(QoS/CoS) What is the most Current, 'Best Practice' for 'identifying' and 'marking' egress traffic (Video, Data) from/through an access layer 2 switch?

[1brbryant1]

(QoS/CoS) What is the most Current, 'Best Practice' for 'identifying' and 'marking' egress traffic (Video, Data) from/through an access layer 2 switch? 

From my understanding, Cisco phones 'Automatically' identify and mark VoIP traffic as DSCP EF or 46 (unless it isn't automatic)?

- Best Answer would be the optimal solution that is most scalable in a production environment

- All I'm looking for is the: 

*interface, trunk, and global configuration for the layer 2 switch*

Thank you

[Francesco Molino]

Hi 

The qos configuration depends on the switch model. 

First of all, yes all cisco phones are tagged with dscp 46 (unless if cucm admin had changed it). However, depending on your switch model you'll need to trust it otherwise it will  be at back to 0.

For example, with switches like 3750, 2960 you should enable mls qos globally and you need to trust the dscp or cos on each ports. 

On newer access switches, all ports are rising dscp value by default. Nothing to do on that part. 

Then no matter which switch model, you'll need to apply policy-map to classify traffic and set dscp value on inbound for your external facing interfaces (e.g. Trunk). Also apply policy-map to prioritize traffic or police/shape it based on what you want to do. 

If you're trying to setup standard stuff, you can find cisco best practice entreprise campus config based on your switch model. 

I attach cisco presentation related to that. 

Be careful generally with qos config because if not setup correctly you can have troubles. Specially with 3750, 2960 on which as soon as you activate mls qos it could start dropping and you'll need to tweak the config (e.g. buffers) to avoid that. 

Thanks 

PS: Please don't forget to rate and mark as correct answer if this answered your question 

[1brbryant1]

Thank you for the feedback Francesco!

Very interested in reading the pdf, but I am unable to open it (I've tried IE, Chrome, and Firefox), can you please reattach the 'enterprise_campus_qos.pdf'?  

My ongoing issue has been CoS vs QoS on the Access switch ports and the correlating Global and Trunk configurations that will allow the interface command (CoS or QoS) to function optimally.

In an effort to reply to your response, I found another thread that has been very helpful if you're interested:

https://supportforums.cisco.com/discussion/10700121/mls-qos-trust-dscp-vs-mls-qos-trust-cos

I need time to read through the articles attached to the above thread, and I'll get back to you.

Please feel free to reply with any additional information you think may be beneficial.  

Thanks again Francesco!

[Francesco Molino]

You're welcome.

Here is the link to download the file from my dropbox in case the attachment won't work.

https://www.dropbox.com/s/ivswpuimicoebtd/Enterprise_Campus_QoS.pdf?dl=0

Using mls qos command is available only on Catalyst 2960, 3750, 3560, but not on newest switches like 3850, 3650,...

On new switches, you don't need anymore to trust DSCP as it's trusted per default.

Anyway, based on devices you have, you need to ensure that even if they're working with COS value, you'll have to set the DSCP and apply the same config everywhere the traffic is flowing through.

Doing QoS is a very large topic and can be done in different ways based on hardware and what you want to achieve.

After reading, if you have any questions or need helps, give us more inputs and I'll be very happy to help.

In the PDF, you'll have some bandwidth values (based on best practices) and usually they're matching around 80% of enterprise campus networks. However, to be sure that's matching you can do a QoS assessment to validate those values. Again this depends on what you want to do. If it's just tagging/trusting voice traffic and prioritize it and let it go with full bandwidth for all the rest it's more easier..

Thanks

PS: Please don't forget to rate and mark as correct answer.

[Leo Laohoo]

I presume this is very much related to your other thread (HERE).