[98384] in North American Network Operators' Group
Re: Content Delivery Networks
daemon@ATHENA.MIT.EDU (Patrick W. Gilmore)
Tue Aug 7 09:09:16 2007
In-Reply-To: <008101c7d8cb$74bef1e0$6701a8c0@w2lan.cesnet.cz>
Cc: "Patrick W. Gilmore" <patrick@ianai.net>
From: "Patrick W. Gilmore" <patrick@ianai.net>
Date: Tue, 7 Aug 2007 09:07:28 -0400
To: nanog@merit.edu
Errors-To: owner-nanog@merit.edu
On Aug 7, 2007, at 3:59 AM, Michal Krsek wrote:
> 5) User redirection
> - You have to implement a scalable mechanisms that redirects users
> to the closes POP. You can use application redirect (fast, but not
> so much scalable), DNS redirect (scalable, but not so fast) or
> anycasting (this needs cooperation with ISP).
What is slow about handing back different answers to the same query
via DNS, especially when they are pre-calculated? Seems very fast to
me.
Application redirection is far, far slower. (I am assuming you are
talking about something like HTTP level redirects. Did you mean
something else?)
As for anycast, with your own backbone, you don't need any
cooperation. Even if you don't, the cooperation you need from your
providers & peers is minimal at worst. (At least relative to writing
the code for, say, DNS redirection.) But anycast assumes "BGP knows
best", and we all know that is not even close to the truth.
--
TTFN,
patrick
