[72195] in North American Network Operators' Group
Re: ultradns reachability
daemon@ATHENA.MIT.EDU (Edward B. Dreger)
Fri Jul 2 01:23:00 2004
Date: Fri, 2 Jul 2004 05:22:20 +0000 (GMT)
From: "Edward B. Dreger" <eddy+public+spam@noc.everquick.net>
To: "Nanog@Merit. Edu" <nanog@merit.edu>
In-Reply-To: <Pine.GSO.4.58.0407020355560.12790@sharpie.argfrp.us.uu.net>
Errors-To: owner-nanog-outgoing@merit.edu
CLM> Date: Fri, 02 Jul 2004 04:18:07 +0000 (GMT)
CLM> From: Christopher L. Morrow
[ editted for brevity -- some punctuation/wording modified ]
CLM> So, I thought of it like this. Rodney/Centergate/UltraDNS
CLM> knows:
[ snip enumeration ]
CLM> [and] should know almost exactly when they have a problem
CLM> they can term 'critical'...
One essentially has a DNS network on top of IP network. Looks
like O(N) with centralized monitoring, although it could approach
O(N^2) if each server/pod cross-monitored all the others.
CLM> The problem then becomes the "Hey, .org is dead!" From where
CLM> is it dead? What pod are you seeing it dead from? Is it
CLM> routing TO the pod from you? FROM the pod to you? The pod
CLM> itself? Stuck/stale routing information somewhere on the
CLM> path(s)? This is very complex, or seems to be to me :(
I find your perception of complexity ironic. Yes, there's a good
deal of splay. However, I suspect a network the size of UU also
has a fair amount of peering splay, with a couple downstreams
thrown in for good measure. ;-)
However, I agree anycast has additional design implications:
* Should servers/pods talk among themselves using mcast along
pairs that follow L3 topology? Should N servers/pods each
communicate with (N / 2 + 1) others, ignoring L3 topology?
Fast poll the former and slow poll the latter?
* If servers/pods communicate among themselves, should they use
unicast addresses? anycast addresses? anycast addresses
tunneled through unicast?
* Each pod a stub? Each pod interconnected with an OOB OAM
network? All pods interconnected with sizable backbone? Does
multicast serve a purpose?
Eddy
--
EverQuick Internet - http://www.everquick.net/
A division of Brotsman & Dreger, Inc. - http://www.brotsman.com/
Bandwidth, consulting, e-commerce, hosting, and network building
Phone: +1 785 865 5885 Lawrence and [inter]national
Phone: +1 316 794 8922 Wichita
_________________________________________________________________
DO NOT send mail to the following addresses:
davidc@brics.com -*- jfconmaapaq@intc.net -*- sam@everquick.net
Sending mail to spambait addresses is a great way to get blocked.
