There seem to be three solutions for transparent web-caching:
1 a web-cache between two routers, all traffic is routed through it.
2 a l4 switch between two routers, all traffic is routed through it.
The l4 switch redirects web-requests to a www-cache.
3 a web-cache connected to a router which uses policy routing to
direct web-requests to it.
1 is extremely ugly and impossible at high traffic levels
2 is an extra device in your network which needs to be managed
and is often difficult to implement in a WAN environment (our
core routers don't have (fast-)ethernet interfaces.)
3 is the preferred solution but you need to run 11.3 or 12.0 for
it. These software versions support fast-switched policy routing.
Most ISPs currently rely on 11.1CC features and thus can not upgrade
to 11.3. The wait is thus for a stable release of 12.0.
-- Steven
In your mail from 17-11-1998 you write:
stevenh@inet.unisource.nl (steven hessing) writes:
There seem to be three solutions for transparent web-caching:
1 a web-cache between two routers, all traffic is routed through it.
2 a l4 switch between two routers, all traffic is routed through it.
The l4 switch redirects web-requests to a www-cache.
3 a web-cache connected to a router which uses policy routing to
direct web-requests to it.
There's a fourth. I used to manufacture something called the Web Gateway
Interceptor which was topologically a router. It wasn't competitive as
a router, either in price, performance, or number/kind of interfaces. But
you could put it in parallel with another router and integrate it into
your OSPF mesh and use OSPF link costs to make it be the primary path only
while it was up. HSRP would have worked the same way, and I'll admit that
it's a lot simpler to do (though I'm not sure it's an open standard yet?)
paul@vix.com (Paul Vixie) writes:
There's a fourth. I used to manufacture something called the Web Gateway
Interceptor which was topologically a router. It wasn't competitive as
a router, either in price, performance, or number/kind of interfaces. But
you could put it in parallel with another router and integrate it into
your OSPF mesh and use OSPF link costs to make it be the primary path only
while it was up. HSRP would have worked the same way, and I'll admit that
it's a lot simpler to do (though I'm not sure it's an open standard yet?)
HSRP is published as an Informational RFC.
However, there is a patent on the protocol, assigned to Cisco. To the best
of my knowledge, Cisco has not granted any licenses to that patent (yet).
The VRRP working group selected the VRRP protocol instead of HSRP to place
on the standards track, so at this point, it is unlikely that HSRP will
become a standard (open or otherwise) anytime soon.
Tony