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New Member

Load balancing in EIGRP

Came across this statement:

EIGRP automatically load balances across links of equal costs. Whether the traffic is sent on a per-destination or round-robin basis depends on the internal switching within the router.

Could somebody let me know which fashion would be specific to which models/series of Cisco routers? Thanks

5 REPLIES

Re: Load balancing in EIGRP

Hi,

Fast-switching is the default (per destination). (ip route-cache command)

You can disable per-destination and do process-switched (per packet; hits CPU) by doing 'no ip route-cache' on the interface.

CEF is the recommended method to use nowadays. You enable it globally with 'ip cef' and by default it does per-destination. you can configure CEF to do per-packet with 'ip load-sharing per-packet' on the interface.

IOS will equal cost route across 4 paths by default. This can be increased to a max of 6 however. With EIGRP you can use the variance command to do unequal load balancing across multiple paths.

New Member

Re: Load balancing in EIGRP

Thanks for your response. A follow up question. Does the destination router have to have the same configuration? If not, how does the destination router know in what order the received packets should be reordered?. Sequence numbers? Thanks.

New Member

Re: Load balancing in EIGRP

Regarding your follow up question, the destination router works according to its configuration. But its better you have same configuration (like CEF) on all your routers, this helps in case you are running VoIP or Video applications.

Re: Load balancing in EIGRP

The destination host puts the packets back together in the right order if they happen to be out of order. The router doesn't do this ... unless the destination is the router. .

New Member

Re: Load balancing in EIGRP

Thanks for the information.

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