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Re: Verio Peering Question
From: "Patrick W. Gilmore" <patrick () ianai net>
Date: Thu, 27 Sep 2001 15:46:19 -0400


At 07:15 PM 9/27/2001 +0000, P R wrote:
>
>I have a quick question about Verio's public peering policy.  What is the
>smallest size prefix that Verio will accept from public peering?  The reason
>why I ask is because my company informed me that Verio will not accept
>anything from a Class A address with a prefix smaller than a /20 from pubic
>peering.  Is that true? If so, how do small ISP's work around this?

The same way they did when Sprint filtered.

If you have less than a /20, you are getting IP space from one of your upstreams. The upstream announces the larger CIDR, Verio hears it, and sends the traffic there. This happens even if it would be "better" for Verio to send it to your other upstream.

People have argued that this hurts performance on Verio's network. It also eliminates the smaller ISP's ability to control traffic flows. (e.g. You have a T1 to Provider-A, who gives you space, and you prepend heavily; you have a DS3 to Provider-B, and do not prepend. Verio will send the traffic to Provider-A.)

Randy (now at AT&T, I believe) and others claim this does not hurt performance and that it is bad to accept small announcements. Arguments include points like the routers cannot handle that many announcements, smaller providers flap more, etc., etc.

Of course, networks much larger than Verio (e.g. UUNET) accept /32s from their customers, as well as send and accept as small as /24s from peers. No other network seems to have a problem with the extra announcements. Verio cannot explain why these larger networks can accept small announcements and still run a network as well (or better) than Verio, but Verio insists networks should not accept small announcements.

One can make one's own judgement what this says about Verio's ability to run a network.


Oh, one other point - Verio accepts smaller announcements from their customers - and propagates them. I guess Verio agrees that other people can run networks with all the extra announcements, even if Verio themselves cannot.


Personally, I think everyone should filter on /20s and longer - but ONLY FROM VERIO. (I suggested this same things when Sprint was applying ACL 112.) Wonder how long Verio would continue to filter if even a few major networks filtered Verio's announcements.


In the end, though, it does not really matter. As long as you have the larger CIDR being announced by someone, you will get the traffic in all but the most unusual circumstances. (I can think of some, but they really are not "normal".) You may have poor performance from Verio, but that might happen anyway....


>Peter Rohrman

--
TTFN,
patrick


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