> Patrick McManus wrote:
>
> > server side proxies are not really proxies at all.. they're just
> > origin servers typically implemented that way so clustered hardware
> > can be used (yielding fault tolerance, division of labor, and things
> > like filesystem optimizations).. but they are origin servers without a
> > doubt.. the fact that they fufill some of their requests using HTTP
Joe Touch answered:
>
> So it sounds like this is just a server, period.
To say that a caching reverse-proxy (the most common server-side caches
deployed outside the internal operation of the HTTP server) is just a
server is perhaps a oversimplification. To the client it behaves like a
server, but the implementation and properties is more that of a caching
proxy. The main properties differentiating it from a "caching proxy" is
the clients view of what and where the service is and how and by whom it
is deployed.
Even more so for non-caching reverse proxies. These are often only
relays with close to no HTTP server functionality at all. All data
processing is then done by the real server(s).
The generic term "server-side caching" is a property of the service and
can be implemented in any manner. Details of such a generic term is
clearly outside the WREC scope as it edges on server
design/implementation.
"server-side caching proxy" or "caching reverse-proxy" is one way to
implement "server-side caching" using a separate "box" utilizing
protocol techniques of a caching proxy, possibly combined with
out-of-band information. This technique can be used to implement a form
of "mirroring"/"site replication", and is why it is of importance to
WREC.
"reverse-proxy" without caching or where caching is not the primary task
is a very much different issue. The most common application is acting as
a trusted relay. This function is also outside the scope of WREC.
To me it is clear that we need a definition for a proxy-cache like
device ("server-side caching proxy", "caching reverse-proxy" or whatever
name we find suitable) intended to be placed infront of a server,
caching server responses and acting to clients as if it was a
authorative source. This identifies a important set of service
mirroring/replicating models/techniques suitable for future
investigation, AND is a technique actively deployed today.
Due to the composite nature of the function such a device performs, and
the close relationship to the functions performed by a "caching proxy"
the definition should probably be second or third level based on
"caching proxy" and something else which binds it to the origin server
side from both the clients and site administrators point of view.
-- Henrik Nordstrom
This archive was generated by hypermail 2b29 : Thu Nov 18 2004 - 11:21:27 MST