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.
:)

[ciscodaze]

your best bet here is cisco documentation, (and google) its a big topic...
CEF, layer 2 link aggregation load balancing, process load balancing, default CEF souce/dest load balancing...

start here http://www.cisco.com/en/US/docs/ios/12_0s/feature/guide/pplb.html

everything you need to know for ccna is in your second sentence.

[ciscodaze]

your best bet here is cisco documentation, (and google) its a big topic...
CEF, layer 2 link aggregation load balancing, process load balancing, default CEF souce/dest load balancing...

start here http://www.cisco.com/en/US/docs/ios/12_0s/feature/guide/pplb.html

everything you need to know for ccna is in your second sentence.

heres is a better link
http://tools.cisco.com/search/JSP/search-results.get?strQueryText=load+balancing&Search+All+cisco.com=cisco.com&language=en&country=US&thissection=f&accessLevel=Guest

[Fuzz]

As far as EIGRP is concerned, the load balancing happens over L3. It does not concern itself with the layer aspects, other than the interface being up/up of course.

To load balance over two WAN links equally, you would have to have two links of the exact same bandwidth and delay (using default K values) to get the same metric and therfore two sucessors, by default. Offset lists and unequal cost load balancing are also possible to influence the amount of routes added to the routing table. These are CCNP topics.