Re: WCCPv2 issues

From: Henrik Nordstrom <henrik@dont-contact.us>
Date: Wed, 26 Jul 2006 02:11:16 +0200

ons 2006-07-26 klockan 11:27 +1200 skrev Reuben Farrelly:

> > Regarding the mask based assignments, wonder how complex mask arrays a
> > typical equipment supports. In the specs is an unbounded array.
>
> Does this help?
>
> http://www.cisco.com/en/US/products/hw/switches/ps4324/products_configuration_guide_chapter09186a008062cfc6.html
>
> especially
>
> "WCCP version 2 standard allows for support of up to 256 distinct masks.
> However, a Catalyst 4500 series switch only supports mask assignment table with
> a single mask."

I suppose this means a single mask/value set.

Wonder if there is any limit on the size of the value set.. hopefully
not too small or load distribution will be a bit troublesome. A single
mask is sufficient provided the value set can be sufficiently large.

But in worst case this means a single mask value per cache member
server, which kind of limits possible setups to power of 2 cache servers
as all other configurations will have IP areas which can't be redirected
if only a single mask value per cache server is supported.

A quick math. They say it supports up to 32 cache servers. Then
hopefully they support at least 64 mask values to allow for some kind of
distribution.

Btw, not sure where they found the supposed standard limit of 256..
nothing mentioned in the last draft I have access to, and the field with
is 32 bits... The only 256 limit mentioned is the hash size for hash
distribution which is using 256 buckets (fixed size).

Regards
Henrik

Received on Tue Jul 25 2006 - 18:11:20 MDT

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