nanog mailing list archives

Re: Scalability issues in the Internet routing system


From: "Alexei Roudnev" <alex () relcom net>
Date: Thu, 27 Oct 2005 10:15:04 -0700


If this 500K routes come from upstream, it is just _default_ so can be
installed instantly if configuration is correct.

If this 500K routes are from the peer, you switch (in reality) 10 - 20%, so
it is simpler anyway.

Even if it is multihome customer, there is not any need in _fast_
installation for these 500K routes. You just switch from one
provider to another _some_ of the routes - if it takes 1 minute, nothing
wrong happen.

Then, calculate:
500K routes, say 32 bytes/route (if not compressed by some way), 16MB.
T1 link, 100K/second, 160 seconds, 3 minutes.
100Mbit link, 10MB/second, 2 seconds.

T1 wil not be suitable for full routing of course, so what?

Just agaion - there are many tricks todo things right, out of theoretics of
IPv6 commitees.

----- Original Message ----- 
From: "Blaine Christian" <blaine () blaines net>
To: "Lincoln Dale" <ltd () interlink com au>
Cc: "Alexei Roudnev" <alex () relcom net>; <nanog () nanog org>; "Daniel Senie"
<dts () senie com>
Sent: Wednesday, October 26, 2005 6:06 PM
Subject: Re: Scalability issues in the Internet routing system



there have been public demonstrations of released routers
supporting upwards of 1.5M IPv4+IPv6 prefixes and demonstrations on
routing churn convergence time. <http://www.lightreading.com/
document.asp?doc_id=63606> contains one such public test.


The http://www.lightreading.com/document.asp?
site=testing&doc_id=63606&page_number=6 part may be a bit
misleading.  For me it would be more interesting to see what happens
when 500k routes completely disappear from the router then come
back.   I want to see a 500k route push from a neighboring CRS in
that amount of time...

Of course the routes can switch quick when you use a layer of
indirection (folks have been doing that for a few years now).  My
question is how fast can you install routes from a standing start (or
a 1/4 of a standing start if this is 2M prefixes).

I will leave the question on whether it is actually worth an
investment in time and resources as an exercise for the reader <grin>.

Lightreading people,  test it like that!  It will be much more
entertaining and perhaps even a bit enlightening to see how major
vendors compare on "brand new" route installation into RIB and FIB.
They only have to twiddle a couple bits to make indirection work
quickly.  Having to deal with a brand new prefix is a completely
different problem.










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