[nsp] l2tp-cpu load

[ALBERTO.CITA at telefonica.net]

I'm currently planning on deploying a distributed PPPoA broadband 
aggregation layer in our backbone network with Cisco 7206VXR boxes 
(with NPW-G1 hopefully). And I would be thankful to anyone who could 
share his/her experience within this kind of deployments.

I'm looking for some real-world escalability figures (number of 
simultaneous PPPoA sessions) with any kind of NPE, similar to the ones 
provided so far in this thread for the Cisco 7200s boxes in the LNS 
role (I already know of official Cisco figures).

Thanks a lot in advance.

Best regards,
Alberto Cita.



----- Mensaje Original -----
De: Andy Furnell <andy at furnell.org.uk>
Fecha: Viernes, Noviembre 28, 2003 1:27 pm
Asunto: Re: [nsp] l2tp-cpu load

> On Fri, Nov 28, 2003 at 11:05:26AM +0000, H S wrote:
> > 
> > Hi !!
> > 
> >        I have a Cisco 3640 and have set up an l2tp tunnel. I 
> wonder how 
> > many simultaneous sessions will it support. Currently, I have an 
> average of 
> > 16 sessions and 26 % of CPU load. The traffic through the 
> interface is not 
> > much (1 Mbps) and (400 pps) I?m planning to change the 3640 by a 
> 7204 
> > (NPE-400) but I would like to know it?s limitation on this issue.
> > Could anyone advise me?
> > 
> > Thanks in advance!!!!
> > 
> > Regards
> > 
> > Hugo
> 
> Hi Hugo,
> 
> I had an NPE-400 terminating ~1500 l2tp dial sessions at around 
> 45% CPU... 
> This box was also handling a couple of PA-MC-E3 and a PA-MC-STM1 
> with a total
> traffic load of about 35mbit/sec and ~15kpps. This took some 
> messing around
> to get CPU usage below 60%... PPP compression is right out the window,
> and vpdn ignore udp checksum in your global config will reduce CPU 
> usage by
> another 10-15%. The only problems we ran into were with virtual-access
> interfaces not being re-used - the only solution for this at the 
> time was
> to reload the machine every month, but this bug may well be fixed 
> in a more
> recent IOS release. As far as IOS releases go, we had the best 
> luck with 
> 12.2(8)T, although I've heard good things about 11T and 15T, as 
> well as 12.3
> mainline.
> 
> Remember the number of tunnels will affect performance much more 
> than the 
> number of sessions... if you can aggregate the l2tp tunnels so 
> only one tunnel
> is presented to your LNS you'll get much better performance than 
> if you're 
> forming hundreds of l2tp tunnels to hundreds of LACs with a 
> similar number
> of active sessions.
> 
> If the cash is there you'll have get much better performance from 
> an NPE-G1.
> >From speaking to people using them as a broadband LNS they seem 
> to be able
> to take an STM-1's worth of traffic in about 5500 sessions without 
> breakinga sweat :)
> 
> A
> 
> -- 
> Andy Furnell
> andy at furnell.org.uk
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