[rbak-nsp] qos queuing with L2TP tunnels

[Ian Calderbank]

Hi Rick,

The bandwidth shaping values on redback pwfq are in my experience extremely
accurate if you measure them with an ixia or similar. But it may indeed
depend on what level you've applied the policy as to which overheads are
counting and which aren't.

 

If you are looking to match only l2tp traffic on that port (because there is
other significant traffic) then you should be able to use a metering policy
with an acl to match the l2tp, classify your l2tp traffic with that, then
push it into a (set of) queue(s) that you want to shape.

 

It's not doing DPI (there was the ASE blade, but I guess you don't have one
of those) it should just be down to what level of circuit you've applied the
policy to as to whether its working on subscriber level or tunnel-transport
level.

 

This is a tad complex for mailing list..as I mentioned the other day, I am a
freelance consultant, you can hire me by the day J 

 

cheers

Ian

 

From: Richard Clayton [mailto:sledge121 at gmail.com] 
Sent: 12 January 2011 22:13
To: Ian Calderbank
Cc: redback-nsp at puck.nether.net
Subject: Re: [rbak-nsp] qos queuing with L2TP tunnels

 

Ian

 

It was the aggregate on the circuit towards the lac I wanted to pwfq, I
remember when I tried to do this on Cisco I could never match traffic that
was l2tp encapsulated, we ended up l2tp tunnel switching the traffic to
another lns and shaping the whole tunnel, one of my colleagues has a working
redback pwfq policy but the bandwidth shaping values don't exactly match
reality, the difference appears to be the overhead of the l2tp etc.  How
does the redback Qos inside l2tp, does it match before encapsulation or is
it doing some type of dpi.

 

Thanks

Rick

 

On 10 January 2011 10:22, Ian Calderbank <ian at calderbankconsulting.co.uk>
wrote:

------------------------------

Message: 5
Date: Sat, 8 Jan 2011 10:03:28 +0000
From: Richard Clayton <sledge121 at gmail.com>
To: redback-nsp at puck.nether.net
Subject: [rbak-nsp] qos queuing with L2TP tunnels
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       <AANLkTinqFF4Bj9GKMV_jkujRruqYv41MC9bPABzaQQym at mail.gmail.com>
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> Is it possible to perform outbound qos queuing on traffic that is
encapsulated within L2TP.

yes


>If it is possible then how is it done as I assume queuing happens after
L2TP encapsulation.



Just apply pwfq policy to the subscriber if you want per-subscriber queuing.
Be careful that the line card / EPPA that has the circuit for the subscriber
and that which has the circuit for the l2tp tunnel are the same otherwise
PWFQ won't work . I see you are discussing this with david already.

If you want to apply qos to the aggregate traffic as well / instead, you can
also apply pwfq to the egress circuit to the lac. If you try to do _both_
(subscriber and aggregate), be careful. There's no H-Qos for l2tp lns.

ta
Ian

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