RE: [dnsop] Re: Root Anycast (fwd)

"Joe Shen" <> Thu, 30 September 2004 17:06 UTC

Received: from ( []) by (8.9.1a/8.9.1a) with ESMTP id NAA10467; Thu, 30 Sep 2004 13:06:10 -0400 (EDT)
Received: from ([]) by with esmtp (Exim 4.33) id 1CD4Vm-0005Jx-3J; Thu, 30 Sep 2004 13:14:47 -0400
Received: from localhost.localdomain ([] by with esmtp (Exim 4.32) id 1CD4BG-0003ju-Qk; Thu, 30 Sep 2004 12:53:22 -0400
Received: from ([] by with esmtp (Exim 4.32) id 1CCpo6-00029O-HV for; Wed, 29 Sep 2004 21:32:30 -0400
Received: from ( []) by (8.9.1a/8.9.1a) with ESMTP id VAA11819 for <>; Wed, 29 Sep 2004 21:32:27 -0400 (EDT)
Received: from [] ( by with smtp (Exim 4.33) id 1CCpvx-0000c7-W6 for; Wed, 29 Sep 2004 21:40:55 -0400
Received: (qmail 16127 invoked from network); 30 Sep 2004 09:20:41 +0800
Received: from unknown (HELO topgun) ( by with SMTP; 30 Sep 2004 09:20:41 +0800
From: Joe Shen <>
To: 'Dean Anderson' <>,
Date: Thu, 30 Sep 2004 09:33:42 +0800
Message-ID: <000001c4a68d$85bd6d00$6f02a8c0@topgun>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
X-Priority: 3 (Normal)
X-MSMail-Priority: Normal
X-Mailer: Microsoft Outlook, Build 10.0.2627
Importance: Normal
In-Reply-To: <>
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1441
X-Spam-Score: 0.0 (/)
X-Scan-Signature: 9a2be21919e71dc6faef12b370c4ecf5
Content-Transfer-Encoding: 7bit
X-Mailman-Approved-At: Thu, 30 Sep 2004 12:53:13 -0400
Subject: RE: [dnsop] Re: Root Anycast (fwd)
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: IETF-Discussion <>
List-Unsubscribe: <>, <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-Spam-Score: 0.0 (/)
X-Scan-Signature: 7fa173a723009a6ca8ce575a65a5d813
Content-Transfer-Encoding: 7bit

Would you please give more about  the problem of  anycast with root
server ? 

To my understanding, Per-Packet Load Balancing  works only in situation
all  DNS servers installed
behind the same router, and it  CAN NOT guarantee sequencing of TCP

The first problem of PPLB  is ,  it could not be implemented  for a
server farm which distributes across 
internet, and  the only thing it does is  replacing traditional  load
balancer  with router. 

I don't know whether there is some research in  "how many packets does
one DNS request cost " and "how
many TCP traffic occupies in DNS traffic".  If  most of DNS request cost
more than one UDP packets, out-of-sequence 
may be a problem. Also , if TCP occupies more than 10% of traffic it
will also be a problem. 

The third,  ECMP in current  DNS server farm guarantees both per-packet
load balancing in UDP traffic and per-flow distribution
in TCP traffic.  Considering distributing DNS server across multiple AS,
I think the advange is obvious than PPLB.

Joe Shen

ps.  where can I find detailed information on Root server GTLD server
configuration  ( hardware , software, and network infrastructure)?
        I just know they use anycast but how they choose system

-----Original Message-----
[] On Behalf Of Dean Anderson
Sent: Thursday, September 30, 2004 5:41 AM
Subject: [dnsop] Re: Root Anycast (fwd)

Some time back we were talking about anycast being a bad thing on DNS
Root servers. It was suggested by that conversations typically take only
one path as a result of CEF-like caching.  I noted that providers were
working on per packet load balancing. Well, here it is, in the "major

Per-Packet Load Balancing

So, it seems that we need to review whether the use of anycast on the
root nameservers is a good idea. I suggest that we ignore for the
momeent anyway the question of whether the deployment of anycast was
done with adequate technical analysis, discussion, and approval, and
just consider whether we should continue doing it.  However, the Root
server operation and oversight issues are very important should also be
discussed, too, but probably by different forums.


---------- Forwarded message ----------
Date: Tue, 18 May 2004 19:03:52 -0400 (EDT)
From: Dean Anderson <>
To: Paul Vixie <>
Subject: Re: Root Anycast

On 18 May 2004, Paul Vixie wrote:

> Careful design by whom?  Organic compared to what?  I assure you that 
> f-root has grown by careful design.  It's only organic in that we go 
> where we're invited rather than having a gigantic budget that could be

> used as a leash.

Do you mean "Careful Design" like the non-standard changes in Bind 9
AXFR and IXFR?  I don't think we can take too much of that sort of thing
in the operation of the root servers before we have serious problems.

Unilateral action is not a good thing. There is no point in having an
IETF (Remember the "Internet __Engineering__ Task Force" in IETF) if you
just implement whatever you think OK at the moment (AXFR mods, IXFR
mods, Anycast, and probably more that we just don't yet know about)


Av8 Internet   Prepared to pay a premium for better service?         faster, more reliable, better service
617 344 9000

dnsop resources:_____________________________________________________
web user interface:
mhonarc archive:

Ietf mailing list