best practice for advertising peering fabric routes

Dobbins, Roland rdobbins at
Wed Jan 15 14:49:10 UTC 2014

On Jan 15, 2014, at 9:18 PM, Leo Bicknell <bicknell at> wrote:

> However, a good engineer would know there are drawbacks to next-hop-self, in particular it slows convergence in a number of situations.  There are networks where fast convergence is more important than route scaling, and thus the traditional design of BGP next-hops being edge interfaces, and edge interfaces in the IGP performs better.

A good engineer also knows that there are huge drawbacks to having a peer's network infrastructure DDoSed, routes flapping, core bandwidth consumed by tens and hundreds of gb/sec of attack traffic, et. al., too.


> By attempting to force IX participants to not put the route in IGP, those IX participants are collectively deciding on a slower converging network for everyone.  I don't like a world where connecting to an exchange point forces a particular network design on participants.

Concur.  But that's the world we live in, unfortunately.

It's just another example of the huge, concentric nature of the collateral damage arising from DDoS attacks, both from the attacks themselves, and from the compromises folks have to make in order to increase resilience against such attacks.

> That's some circular reasoning.

Not really.  What I'm saying is that since PMTU-D is already broken on so many endpoint networks - i.e., where traffic originates and where it terminates - that any issues arising from PMTU-D irregularities in IXP networks are trivial by comparison.

Roland Dobbins <rdobbins at> // <>

	  Luck is the residue of opportunity and design.

		       -- John Milton

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