EIGRP Metrics

[ccie5851]

Does anyone have a good link that discusses the intervals that EIGRP checks the loading and delay metrics on a link to calculate the best path through a network?

If for example, we have 2 links with equal cost load balancing, will EIGRP "see" the delay or loading on one of the links and route traffic over the other link? If so, how often is this information communicated between the EIGRP neighbors?

Thanks!

[KONSTANTIN FEDOROV]

Hello.

Yes this is very interesting question, some time ago I want find info about this , but

cannot find any links. I made experiment, and find that event for update only

disappear route or up/down link.

[wukunpeng]

eigrp equal cost load balancing use round robin.

The metric message is included hello packet,neighbors say hello every few seconds,just like ptp or nbma network,

[ssymonds]

By default only the bandwidth and delay metrics are usd by eigrp to calculate the metric.

delay being cumulative of all interface delays along the ip route's path, bandwidth being reported as the 'smallest' bandwidth in the path.

plse see the folowing url for more details:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121cgcr/ip_r/iprprt2/1rdeigrp.htm#xtocid1895715

http://www.cisco.com/warp/public/103/eigrp1.html#5

Load balancing across equal paths is also influenced by the switching mode:

- process switching = round-robin per-packet

- fast-switching = round-robing per destination prefix

- cef = (configurable) round-robin per-packet or per-session based on (source/dest hash)

http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121cgcr/switch_c/index.htm

thx

steve