I guess I should have been specific about our circumstances.  We're
replacing an older Compaq TaskSmart cache server and we want to get two
of something or other, and we're having a hard time making up our minds.
 Today I got the bright idea that we could simply buy two Sun Netra
servers and put Squid on them.  Sounds like a good idea to me but I
wanted to hear the opinions of other Squid users.

Thanks!
John

>>> "dre"  9/12/02 3:04:07 PM >>>
""John Neiberger""  wrote in message
> Are any of you using the Squid open source software on your own
> hardware?  If so, are you happy with it?  How does it perform in
> comparison to other caches you've used?

I like Squid.  ICP multicast seems like a very intelligent way to move
content around.  Content encapsulation with mod_gzip is nice on the
sending side, but more people need to be caching content on the
receiving side!!!

Cache hierarchies are very nice, but as a content provider (no names
here),
I can tell you that all the CDN's and cache hierarchies in the world
aren't
going to solve any real world problems.  Cache hierachies are for
end-users,
not content providers.

Direct interconnection and/or smart routing (BGP performance and
correct
operation of multi-homed networks) has been and also currently is the
champion for content providers, and where they should put the most
investment in.  Private/Public peering is also a better cost
optimization
(by
leaps and bounds!) for heavy content providers than CDN's or cache
hierarchies.  Another big responsibility for content providers (and a
MUST
if they want to save huge amounts of time and money) is to provide the
ability for their content to be cached by end-users and Tier-2's.  The
book
"Web Caching" by Duane Wessels is excellent as are the RFC's. 
However,
this is not a networking problem, it's an HTML and coding problem.

While Cisco and Akamai don't understand this at all, they seem to be
pushing their products to the wrong people, IMO, and this is why their
product lines are suffering.  DNS content routing mechanisms (e.g. RR
DNS,
Cisco Boomerang, Cisco DD, Radware Global Triangulation, et al) are
proving to not work (because of DNS servers caching TTL's).

To put this in easier terms, content routing can be done in a few
forms:
* DNS mode - done by client's DNS (not direct end-user), DNS server
caching
   avoids adminitratively set TTL's, can be bypassed by using IP or
different DNS
   name (http://yahoo.com instead of www.yahoo.com)
* HTTP-Redirect mode - browser problems, bookmarks can bypass, DNS
   caching can still avoid administratively set TTL's (same problems
really)
* Edge-Intercept - now this does avoid DNS caching, but requires access
to
   all the end-users and network.  Still has problems with multi-homed
users
or
   users attempting to use different DNS servers.
* BGP + Anycast - only real method that I know to solve global
reachability
of
   services across distributed data centers.  Done with IP addresses
(announcing
   single multi-homed blocks in more than one place, with /32's
reachable
for single
   IP's throughout the internal infrastructure (since you can't
announce
anything
   greater than a /24 in the Internet routing table).  Anycast
addresses are
injected
   into the IGP (could be IBGP, doesn't have to be OSPF/EIGRP/ISIS)
and
marked
   with metrics showing distance.  See the following paper for more
details:
  
http://www.cisco.com/public/cons/isp/essentials/ip-anycast-cmetz-03.pdf


Cisco's IOS SLB and the Catalyst 6500 CSM have a feature called "Route
Health
Injection", or RHI, which is capable of injecting a /32 host route and
pulling it out of
the routing table if the server (or VIP) is not available.  The most
current
Cisco SRND's
(e.g. Enterprise Data Center Design) and Cisco Sales Positioning are
now
recommending
the use of RHI for content routing.  I believe that investments should
now
be going into
using this technology instead of letting people like Akamai invest in
secrets like this for years.

Going back to caching, I think the basics can be implemented by the
content
providers
(such as using Reverse Proxy Caching (RPC) to replace use of servers
and aid
against
"flash crowd" problems, etc).  What I feel is more on the Enterprise
or
ISP/User side
is use of cache hierarchies or CDN's.  The strongest caching
architectures
should be
found in those places, as they will have the most cost optimization
and
performance
benefits from implementing such a solution.

Here's a link to the Cache Now! campaign -
http://vancouver-webpages.com/CacheNow/ 

I am very interested on the AOL cache architecture.  They seem to be
the only people who have "figured it out".  If anyone has any details
of
what they use / what they do, please post or email me privately.

-dre




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