Load sharing over different speed lines

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Nov 7th, 2009
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I have three 2mb serial link and one 6mb Ethernet link for the destination and am using OSPF.how i can configure load sharing to use all links.

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paolo bevilacqua Sat, 11/07/2009 - 11:06
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In short, you cannot.

Either use slower circuit as backup only, or send some traffic statically configured into it.

Joseph W. Doherty Sat, 11/07/2009 - 15:48
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OSPF only supports equal cost multiplath routing. You could configure the cost on all links the same, this however would (statically) not send the correct proportion of traffic to the Ethernet link.

If the three 2 Mbps links were (MLPPP) bonded, then you could equaly split the traffic between it and the Ethernet link.

More complex approaches include: define 3 GRE tunnels across the Ethernet link, and equally route across them and the serial links. Or, if your equipment supports PfR with the PIRO feature, it could dynamically load balance across the different links. (You could also dynamically load balance using an earlier version of OER/PfR using statics which you might need to redistribute into OSPF).

paolo bevilacqua Sat, 11/07/2009 - 19:21
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I did not noticed there are three serial links, not just one.

So yes, put them in mlppp first and you're done.


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