[rbak-nsp] SE800 QoS profiles

[David Freedman]

The way this is normally solved, without your LNS knowing their bandwidth and  without having to revert to changing the user's QoS profile dynamically with every re-sync based on this, is to create your product (based on the telco product) by shaping down to maxima (i.e all users who want QoS can have no more than a 2Mbit line) 
and rejecting unsuitable minima (that unless users can sync at at least 2Mbit they can't have QoS)
This way you create a uniform product, albeit restricted to 2Mbit , everybody who can sync at 2Mbit and above are shaped down to 2Mbit (and then have predictable QoS parameters) and everybody who can't achieve 2Mbit can't get the service (unless you want to have a 1Mbit product as well)

Since your provider is unlikley to prioritise traffic in their network, nor even offer an SLA, the very act of prodividing a DSL QoS product should occur in a tightly controlled environment (if at all), try taking a look at your competitors, I'm sure you will see that they do the same.


------------------------------------------------
David Freedman
Group Network Engineering 
Claranet Limited
http://www.clara.net



-----Original Message-----
From: redback-nsp-bounces at puck.nether.net on behalf of Ian Calderbank
Sent: Fri 9/4/2009 22:58
To: redback-nsp at puck.nether.net
Subject: Re: [rbak-nsp] SE800 QoS profiles
 
Hi jim,
whoever you spoke to is mistaken or misunderstood your question. certainly 
in the context of a BT 20CN iistream dsl environment (which I guess you are 
talking about) you need to know what the DSL line speed is in order for voip 
prioritisation to work , as BT won't do anything for you in their network. 
So If you don't (know the line speed) the only workaround is a lowest common 
denominator value.

I'm actually working on this with a UK ISP at the mo.

ta
Ian

--------
Calderbank Consulting Ltd
ian at calderbankconsulting.co.uk

> Message: 1
> Date: Fri, 04 Sep 2009 15:30:16 +0100
> From: Jim Tyrrell <jim at scusting.com>
> To: redback-nsp at puck.nether.net
> Subject: [rbak-nsp] SE800 QoS profiles
> Message-ID: <4AA12478.1070206 at scusting.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Hi,
>
> I want to create and apply some QoS profiles so that protocols such as
> VOIP get priority on certain users connections.  ie If the user has an
> 8Mb connection then VOIP should get priority over all their other
> traffic up to say 6Mb.  But if the user had a 2Mb line we may want VOIP
> to get priority up to 1.5Mb against the users other traffic.
>
> Our users have DSL connections and sync anywhere between 512k and 24Mb
> but we dont necessarily  know what all the users sync speeds are.  So my
> question is, do we need to know what the end users actual line speed is
> in order to apply QoS and prioritise their various protocols?  I  was
> told by a Redback engineer that you dont need to know the end user line
> speed as you can just use rate percentage in the qos profile?
>
> Is this right as I dont see how the SE800 could prioritise traffic
> without knowing what the upper limit is?  The SE800 is sending the
> traffic to the user in an L2TP tunnel though a GigE card so surely it
> would need to know the user has a line rate of 8Mb so that when overall
> traffic for the specific user starts hitting that limit it needs to
> start dropping/queue the lower priority packets?  Otherwise as far as
> the Redback is concerned wouldnt the upper limit be the GigE port?
>
> Thanks.
>
> Jim.
>
> 

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