BGP Route Reflector - Route Server, Router, etc

Fri Jan 13 22:12:42 UTC 2017

Thanks for all of the replies (on and off list). It is appreciated.

Scaling in this context is simply adding more and more routers and needing/wanting to avoid configuring full mesh iBGP due to the administrative burden of maintaining the growing size of full mesh topology. In one particular network in question, I have 11 routers fully meshed and need to add several more over the coming 6-12 months, possibly adding as many as 10 more routers in that time span. I'd prefer not to continue doing full mesh.

As for 7206VXR with NPE-G1 or G2 cards, we have many sitting in a decommissioned state on shelves as well as a few still alive serving a handful of T-1 lines and various other legacy connections of that sort. These little 7200's sit and run, forever near as I can tell. As many routers in this network do contain full route eBGP connections I will strongly consider your suggestion of avoiding using the 7200's due to potential memory constraints and CPU/convergence time capabilities. I don't think I have done any full table feeds on a 7200 in many years (days of 200k-300k table size days)

This fits in with the kind of feedback I was hoping for, Thanks!

________________________________________
From: NANOG [nanog-bounces at nanog.org] on behalf of Leo Bicknell [bicknell at ufp.org]
Sent: Friday, January 13, 2017 7:23 AM
To: nanog at nanog.org
Subject: Re: BGP Route Reflector - Route Server, Router, etc

In a message written on Thu, Jan 12, 2017 at 08:32:44PM +0000, Justin Krejci wrote:
> I am working on some network designs and am adding some additional routers to a BGP network. I'd like to build a plan of changing all of the existing routers over from full iBGP mesh to something more scalable (ie route reflection).

You might want to better define "scalable".  I don't know your
background or network so I can't guess.  I can say I've seen
the inner workings of some large ISP networks with a lot of hosts
in iBGP that work fine, and then people with 5 routers try and
tell me they have a scaling problem.

What is your actual problem?  Memory usage?  Convergence time?
Configuring the sessions?  Staff understanding of how it works?

> I am wondering if people can point me in the direction to some good resource material on how to select a good BGP route reflector design. Should I just dust off some 7206VXR routers to act as route reflectors?

This is a red flag to me, relative to the questions above.

The 7206VXR, even with an NPE-G2, is a 1.5Ghz Power PC with a paltry
2GB of DRAM.  It was not speedy when new, being roughly equivilent
to the PowerPC G4 processors in Apple Laptops at the time.  It is
approximately 8 times slower than a current iPhone.  Seriously.

If convergence time is anything you care about, a 7206VXR is a very
bad choice.  It may also run out of memory if you have a lot of
edges with full tables.

So what's the actual "scaling" problem?

--
Leo Bicknell - bicknell at ufp.org
PGP keys at http://www.ufp.org/~bicknell/