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Date: Mon, 25 Mar 2002 18:24:28 -1000
Subject: Re: relative vs absolute URL's /  CPU processing overhead
From: Sivakatirswami <katir@hindu.org>
To: <users@httpd.apache.org>
Message-ID: <B8C51BDC.9A04%katir@hindu.org>
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on 3/25/02 5:30 PM, James Harr at james@grickle.org wrote:

> When a web browser requests a url, it does shoot the DNS server for a
> domain. Netscape 3.x-4.x, however, has its own built in dns server, which
> is an other story..
> 
> The ISP keeps a cache of these names (if they don't, they should be). When
> you request for an IP of foobar.com, and it has 5 different round robin
> addy's, the cache servers keep these in record too. So they round robin
> each
> 
> Let me knwo if this is what you wanted,
> Later,
> jh
Thanks, James, this is very instructive but I think you may be a bit over my
head...

> the question remains, is there a speed
>> difference between a relative URL vs an absolute one? Albeit perhaps
>> trivial in certain configurations...but not trivial if there is
>> congestion on packet transfers to the IP/server doing the DNS...?
 
scenario: client web browser in San Diego find ones of our pages on
google...www.hinduismtoday.com, then clicks on that link...  then a DNS
server, closest one, say at ISP: electricity.com (the IPS for the client
logging onto the net) does the resolution and the IP for our domain is sent
back to the client browser, that being 64.75.176.66 for a virtual domain
hosted at ISP-Web Host: mahiai.aloha.net in Honolulu. The client browser
then opens a socket to that IP and sends an HTTP GET request for foo.html...
now, if that document contains 20 img refs that are absolute

<img src= "http://www.hinduismtoday.com/images/header.gif"

then will the web browser "shoot" for DNS 20 times to it's own ISP:
electricity.com for each image?

If I hear you right you are saying, no... the ISP-web host that is serving
the page foo.html should have a cache of DNS? and also that possibly the web
client itself (more recent browsers) is caching the DNS? i.e the web client
is NOT shooting for DNS to any DNS server after the first one is resolved
and therefore speed issues for absolute or relative links for images in an
*html pages are insignificant/trivial as you said initially.. .Did I get
that right? 
Hinduism Today

Sivakatirswami
Editor's Assistant/Production Manager
katir@hindu.org 
www.HinduismToday.com, www.HimalayanAcademy.com,
www.Gurudeva.org, www.hindu.org

Read The Master Course Lesson of the Day at
http://www.gurudeva.org/lesson.shtml


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