how to prioritize dscp packets entering my network

I have an x450 extreme summit switch in my network with all types of traffic and no QoS policy setup. I have a server outside my network that sends traffic into my network. These packets come in with an IP header value/Diffserv = 51

How can I get my switch to prioritize the packets tagged with diffserv 51 to make sure I don't drop these packets?

6 replies

Userlevel 4
Here is a simple configuration example.

# create qosprofile qp5
# disable dot1p examination ports
# enable diffserv examination ports
# configure diffserv examination code-point 51 qosprofile qp5

For more details, you may want to visit the link below.
Followed your steps. I see that qp1 and qp8 are already created on the switch and have the same weight as my new qp5. Do i need to do anything with qp5's weight to make sure those packets get priority?

# show qosprofile
QP1 Weight = 1 Max Buffer Percent = 100
QP5 Weight = 1 Max Buffer Percent = 100
QP8 Weight = 1 Max Buffer Percent = 100

Thanks for your help so far!
Userlevel 4
I assume you would use the strict priority scheduding. If so, you don't need to change weight which is for WRR. The higher queue will be processed first in the strict priority scheduler.
How can I implement the strict priority scheduling? The switch is currently "dumb" except for some VLANs and ip addresses.
Userlevel 4
My apology. I should have mentioned it earlier. The strict priority scheduling is set by default. You can change scheduling by 'configure qosscheduler [strict-priority | weighted-round-robin]' command.
Userlevel 6
If you have already followed the steps mentioned by Kevin, you can check the egress queue traffic per port using the command below:

show ports qosmonitor

The output will show the corresponding egress queue (QP5, for instance) incrementing.

You can check the article below for some additional explanation:

Configuring QOS profiles and verify QOS is working on EXOS