[c-nsp] Unintentional load balancing of traffic

[CiscoNSP List]

Thanks Raymond - Ive adjusted the ospf cost on the "backup" link from 202 to 215 on both ends, and now traffic is behaving as wanted....i.e no more load-balancing


Cheers for all the replies.




________________________________________
From: cisco-nsp <cisco-nsp-bounces at puck.nether.net> on behalf of Raymond Burkholder <ray at oneunified.net>
Sent: Friday, 18 September 2015 6:43 PM
To: cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] Unintentional load balancing of traffic

> Link 1 (primary) has ip ospf cost 201
>
> Link 2 (secondary has ip ospf cost 202
>
> But traffic egressing from this PE is load balancing(per session) across
the
> 2 links?
>
> If I do a sh ip route foo, it displays both paths, known via OSPF and
route
> metric of 205?

Hazarding a guess:  you have explicit costs assigned to the local links of
201 and 202.  But as OSPF is a link vector protocol, all costs between local
interface and destination interface are added together.  So when you add the
cost of all links between source and destination, they must add up to 205 on
each of two paths.  And thus get load balanced.


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