Subject: Re: Anycast root metrics and analysis

From: [email-masked]
Date: Fri, 3 Nov 2000 11:37:29 -0800 (PST)

> On the "anyone can run their own server"  .. with the anycast scheme
> they can't really be stopped, and other than by filters in other providers
> access lists, they can't really be prevented from offering transit either
> should they want to.   

It is somewhat easier to get those filters in place and keep them in
place if a single AS should be the known transit provider.  It would
need to get added to the "bogon" filter lists out there (which have
things like how to deal wtih RFC 1918 addresses and exchange point
addresses in them now), but that's not all that hard.  A well behaved
participant would also have it in their filters for outbound
announcements.

But there's more to the stability of the DNS system
> than just getting the answers back as quickly as possible - the database
> needs to be properly maintained and updated.   What's more the comparative
> stability of the root zone actually makes that harder (it is easy to set up
> and test update procedures for a database that changes every day, much
> harder for one that only changes once a year or so).  More servers spread
> around improves access, but decreases trustworthiness of the data.  The
> two need to be balanced.

This is very true.  Like you, I wonder if "everyone" maintained a copy
of the root how well propogation of updates would occur.  My current
take is that splitting things with a "local copy permitted but single
global announcement" scheme would limit the scope of errors to those
making them, which has some advantages.

> 
> kre
> 
> ps: where I am now I am getting 1.8second RTTs to home (at least 1.2s to
> any root server) and approx 30% packet loss ... I know what benefits there
> are to be obtained from this.
> 
> 
>

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From: Harald Alvestrand <[email-masked]>
Date: Fri, 03 Nov 2000 22:45:27 +0100

If read as a physically single point, the single global announcement idea 
kills any hope of the anycast scheme benefiting users in smaller ISPs 
outside the US.

I still think an anycast AS number needs to be centrally owned and 
administered, with monitoring of the global routing tables to detect bogon 
announcements, just like a real, normally internally-connected AS would behave.

We might agree.
(and - I think the Right Thing is a Root Server Consortium operating under 
ICANN contract, with responsibility for ONE of the addresses, at least at 
first, with the rest of the root server set being managed exactly the way 
it is today. but we are getting VERY far into politics rather than technology).

--
Harald Tveit Alvestrand, [email-masked]
+47 41 44 29 94
Personal email: [email-masked]

---

From: [email-masked]
Date: Fri, 3 Nov 2000 14:18:33 -0800 (PST)

> kills any hope of the anycast scheme benefiting users in smaller ISPs 

The single global announcement doesn't have to mean a single physical
presence; it could be combined with the anycast hack described in my
draft to distribute the servers around the global announcer's
topology.  Frankly, though, I would not combine the two.  Given that
there are multiple root servers, I would rather suggest doing one with
one root server and the other with a different root server.  That
strategy could mean, however, that the ISPs not running their own copy
would be dependent for good performance on a connection to some entity
large enough to have a network presence pretty much everywhere.  That
tends to mean fee-based traffic exchange.

> it is today. but we are getting VERY far into politics rather than technology).

A centrally administered anycast AS has a much better chance of
imitating the working of an internally-connected AS than Masataka's
current proposal or the compromise I suggested.  Depending on the
implementation, it might not look very different from those multihomed
enterprises that announce their address space via BGP and that do
internal connections via VPNs.

Getting that to work in a root server consortium though does push us into
the politics of how does get approval to join, blah, blah, blah.

				regards,	
					Ted Hardie