[c-nsp] MPLS VPN QoS on a SP core

[Mikael Abrahamsson]

On Mon, 18 Aug 2008, Sami Joseph wrote:

> Hi Mikael,
>
> I am not going to do in my Core but i'm just curious how this is done?
>
> So i guess if we want to differentiate between VPNs in my core then we need
> alot of different classes which is not really available and thats what makes
> it difficult?

QoS has many meanings.

For me at least, it's implemented by packet marking at ingress and per-hop 
queuing decisions made by core routers of which the marking influences 
which queue a packet should be put into.

I always recommend a KISS (keep it simple stupid) approach, the fewer 
classes you can have, the less complicated it is to handle. Best of all, 
is to make sure your statistical overbooking means you never have lines 
that are full, thus negating the need for QoS alltogether.

I'd say reasonable amount of queues/classes is around 4-6, one for VoIP, 
one for Video, one for priority data (interactive applications) and then 
an best effort class. You might want to put all your VPN traffic into 
priority data and let your Internet uses get a lower SLA if you mix 
Internet and VPN traffic in your core.

-- 
Mikael Abrahamsson    email: swmike at swm.pp.se