Re: [SQU] REG: GRE Encapsulation of WCCP redirected packets.

----- Original Message -----
From: "Henrik Nordstrom" <hno@hem.passagen.se>
To: <neelaj@future.futsoft.com>
Cc: <squid-users@ircache.net>
Sent: Monday, November 06, 2000 8:31 PM
Subject: Re: [SQU] REG: GRE Encapsulation of WCCP redirected packets.

> neela priya c wrote:
>
> > The purpose of GRE encapsulation of WCCP redirected data
> > packet is to redirect the packet destined actually to the
> > web server to the cache engine without altering the IP header
> > of the data packet. The data packet IP header (IP-1 header)
> > contains the IP address of the WEB server.
> > The second IP header(delivery header IP-2 header ) contains the
> > IP address of the Cache Engine.
>
> Correct, in all aspects.
>
> My only concern is why Cisco selected to make a new GRE protocol type
> instead of using the existing for encapsulated IP... but maybe they
> wanted to make life a little harder for cache OS implementations...
>
> --
> Henrik Nordstrom
> Squid hacker
>
> --
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>
>

I can suggest a reason: to allow simple filtering of the encapsulated data
on other routers than the one performing WCCP. Possible reasons for this:
complex acl's do not need to be duplicated - reducing load on core routers;
getting WCCP traffic through acl's that otherwise prevent GRE passing...

Rob

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