From: Scott Morris (swm@emanon.com)
Date: Fri Mar 19 2004 - 11:16:34 GMT-3
I'm not sure I'd say it's 'rare'. But it depends on what your application
is. For example, an ASP network really doesn't have "clients" the way we
think of user PCs. So there application for a web cache may ONLY be for the
servers. They think the user-centric version is 'rare'. In an enterprise
network, the focus is on the users, not the servers, so the opposite may be
true.
In the CCIE R&S lab, I would agree that the application for server caching
would be unlikely. Not to say that it will never show up though. You know
the "anything is possible" rule! :)
That's why it's good to understand the technology though.
Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, CISSP,
JNCIS, et al.
IPExpert CCIE Program Manager
IPExpert Sr. Technical Instructor
swm@emanon.com/smorris@ipexpert.net
http://www.ipexpert.net
-----Original Message-----
From: William Chen [mailto:kwchen@netvigator.com]
Sent: Friday, March 19, 2004 9:11 AM
To: swm@emanon.com; ihatecisco@att.net; 'Ng, Kim Seng David (David)';
ccielab@groupstudy.com
Subject: Re: Confirmation on my understanding of WCCP
Hi Scott,
Thanks, I think I understand the case.
I think Web-cache is mainly used for improve the reponse when client
access the web server. It is rare to have a cache engine to be located at
the same network as the web server, but still it is a valid case.
Thanks a lot.
Best Regards,
William Chen
----- Original Message -----
From: "Scott Morris" <swm@emanon.com>
To: "'William Chen'" <kwchen@netvigator.com>; <ihatecisco@att.net>; "'Ng,
Kim Seng David (David)'" <ksng@avaya.com>; <ccielab@groupstudy.com>
Sent: Friday, March 19, 2004 9:55 PM
Subject: RE: Confirmation on my understanding of WCCP
> Again, it's a perspective thing.
>
> Typically, we think of working for clients. From that, the web requests
> come IN from our local LANs and go OUT towards the Internet.
>
> For local server caching stuff, we look the opposite direction. The only
> times web requests will come IN from our Internet-connected interface is
if
> they are looking for our local web servers.
>
> So the same principles apply. Pick the Internet-connected interface, use
> the redirect "in" command and that will provide caching support for your
> local web servers.
>
>
> Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, CISSP,
> JNCIS, et al.
> IPExpert CCIE Program Manager
> IPExpert Sr. Technical Instructor
> swm@emanon.com/smorris@ipexpert.net
> http://www.ipexpert.net
>
>
>
> -----Original Message-----
> From: William Chen [mailto:kwchen@netvigator.com]
> Sent: Friday, March 19, 2004 8:49 AM
> To: swm@emanon.com; ihatecisco@att.net; 'Ng, Kim Seng David (David)';
> ccielab@groupstudy.com
> Subject: Re: Confirmation on my understanding of WCCP
>
> Dear Scott,
>
> Can you say more about how the "caching for your won servers" be done
by
> WCCP?
>
> Thanks a lot.
>
> Best Regards,
> William Chen
> ----- Original Message -----
> From: "Scott Morris" <swm@emanon.com>
> To: "'William Chen'" <kwchen@netvigator.com>; <ihatecisco@att.net>; "'Ng,
> Kim Seng David (David)'" <ksng@avaya.com>; <ccielab@groupstudy.com>
> Sent: Friday, March 19, 2004 9:46 PM
> Subject: RE: Confirmation on my understanding of WCCP
>
>
> > The "in" or "out" is from the perspective of the router. Requests will
> > either be inbound to an interface or outbound towards someplace else.
> >
> > Your reality may be caching for your own servers, or for client
> requests....
> > Has nothing to do with the commands though. Just the routers'
> perspective.
> >
> >
> > Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713,
CISSP,
> > JNCIS, et al.
> > IPExpert CCIE Program Manager
> > IPExpert Sr. Technical Instructor
> > swm@emanon.com/smorris@ipexpert.net
> > http://www.ipexpert.net
> >
> >
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> > William Chen
> > Sent: Friday, March 19, 2004 8:02 AM
> > To: ihatecisco@att.net; Ng, Kim Seng David (David);
ccielab@groupstudy.com
> > Subject: Re: Confirmation on my understanding of WCCP
> >
> > Hi,
> >
> > Sorry, I don't understand what is the different you mean by Client
side
> > web caching and Server side web caching.
> >
> > I think WCCP is always: Client --> Cache Engineer ---> Web Servers.
> >
> > "In" means inbound traffic will be checked for redirection, and "Out"
> > means outbound traffic will be checked for redirection.
> >
> > Am I misunderstand?
> >
> > Best Regards,
> > William Chen
> >
> > >
> > > The Out would be used for redirecting outbound requests to the
internet.
> > > {Client side web caching}
> > >
> > > The In would be used for redirecting inbound requests from the
> > > internet {server side web caching.}
> > >
> > > ip wccp <service> redirect
> > > To enable packet redirection on an outbound or inbound interface using
> > > Web Cache Communication Protocol (WCCP), use the ip wccp service
> > > redirect interface configuration command. To disable WCCP redirection,
> > > use the no form of this command.
> > >
> > > ip wccp service redirect {out | in}
> > > no ip wccp service redirect {out | in} Syntax Description
> > >
> > > service
> > > Specifies the service group. You can specify the web-cache
> > > keyword, or you can specify the identification number(from 0 to 99) of
> > > the service.
> > >
> > > redirect
> > > Enables packet redirection checking on an outbound or
> > > inbound interface.
> > >
> > > out
> > > Specifies packet redirection on an outbound interface.
> > >
> > > in
> > > Specifies packet redirection on an inbound interface.
> > >
> > >
> > >
> > >
> > > ***A small point to note
> > > Its a good idea to make sure that you check all commands to see if
> > > they
> > need
> > > a special command to be enabled before assuming they are configured.
> > >
> > > I know some features like mls qos, WRED & Switches-Port Security can
> > > burn you if you aren't paying attention, and forget to enable them.
> > >
> > > ----- Original Message -----
> > > From: "Ng, Kim Seng David (David)" <ksng@avaya.com>
> > > To: <ccielab@groupstudy.com>
> > > Sent: Friday, March 19, 2004 5:27 AM
> > > Subject: Confirmation on my understanding of WCCP
> > >
> > >
> > > > Hello group,
> > > >
> > > > I just would like to confirm my understanding on the "ip wccp
> > > > redirect
> > > OUT" command. Gone through the grpstudy archives, doc cd and cisco.com
> > > but just to make sure I get it right. I had no problems understanding
> > > the
> > other
> > > "redirect in" cmd though. Anyway, I have taken the following config
> > example
> > > from doc CD:
> > > >
> > > > "Running a Web Cache Service Example The following example shows a
> > > > web cache service configuration session:
> > > >
> > > > router# configure terminal
> > > > router(config)# ip wccp web-cache
> > > > router(config)# interface ethernet 0 router(config-if)# ip wccp
> > > > web-cache redirect out "
> > > >
> > > > My understanding from the above config is that any http request
> > > > outgoing
> > > from interface e0 will be re-directed to some other interfaces where
> > > the web-cache is residing. Interface e0 would likely be a connection
> > > to the internet or where a web server is located. Interface e0 will
> > > not be where the web-cache is located.
> > > >
> > > > Is my understanding correct?
> > > >
> > > > Thanks in advance
> > > > David
> > > >
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