OSPF Costs Formula that include delay.

Sat Jan 25 17:12:10 UTC 2014

On Friday, January 24, 2014 10:59:19 PM Owen DeLong wrote:

> I wasn’t attempting to promote or discourage use of MPLS.
> I was merely endeavoring to point out that in an MPLS
> world, OSPF costs are not how you want to manage your
> traffic.

Again, only an issue when using RSVP-TE.

I'd recommend MPLS-TE (especially core-to-core, as that is 
more scalable) when looking at making more aggregate routing 
decisions when dealing with a bandwidth vs. latency 
conundrum.

Adjusting IGP costs in favour of latency works well, but can 
have pile-on effects behind or in front of the links being 
worked on, which can be confusing to troubleshoot when 
taking other PoP-specific factors into account. It also 
obliterates any sane cost-assignment mechanism you might 
have developed (or at best, makes it overly complex).

There is room for both options, typically depending on 
network size, number of links, rate of topology change in 
your network and skill level of your network engineering 
team.

Mark.
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