Re: Transperant HTTP Redundancy.

From: Eric Stern <>
Date: Tue, 24 Mar 1998 11:12:34 -0500 (EST)

On Tue, 24 Mar 1998, Chris Keladis wrote:

> Hi folks,
> We have transperant proxy'ing working fine with various Cisco's and Squid in
> a test environment.
> One thing holding us back from implementing transperant proxy's is
> redundancy. We have tried using "set ip next-hop" with multiple "next-hops"
> but once the first hop stops responding it doesnt go to the next hop. Even
> clearing the ARP tables didnt help.
> We *did* however find, if we made the first hop a serial interface of the
> Cisco and bought that interface down, it *did* go to the next hop (the
> Serial interface being internal to the Cisco).
> We are debating using OSPF or IGRP and trying things that way i was just
> wondering if anyone else has come up with another method of redundancy on
> their Squid proxy servers using Cisco routers?

Well, sort of. I'm working on a unit that can provide redundancy and/or
load balancing for my WebSpeed proxy units (although it will work with
anything). I'm calling it TrafficCop. Basically, you would redirect all
HTTP traffic to TrafficCop via Cisco's tranparent proxy feature, and then
TrafficCop will route that traffic to one or more cache units.
Alternately, you can insert the TrafficCop unit into your network in such
a way that all your internet traffic must pass though it, and it can pull
out and redirect HTTP traffic itself (you'd want this if you don't have a
Cisco capable of doing transparent proxy for you).

I'm working on a mechanism so that local cache units can announce
themselves to TrafficCop as well (just like Cisco's WCCP). Also,
TrafficCop will test all the cache's it knows about periodically, and if
it goes down will take it out of service.

Note that TrafficCop could also be used to load balance web servers, as
well as cache servers.

Of course, installing a TrafficCop still leaves you with a single point of
failure (ie if TrafficCop dies, you are SOL), but I think that the
TrafficCop unit is MUCH more reliable than a cache machine. The only thing
I really worry about with cache units is hard drive failures, and I'm
trying to design TrafficCop without a hard drive. Next on the list is the
power supply. If I build the unit in a case with dual redundant power
supplies, I think you'd be looking at a pretty reliable piece of hardware.

I'm aiming for $2500 US as the sale price, and it should handle up to
about 45Mbps without too much trouble. Won't know for sure until I get to
testing, of course.

/ Eric Stern - PacketStorm Technologies - (519) 837-0824 /
/ /
/ WebSpeed - a transparent web caching server - available now! /
Received on Tue Mar 24 1998 - 08:32:28 MST

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