Re: wccpv2 and multiple routers?

On Sat, Dec 02, 2006, Henrik Nordstrom wrote:

> Cisco IOS apparently has a bug/misfeature in that it looks at the IP ID
> field of the WCCP UDP packets, and if two packets is received with the
> same IP ID number it discards them as duplicates even if the WCCP
> received ID is completely different.

Aha!

> Hmm... maybe it also works disabling PMTU-discovery when I think of it..
> Testing. Yes, that seems to work fine. "Don't fragment" no longer set
> and there is reasonable IP ID values set. So I think it should work now.
> (change committed).

I've just tested that here and it works. Great!

I'm tidying the WCCPv2 code up a bit to make it easier to be 'correct'
in the future. There's some stuff that we're currently doing thats different
from the old ACNS code which seems to work but might not be 'right'.
(Specifically: we're announcing our router view as having all members up-front;
the ACNS behaviour is to only announce routers in the router-view that its
seen.)

It does make it a bit less efficient in the hereIam path as it is generating
packets the long way for each trip through the servicegroup/routerlist;
but I think its justifiable considering how infrequently we send wccp2
packets.

I'll post diffs shortly for review.

Adrian

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