I am trying to setup CoS, QoS and queuing across our MPLS network through our service provider. We don't run any MPLS natively; it is all done by them. Most of the materials I have and references on Cisco's web site don't mention MPLS that much, so I'm not quite sure which "kind" of congestion control or avoidance I should implement.
We have a 45Mb DS3 at our datacenter, and multiple smaller sites with either single T1's or dual MLPPP bonded T1's. We are all meshed and everyone routes to everyone equally through OSPF. 'Very nice network, and much better than our old AT&T Frame-relay. My problem is I want to do QoS for VoIP through my network and I'm scratching my head as to the best method given the network.
As everyone here knows, with most direct point-to-point links such as T1, the egress speed is identical to the ingress speed. 1.544 =1.544. Your only concern is to apply appropriate queuing out of the serial interface to prioritize your favorite packets in whatever order you see fit. LLQ, CBQ, Fair-queueing, FIFO, whatever. It'll simply travel down the pipe and be received in that same order. However, with dissimilar link sizes, like going from a DS3 to a DS1, this can't be easily done! A 45Mb DS3 would never see it as congestion on its' side, although the poor little DS1 certainly would.
My question is -- Do most service provider's MPLS networks apply any traffic shaping or queuing mechanism within the cloud at all? Or does it need to be completely controlled by me? Are packets dropped (I assume so?) when the end node can't receive traffic as fast as the head node can send?
There are a lot of QoS and congestion avoidance mechanisms available in Cisco IOS, but most of them refer to Frame-relay. I was thinking of applying the same traffic-shaping syntax to my own Cisco routers, except that I don't have to worry about any CIR value - only port speed. There is also no MPLS equivalent of BECN's or FECN's that I'm aware of, so I'm not quite sure if the MPLS cloud would send me any feedback if packets were indeed dropped. So can I even use LLQ + CBWFQ to seperate my voice from everything else? Or do I also have to figure out generic traffic shaping and incorporate it into the mix?