Best Practices for QoS on WAN Links (Voice/Video Traffic)

[MD Irshad Ansari]

Hi Cisco Community,

I wanted to ask about QoS for WAN links where both voice and video traffic are present.

My questions:

1. Do you prefer using LLQ (Low Latency Queuing) for voice and shaping video separately?
2. Any real-world challenges with DSCP markings not being preserved between providers?
3. What’s your go-to method for testing/validating QoS policies after applying them?

Thanks

[ammahend]

Generally speaking

1. Voice traffic should go into a strict priority queue, Video traffic typically in a dedicated class with guaranteed bandwidth but not LLQ, to avoid starving other traffic.

2. common in MPLS or SD-WAN deployments,Providers remark or strip DSCP values, especially EF and CS6. best it to with with them and re-mark at WAN edge routers to align with provider-supported markings.

3. without using any tool, show policy-map interface, Validate packet counts, match counts, drops, and bandwidth usage per class, 
Check if traffic is actually matching intended classes.

you can also follow standard Cisco documentations

It has some config examples as well.