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New Member

Load Balancing


Im trying to do a load balance of the traffic going out of my LAN.

I've got 2 L3 LAN switches which is connected directly to each WAN router which have equal path cost towards the MPLS cloud.I'm running ospf on the interfaces that connects the LAN switches and the WAN router. My question is that when the packets going out reach each L3 LAN switches, it will not see equal path cost going out as advertise by both WAN routers. I tried to mingle with the metric values but couldnt get my ideal solution. Could someone advise me on how to achieve load balance on this? Thanks.


Re: Load Balancing

hi phhee...

will you clear the connectivity between your switchs and wan router... how they are connected with each other... and what you exectly want..?




Re: Load Balancing

if you cannot get ospf to load balance, then there is clearly a cost/ad issue at hand or the specific type of load balancing you want is not enabled.

equal cost & AD paths are load balanced with ospf automatically. if you need to force the cost of an interface, use the 'ip ospf cost' command in interfaceConfig mode.

for process-switching: load balancing is per-packet (no ip route-cache)

for fast-switching: load balancing is per-destination (ip route-cache)

also, do a 'show ip route' and look for the destination route(s). there should be two and the one that has an asterisk (*), next to it is the active route for the next packet (perPacket) or destination-based flow (perDestination).

provide some 'show ip route' and 'show config' output if you can.

New Member

Re: Load Balancing


New Member

Re: Load Balancing


I've attach a simple diagram to clarify my doubts.

What i wish to achieve is that:

- When packets going out towards WAN arrived at LAN Sw 1 or 2, it will see that there are 2 equal paths going out vias WAN router 1 or 2

- However the metric value would be different as seen from each LAN switch thus not able to achieve what i want

-Tried to adjust the metric value but couldnt get an ideal solution.

Additional info:

-All the interface are running ospf and within the same area.

Hope this is clearer. Thanks!