Load-balancing with 'variance' command?

[jeanie.embry]

In an attempt to load-balance a large corporate internetwork consisting of hybrid, frame relay & pt-pt T1 lease lines .. running EIGRP on backbone with static routes to remote stub networks.. turning up 'variance' on the backbone network led to problems with convergence. What design issues should be considered? Should the static routes be re-distributed? (All nets currently in same AS..)

[ruwhite]

Can you explain what sorts of convergence problems you were seeing when you configured variance? There shouldn't be any impact on convergence, since we aren't changing the number or types of routes being advertised through the network, or the query ranges on routes, etc.

:-)

Russ.W

[jeanie.embry]

The static route entries wouldn't be the problem?? Static routes progagated even though not learned from EIGRP ?? (I seem to recall the problem equated to path selection back to remote, stub networks.)

[kkalaycioglu]

Two most important factors about EIGRP scalability (and therefore conv.time) are route summarization (auto and manual) and limiting EIGRP queries. Supposing that you've problems with EIGRP queries, you would see EIGRP SIA (Stuck-In-Active) syslog messages (Do you see?). If you don't I think you've not in trouble with queries. When it comes to summarization, it's generally an issue of mid-size to large internetworks and can significantly affect route table size, routing traffic and so convergence time. If you don't have too many routing table entries this is not a matter for you also. At last some flapping routes (probably because of flapping links) can be source of excessive updates/queries/replies. You can maonitor this issue. But anyway it's better you'd explain your convergence issues.

Best Regards.

[jeanie.embry]

I suspect problem/s encountered due to too many routing table entries and too many alternate routes... although specific data not available. Perhaps an exterior routing protocol needs to be considered?

[ruwhite]

Statics will on' be propagated through EIGRP if you are redistributing them. Again, can you explain what scaling issues you're seeing, SIAs, etc?

Russ.W