[cisco-bba] PPPoVPDN scability

Andy Schutz (aschutz) aschutz at cisco.com
Wed Dec 10 20:15:15 EST 2003


While I haven't tried this specifically, my guess is that you are
punting packets from the PXF path to the RP by using the tcp-adjust-mss
command.  The NSE1 is a pxf enabled platform and the subsequent scaling
claims are based on using the pxf for packet forwarding.  If you are
forced to use the RP (which is there for punted traffic that is control
plane oriented) as the forwarding plane, you can see a reduction in

I would suggest trying either with ATM instead of Ethernet so
tcp-adjust-mss isn't needed or trying with a non-PXF platform (NPE-G1
for example).

For verification that packets are getting punted, try "show pxf
accounting ..."



> -----Original Message-----
> From: cisco-bba-bounces at puck.nether.net 
> [mailto:cisco-bba-bounces at puck.nether.net] On Behalf Of Martin
> Sent: Tuesday, December 09, 2003 11:57 AM
> To: cisco-bba at puck.nether.net
> Subject: [cisco-bba] PPPoVPDN scability
> Hi,
> we are running a 7204/NSE1 to terminate a couple thousands 
> PPPoVPDN aka PPPoEoE sessions. Since the tunnels are over 
> ethernet, we  have to tcp-adjust-mss to 1412, but let the 
> virtual-template interface to 1492 to accomodate broken PPPoE 
> implementations that won't fragment to 1452. This setup gives 
> approx. 50% cpu usage at 30mbit out/20mbit (6kpps/5kpps) 
> in on the interface facing customers, which doesn't sound 
> anywhere close to the advertised specs (wire speed aggregation).
> Does someone know how an NPE-G1 would scale in our actual 
> situation? And what would be the upgrade path alternatives to 
> effectively be able to aggregate 90mbit worth of traffic on a 
> single box, if the NPE-G1 can't do it?
> One last question, what would be the gain if we terminated 
> the tunnels on a ATM interface (which would solve the 1452 
> MTU problem I believe) instead of FastEthernet?
> thanks,
> -Martin
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