[cisco-bba] TCP and PPPoE problems with one type of CPE

Frank Bulk frnkblk at iname.com
Sat Jun 23 21:41:44 EDT 2007

You just need to go back two months on this listserv to see that having the
VJ compression attribute on the RADIUS profile was a major CPU penalty for
our 7206VXR....we changed things such that only if the NAS was our RAS box
would the VJ compression attribute be used.  This was a leftover item from
our dial-up days.


-----Original Message-----
From: Robert Blayzor [mailto:rblayzor at inoc.net] 
Sent: Saturday, June 23, 2007 5:54 PM
To: Frank Bulk
Cc: cisco-bba at puck.nether.net
Subject: Re: [cisco-bba] TCP and PPPoE problems with one type of CPE

Frank Bulk wrote:
> Interesting...were you able to turn off header compression for just that
PPPoE connection using RADIUS attributes, or did you have turn it off for
that PPPoE terminating interface?

Our RADIUS server sent VJ back to the router, but the router on PPP
interfaces is passive by default.  If we implicitly turn it off, then
the Zyxel doesn't send compressed headers.

> What happened when you turned TCP header compression explicitly on?

Forced on would be bad.  Since I have thousands of customers behind this
virtual template there was no easy way to turn it on for just this one

By default I think our RADIUS server sets VJ on (thus making compression
optional), but none of the clients ever really use it. (since it's
broadband after all).  I think our new policy will be to just turn off
header compression completely.  I think this was popular with lower
speed connections like dialup and ISDN, but now with our minimum pipe
being 512-768K, it's not really an issue anymore.  In fact, I think it'd
be rather taxing on the BRAS if we did compress all that broadband since
the word on the street is it causes the packets to become processed

Robert Blayzor
rblayzor at inoc.net

Design: The activity of preparing for a design review.

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