Message-Id: <m0pw7xe-0004IXC@inca.gate.net>
Date: Wed, 27 Apr 94 07:39 EDT
To: uri@bunyip.com
From: hoymand@gate.net (Dirk Herr-Hoyman)
Subject: Selecting URL from "equal" sites
We've been chatting a bit about what might go in a URC to allow for URL
selection. There's one case we haven't dealt with and it's one that's in
front of us right way. How can you choose between "equal" sites? For
example, how does one pick an archie server or GNN server?
The "correct" URL in this case would be "closest" to me. Close could be
hops or response time or some other metric. This is a tough nut to crack,
but without it, we are likely to beat up on one server or pick a bad one.
There are 2 cases of equal servers that I am seeing:
1. Geographically/network. distributed.
2. Local load sharing.
This first case is like archie servers, the 2nd might be multiple systems @
NSCA for their WWW home page.
I don't see that there's anything a publisher could put in the URC that
would help for #1. Knowing the physical location doesn't always work. Top
level domainnames are not always close. The only thing I see working, in
my understanding of TCP/IP, would be to probe the net ala traceroute. But,
that might really slow the resolution down (imagine probing ALL the archie
servers when the link to australia is slow). The URC server could maintain
a table of response times, but that doesn't necessarily apply to the
client's route.
For #2, the URC server could perhaps randomly order the URLs in the UYRC,
presuming that the 1st one will be chosen. I guess this is the fallback
strategy for #1, where the URLs that are "close" (all archie servers in
North America) are grouped and then returned in a random order. Then, a
geographic location might be useful.
Anyone have a good idea here for the archie case?
-- Dirk Herr-Hoyman | CyberBeach Publishing | Practice * Internet publishing services | random acts of kindness Lake Worth, Florida, USA | and hoymand@gate.net | senseless beauty +1.407.540.8309 |