Load Balancing with EIGRP

[alabedekenny]

Hi all,

I seem to be confused about the above topic.

I know that EIGRP can load balance over four equal cost paths (bu default), and six paths (configured). Also, one can manipulate the metrics so that all routes can have equal paths.

BUT... the question is this: does the load balancing happen at Layer 2 or Layer 3? What is the difference between per-packet load balancing and per-destination load balancing?

How best can one implement an effective load balancing with EIGRP over two WAN links from a remote location to the central office.

Thanks for your contributions.

[cadet alain]

Hi,

the load balancing happens at layer 3 and is dependent of the switching process:

-if it is CEF( default): the packets are load balanced per flow

-if it is fast switching: the packets are balanced per destination

-if it is process switching: packets are load balanced per packet

In CEF you can change the load balancing behaviour with the interface command: ip  load-sharing per-packet

Now about the differences:

-per destination: each destination IP will be forwarded on a different link

-per packet: each packet goes on a different link

-per flow: each src ip dst ip pair is gonna take a different path( this is a rough explanation but that is the big picture)

Regards.

Alain