to both GSRs at Site B which lead all traffic out to internet. So looking at just the 3 sites only:

Site A RTR1 ---- Site B RTR1 ---- Level 3
Site A RTR2 ---- Site C RTR1 ---- Site A RTR2 ---- Level 3

All internet bound traffic that is generated from site A, is going out via site A RTR1. I would like to send some of that traffic out using site A rtr2.

june03

 

[brianinms]

If Site A RTR 2 doesn't have a connection to Site B RTR 1, then there is no way traffic will take that path. OSPF = Open shortest path first. You must first have a path for OSPF to even consider it.

 

[june03]

to get to internet, site A RTR2 has to go extra hop via Site C RTR 1, then to Site A RTR2 and off to internet. RTR1 in site A only has to hit RTR1 in site B then off to internet. Since all the routers behind site A RTR1 & RTR 2 are taking the router via RTR1 due to shortest path, Last night i adjusted the cost between site A RTR1 & Site B RTR1 to a cost of 3 & traffic is now being distributed evenly.

june03