QoS on Trunks

[Brian Aeschliman]

We run both VOIP and video over a multi-site WAN MPLS. We have our UCS server in our Michigan site and it operates about 150 phones in our North Carolina site. I have setup QoS on the switchports that the phones are connected to. I have seen that some engineers setup QoS on their trunking ports as well. My question is, should QoS be applied to trunks as well as access ports and if so what benefit does it provide?                  

[Joseph W. Doherty]

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Posting

As trunks aren't immune to congestion, you may want QoS on them for reasons similar to other congested ports.

The big difference between a trunk port vs. an access port, the latter may/should deal with initial trust issues.  Hopefully, by the time traffic is on a (transit) trunk, congestion QoS is the only issue.

[Alessio Andreoli]

Hi Brian,
even if I fully agree with Joseph, a common design prefers to over provision trunk capability rather than implementing QoS on the trunk ports. On the other hand, maybe the geographical distance requires particular markings (Voice and Video) and prioritisation in order to reduce the processing and serialisation delays.

Hope this helps
Alessio

Sent from Cisco Technical Support iPad App

[Juan Urti]

Hi, like Joseph says, the trunk are practically inmune to a congestion.

But, you must configure cos/dscp trust on this port, to avoid that the switch remark the frames or packets.

Good Bye.

Juan