Fundamental questions of backbone design

Fri Oct 18 18:03:16 UTC 2013

Hello everyone

I have some fundamental questions about backbone design. Feel free to point
me to any discussions/presentation material related to these questions.

   1. As I understand it's (sort off) common practice to give highest
   localpref to customer routes then peering and finally transit. Does this
   works well or you see issues with people who have 10+ prepends on some
   peering routes calling you to not send traffic via those circuits? Does it
   makes sense to put a rule to avoid routes 2-3 AS path away when changing
   local preference?

   2. If I have more peering capacity and relatively less capacity between
   my own PoPs and I start injecting routes in my IGP then how to prevent
   change of choking of backbone? Is it standard practice to have more
   capacity on backbone then peering links? Or I have to inject less routes in
   IGP - say a few % of total routes?

   3. How can I maintain use of routes I am learning from various other
   networks (transit+peers+customer) across my IGP? Is BGP community tagging
   good way out?

   4. How is iBGP Vs OSPF for IGP? I keep on hearing that OSPF is good &
   lot more faster in changing routes during a breakdown as compared to slow
   hold time based iBGP session. Is there's more clear comparison of
   limitations of both when designing?

Appreciate your time & help.

Thanks.

-- 

Anurag Bhatia
anuragbhatia.com

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