cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
694
Views
5
Helpful
6
Replies

New help with QoS configuration for my Catalyst 9407R

We obtained a new Core Switch and I am having issues configuring QoS. I have never done it before and I am trying to get this new switch configured before my long break comes up. Please help.

6 Replies 6

Mark Malone
VIP Alumni
VIP Alumni
Hi
Lots of types of QOS but for a LAN switch auto qos is probably the easiest to deploy if your not familiar

by the way i would not rush this QOS should be properly planned not just slotted in , it can have adverse effects if not planned right , you just want to avoid that if possible , most the time auto qos works well but you still need to be careful and it will need to be tested correctly too to make sure its working right , wireshark or TOS pings etc

What exactly are you deploying QOS for , what is your critical traffic that needs to be prioritized

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9400/software/release/16-6/configuration_guide/qos/b_166_qos_9400_cg.html


deploying auto qos
https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9400/software/release/16-6/configuration_guide/qos/b_166_qos_9400_cg/b_166_qos_9400_cg_chapter_00.html


I would read those docs, but auto qos trust DSCP on the uplinks and access ports would nearly cover you , if its juts general EF traffic for voice and AF for video etc

Thank you for your response. My old core switch had it in place for voice. I tried to copy and paste the original QOS line, some took and some didn't. For the most part, I have the switch configured, it is just the QOS portion that i am confused about. I never had any experience using QOS, so that is why I am posting here to gain some knowledge from the crew.

With Cisco products, QoS tends to vary most on switches as it's tied to hardware (on routers, it's tied more to software).

As Mark notes, QoS done incorrectly can be more harmful than not having QoS at all.

I'm not an advocate of auto-QoS, because it may, or may not, be optimal for your requirements. Also, from time to time, with new IOS releases, Cisco changes what auto-QoS generates.

If you're going to use QoS, I suggest you learn a bit about it, as it doesn't take much to prioritize/protect something like VoIP traffic.

For Joseph, what is the learning curve for QoS. I have 3 weeks before I hang the new core switch and I have an additional 3 weeks before employees comeback to work. I am trying to get this done and phone tested before they show up.

Learning curve for QoS depends on much/deep you go into the subject. For LANs, excluding some corner cases, often you don't need QoS as there's much more bandwidth and lower latency compared to WANs. I'm guessing beyond trying to copy the QoS you had on the older equipment, you cannot really say how effective, or not, that implementation was.

It's often the case that QoS is treated somewhat like insurance, "just in case". You only really need it where there's congestion points which are actually adverse to your traffic's service needs.

You can (again) as Mark's suggests just use auto-QoS. From the earliest implementation of auto-QoS it treats VoIP "better", so assuming it "sees" your VoIP as VoIP, at least that traffic would be protected. Conversely, unless you have a link with some form of bandwidth hog and VoIP, you probably don't actually need QoS. In either case, if you do either and you have problems, you can try the other. For either, you'll probably have a longer time frame to "study" QoS and insure what you're doing or using is suitable for your traffic service needs. In other words, likely auto-QoS and/or no QoS would likely be okay short term (and possibly long term).

Thank you for your insight. I guess time will tell and I just have to be ready for those nuances when they show their heads.

Getting Started

Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: