[c-nsp] MPLS best practices question

[cisconsp at SecureObscure.com]

Good morning everyone,

 

If I may have a moment of your time, I'm approaching a small MPLS deployment
(L3 VPN functionality only, no TE or L2VPN) on existing infrastructure
primarily 6500's & ASR1k's and would very much like the opinion of the list
on some best practices. There are several technologies that I'm trying to
determine the appropriateness to activate or tune and I'm scared to blindly
enable them without a good reason to do so as I haven't seen some of them
used in a production environment before.

 

1)       IGP LDP Sync. I am really looking for some direction as to where it
makes sense or not to use. The same is also true for the IGP LDP startup
delay timers. 

 

2)       OSPF timers or BFD? Currently my approach has been ospf timers of
1/4, its fast and seems pretty compatible with everything I have tried it
on. All of my links are direct between routed ports so there are no
intermediate devices that would keep a link lit after equipment failure. I
know BFD makes sense but some of my code is old and linecards are flakey so
I'm curious to know who has ditched low timers for BFD or vice versa. 

 

3)       OSPF costing, automatic bandwidth-based or manual costing of PE-P
and P-P links? I have seen both used in production before, I do have 10gig
interfaces and 40gig port-channels so I would need to alter the ospf
reference bandwidth if auto-costing.

 

4)       MTU on p2p gigabit ethernet links. Currently I have stolen another
list members MTU settings using 1530 for global & mpls MTU, and 1524 as IP
MTU on all PE-P and P-P interfaces. I don't have any jumbo frame
requirements, but do have upstream providers that may not support jumbo so
I'm trying to keep the MTU fairly low.

 

5)       Other knobs and tweeks? I'm usually a minimalist, I go forward with
the default settings and test, then alter as little as I need to meet any
special needs. With that in mind, I do expect to find things that are
necessary to modify but really would like to see wide adoption or clear
requirements in doing so.

 

Thank you for your time, please feel free to share anything off list if you
don't want to disclose it to the general public. I really value the opinions
that list members have provided thus far,

 

John