I don't recall how many connections a browser makes to a singe host but you are right
it's a common thing that is done.
There is more than one product in the market place that uses this 'trick' to try
and accelerate web sites.
For the most part it works.
I would be very interested in any for of investigation around how much of a difference
does this really make and would be willing to participate in such an investigation.
However I think there is also value in understanding what impact a DNS cache hierarchy
within NZ would have for NZ as a whole, I am somewhat of an idealistic person so perhaps
it has no value and it just of interests me.
I would also be interested in understanding what other providers get in terms of cache hit
vs recursion and overall requests vs infrastructure deployed. I know this is somewhat
treasured and possibly not publicly available information.
If there is any interest from other parties to share this I will approach the people here
and see what can be done around some form of disclosure.
Just my thoughts at 6:30 am...
From: nznog-bounces(a)list.waikato.ac.nz [mailto:firstname.lastname@example.org] On Behalf
Of Nathan Ward
Sent: Friday, 21 May 2010 1:49 a.m.
To: NZNOG List
Subject: Re: [nznog] Broadband experience and DNS resolution speeds
On 21/05/2010, at 1:42 AM, Joe Abley wrote:
On 2010-05-20, at 09:22, Nathan Ward wrote:
Who on produced this report? Can they come to the
next NZNOG meeting for a flogging?
There are grains of truth in the idea that increased latency between clients and
resolvers can lead to decreased performance for web applications. Many of the newfangled
URIs and similar techniques deliberately to defeat caching, since caching for some
interactive web $buzzword.$excitement apps leads to user pain and suffering.
Vixie presented some data at the recent DNS-OARC meeting in Prague which described a
trend for decreasing DNS cache hits, and at least in some cases found that random-looking
URIs were contributing to the effect (see
If an application like Facebook can generate a few hundred HTTP sessions per page load,
it seems possible that cache misses (both in DNS and HTTP caches, remote and local) give a
greater effect that you would imagine, and perhaps the cumulative effect of
Dunedin-Auckland DNS latency has some noticeable effect. But I agree it seems like a
stretch (every cache miss in Auckland probably requires a trip to an authority-only server
across an ocean).
It's quite common to use random hostnames to encourage web browsers to parallelize
sessions, as (from memory) most browsers will not open more than 4 connections to a single
Some actual science might be nice to see, maybe.
NZNOG mailing list