From owner-freebsd-chat Tue Jan 29 13:42:30 2002 Delivered-To: freebsd-chat@freebsd.org Received: from riker.skynet.be (riker.skynet.be [195.238.3.132]) by hub.freebsd.org (Postfix) with ESMTP id 5C1CC37B435 for ; Tue, 29 Jan 2002 13:41:42 -0800 (PST) Received: from [10.0.1.21] (ip-27.shub-internet.org [194.78.144.27] (may be forged)) by riker.skynet.be (8.11.6/8.11.6/Skynet-OUT-2.16) with ESMTP id g0TLfG503363; Tue, 29 Jan 2002 22:41:16 +0100 (MET) (envelope-from ) Mime-Version: 1.0 X-Sender: bs663385@pop.skynet.be Message-Id: In-Reply-To: References: X-Grok: +++ath X-WebTV-Stationery: Standard; BGColor=black; TextColor=black Reply-By: Wed, 1 Jan 1984 12:34:56 +0100 X-Message-Flag: Outlook : A program to spread viri via e-mail. Get yourself a real mail client -- try Eudora (http://www.eudora.com/), mutt (http://www.mutt.org/), or pine (http://www.washington.edu/pine/). But please, get something other than Outlook. Date: Tue, 29 Jan 2002 22:39:15 +0100 To: "Jeremy C. Reed" , freebsd-chat@freebsd.org From: Brad Knowles Subject: Re: serving content from the closest server Content-Type: text/plain; charset="us-ascii" ; format="flowed" Sender: owner-freebsd-chat@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org begin C:\WINDOWS\I-COULD-HAVE-WIPED-OUT-WIN.INI At 12:57 PM -0800 2002/01/29, Jeremy C. Reed wrote: > What are some methods that content delivery services use for serving from > an access point closest to the end user? Well, there's the Akamai solution -- have the content provider use an Akamai-specific URL, which points at an Akamai server. When the URL is accessed, proprietary algorithms are used by Akamai to determine the geographic and topological location of the user, and the "nearest" Akamai server, at which point a redirect is issued to that local server. When the request hits the local server, it serves up the content from its local cache, or pulls the content from the private source location and and then caches this as well as passing it on to the requester. Obviously, this requires a lot of proprietary work, and you have to "Akamaize" your site in order to be able to take advantage of their content distribution/caching network. > Are there DNS servers that count the number of hops between the end user > and the possible webservers, and then reply back with an address that is > closest? > > Or maybe figure out the fastest? There is the cisco Global Director solution, but I don't know how it works, or how it determines how loaded a server is, etc.... You end up having to greatly reduce the TTL on the DNS responses, in order to deal with the problem of servers going down, becoming unreachable, getting overloaded, etc.... This causes its own load problems. You do end up needing to have a proper L4 load-balancing switch (or set of them) to handle the load at each site, and then some sort of higher-level solution to distribute load across the sites. RadWARE has a different kind of solution for their load-balancing switches. > Or are there web servers (or a CGI or Apache module) that count the number > of hops (or the amount of time) between it and the client -- and then > either send a HTTP redirect or modify the HTML image or href links to > point to a closer server? I'm not aware of anything, no. -- Brad Knowles, Do you hate Microsoft? Do you hate Outlook? Then visit the Anti-Outlook page at and see how much fun you can have. end To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message