6500 QoS question

mattsthe2

So im deploying my very first 6500 pair of switches with the sup720. So excited to be working with this high end equipment that costs as much as a house!

Anyway my experience lacks on QoS, cant wait till i get to that part of my studies.

I've enabled mls qos globally on the 6500, but my question is on qos trust types.

For uplinks from other switching closets should i use:

mls qos trust dscp or cos?

the same question for our CallManager and Unity/IPCC servers and phones that plug directly into it. For example we have a Cisco ATA box that we use for paging. Cos of dscp on the port interface(s)?

thanks.

Mrock4

What is the role of these switches? Where will they be positioned in the overall network? Within your network using CoS is relatively standard practice, if you're working on a bigger scale and the tagged traffic will be routed, DSCP may be a better decision. If there is already a QoS policy in place, I would go with the most consistent method, and trust what is already being used.


Also, what kind of phones are you using?

mattsthe2

it will reside in the data center. Mostly servers that connect into it.
All of the switch closet uplinks are routed via .1q layer 2 STP. We dont use L3 routing to our switching closets.

The phones are typically Cisco Phones 7961/41's.
And on the Access switches we typically enable mls qos and place mls qos trust device cisco-phone on each phone port.

The only QoS policies in place live on the routers toward our WAN (which will also connect into these 6500's).

Our video confering stations are being tagged at DSCP.

Do i just do an mls qos trust dscp on the 1.q uplinks?

Mrock4

Ideally, you want your trust boundary as close to the source as possible. What I mean is, by default, the Cisco IP phone will have a CoS of 5. In an ideal setting, the access switch that it connects to should trust the CoS from that Cisco phone, and have a CoS-DSCP mapping...then the rest of the network is DSCP (so you'd just trust DSCP from that 6500 and on..).

Edit: If you're not familiar with the trust boundary, it's simply where your network starts "trusting" QoS marking. This is so that you have your edge devices (phones, access layer switches, etc) performing classification/inspection, and not your distro/core devices.