QoS for port channel ports on 3850 switch

[voip7372]

We have a 3850 switch with port channels to two 2960 switch stacks and a trunk port to the WAN router.  We need to be sure we have QoS on these port channel ports so traffic from the 2960 switches can pass through the 3850 on the way to the router.  

For the trunk port to the router, we use 'auto QoS VoIP trust'.    

For port channel ports we normally use 'mls qos trust dscp' but the mls command is not available on the 3850 for those ports.   

What is the correct way to ensure the port channel ports get QoS on this switch?

Thanks

[Mecalectro]

have you found the solution?

[voip7372]

My colleague (the one that normally handles our QoS) told me he discovered the 3850 handles the traffic more like a router, so we removed the QoS entries on the port channels on the 2960 switches that link to the 3850 and on the 3850 there's no QoS entries at all.  So I'm told.  I haven't logged in to verify exactly how he has it configured now, but that's what he told me.  

[Mecalectro]

okay, i have two port-channel with two 2960 link that are connected to a 3850.
On the first switch 2960, I have ip phone and on the second I have the pabx connected, the set being placed in a vlan.

I have to carry the voip with qos through the 3850 to the pabx.

ip_phone -> first_2960 -> port-channel-> 3850 -> port-channel-> second_2960 -> pabx

I activated auto qos on the 2960 and configured the ports with "auto qos voip trust"

do you know if I have to apply configurations on port-channel 2960 and 3850?

and if I have to apply other configuration?

thank you for your reply !

[voip7372]

I just logged in and looked at our 3850 and 2960.  Our traffic flow in this case is like this (for calls that go to our WAN):  phone > 2960 stack > 3850 > router.

I wasn't involved with the changes that were made because one of my colleagues normally manages the network at this location I'm talking about, but here's what I see right now (and they tell me the voice quality is good now)...

Port channel on 2960 to 3850 has this QoS entry (the physical ports, not the channel group):

mls qos trust dscp

Port channel on 3850 connected to the 2960:

auto qos trust dscp

Trunk on 3850 connected to WAN router:

auto qos voip trust

[Mecalectro]

Port channel on 3850 connected to the 2960:
auto qos trust dscp

this configuration is applied to physical ports or port-channel ?

my configuration (show running-config) :

2960 port-channel on physical ports > 3850

 mls qos trust dscp
 auto qos voip trust

3850 port-channel on physical ports > 2960

auto qos trust
channel-group 2 mode on
service-policy input AutoQos-4.0-Trust-Cos-Input-Policy
service-policy output AutoQos-4.0-Output-Policy

"auto qos trust" is to apply before port-channel because after that it does not work.

3850 port > router voip

 srr-queue bandwidth share 10 10 60 20
 queue-set 2
 priority-queue out
 mls qos trust dscp
 auto qos voip trust
 no cdp enable

port ip phone > 2960

srr-queue bandwidth share 10 10 60 20
 queue-set 2
 priority-queue out
 mls qos trust dscp
 auto qos voip trust
 no cdp enable

---------------

For each port and physical port-channel on the 2960, I entered the following commands:

auto qos voip trust
mls qos trust dscp

by default "auto qos voip trust" applies "mls qos trust cos" then I reset the command "mls qos trust dscp".
my ip phone are set to "dscp".

[voip7372]

The QoS on the port channel ports goes on the physical ports.   

Per Cisco:  If you have EtherChannel ports configured on your switch, you must configure QoS classification, policing, mapping, and queueing on the individual physical ports that comprise the EtherChannel.

Regarding the config on an access port where a phone is plugged in, I would not use auto qos voip trust because the phone is at the edge and the qos voip trust is only intended for things like trunks where the traffic was already marked at the edge.  We use auto qos voip cisco-softphone because that will catch traffic for both a desk phone AND a Cisco IP communicator (if a PC is plugged in, using the softphone).  I confirmed this does indeed work for both a desk phone and softphone by making test calls when I was the only one at a new office and looking at the policy-map on the router to see if the traffic was being marked, and it was.

[GnetworkGnome]

I have found that if you have auto qos setup on the switch prior, and thus the policies are in-place, you can then apply the policies to the physical members of the port-channel.  So, I was able to first run an "auto qos trust" command on an unused interface, which generated the policies, and then I was able to apply those policies to the physical interfaces of the port-channel.

Before that, I would simply get the error: "AutoQoS Error: AutoQoS can not be configured on member port(s) of a port-channel," which I still get if I try the command.  Would this solve the problem, or do you need to have the actual "auto qos trust" command on the interface?

[voip7372]

I thought about that in the past too...if the policies were already there due to the auto qos command being run on a non-port channel port, could I manually assign those policies to the port channel port?   I assumed I could but I'm not familiar enough with it to know if it would work right so I didn't try it.

Anyway, I posted this (below) in another reply.  One of my colleagues said he discovered the 3850 didn't need QoS on those port channel ports and the markings would be honored if they were already present when the traffic arrived.  

"My colleague (the one that normally handles our QoS) told me he discovered the 3850 handles the traffic more like a router, so we removed the QoS entries on the port channels on the 2960 switches that link to the 3850 and on the 3850 there's no QoS entries at all.  So I'm told.  I haven't logged in to verify exactly how he has it configured now, but that's what he told me."

[GnetworkGnome]

Appreciate the response, I read that above and was hoping we could get some confirmation on this subject, so figured I would ask to see if I could generate more discussion.