New QoS Policy

wscotty2012 · ‎08-25-2012

Hi,

I need to design a new QoS policy for a new deployment that will support voice and video and i need some pointers with the design.

We have 2 large offices that will each connected by metro ethernet to our primary data centre core switch, both offices will communicate using eigrp by routing via the data centres. We then have an MPLS service connecting to the data centre, this is provided by a 3945 router managed by the service provider. The MPLS currently provides a 3 level CoS - voice, mission critical, and best effort.

Knowing this, what level of CoS is best to configure for each of the offices? We will be deploying 4500 with Sup 7s in each office. I'm looking at the Medianet campus design guide and the CoS policy for the Sup 7s use a 12 class of service policy. Will this be ok to use? Will the MPLS provider then need to classify and remark to match their policy ingress to their 3945?

Thanks,

sean_evershed · ‎08-25-2012

Hi,

I suggest that you match your QoS policy to the CoS SLAs that you have purchased from the Telco.

This means that you need to understand what DSCP values the Telco is expecting to see from your 4500 for each level of CoS. For example they may expect to see mission critical data marked as DSCP AF31.

If you mis-classify your traffic with the wrong DSCP values then the Telco will mark it down it as it traverses the WAN.

I also suggest that you enable Netflow on your network to ensure that your QoS policy is working correctly end to end across the WAN. It is also a good monitoring tool to ensure that the Telco is marking the packets according to the paid for CoS SLAs. In a previous job I found that we asked for a CoS SLA on our WAN link but the Telco had forgotten to enabled it.

Cheers

Sean

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wscotty2012 · ‎08-25-2012

Hi,

Thanks.

So if the telco is expecting to see DSCP EF for all priority traffic, voice and video in this case, does that mean I need to remark video traffic to EF as it enters the 4500? How will this affect traffic between the 2 offices which dont communicate via the MPLS?

Would it be possible to classify as per the Medianet recommendations and then ask the teleco to reclassify to their policy as traffic enters and exits their WAN routers or will this get quite complex?