CUBE connection to 6509 - interface setup

[gp1200x]

Setup - We have two CUBES each with a Verizon SIP connection at different points in our network. This setup has been in place for years and outgoing / incoming calls are split between them with each performing failover. The original setup was installed by Verizon engineers. We have portchannels to each  CUBE (on is attached to a 3750X stack and one to a 6509 VSS even though I believe only a single interface actually passes data with this setup at any time (not like a normal portchannel switch to switch setup when I view the interface stats).

While troubleshooting a CUBE issue I noticed that there are no settings on the interfaces connected to our CUBES. Going back to configs from years ago I also noticed there was nothing set so it is not like it was accidentally removed by me making changes over the years. In our switch to switch connections and routing connections and port connections we have QOS set on everything. I would think we should have had settings on the CUBE interfaces too.

My question is ..what settings should I use on the 6509 / 3750X interface connections to our CUBE ports? The ports on both the 6509 and 3750 are setup as switchports in a vlan in both CUBE connection scenarios. My main concern is incoming call traffic. Is the voice traffic coming in from the SIP and CUBE already marked or should I be setting a COS for it. Normally on switch connections to the 6509 we have  "mls qos trust cos" and on routed ports we have mls qos trust dscp". Is "mls qos trust cos" sufficient on the 6509 to CUBE switchports or should I be setting a COS value on the incoming voice packets from Verizon? 

[Jon Marshall]

I recommend you move this thread to IP Telephony where you should get help.

There is actually an experienced poster on these forums who works for Verizon so if you are lucky he may answer.

Jon

[gp1200x]

I have it posted over there for the last few days...so far no responses from anyone

[Jon Marshall · Accepted solution]

Okay, well firstly if the ports on the switches are not trunk ports there will be no CoS value because the CoS value is part of the 802.1q tag.

So nothing to trust.

If the Verizon device is setting DSCP which it may well be doing then you can trust DSCP although you need to make sure it is set to DSCP 46 which will be your EF class which I assume you use for VOIP.

Can't say whether it is or isn't but you could always SPAN one of the ports and use a packet capture tool to see if there are any DSCP markings in the packets.

I will send Deji (the Verizon guy) a private message with a link to this thread and hopefully he will have a look if he is around.

Sorry I can't be more help.

Jon

[gp1200x]

Thanks for helping on this and setting me straight again. I applied the mls qos trust dscp on our portchannels for the cubes and started reviewing all the 6509 VSS etherchannels and trunks to make sure the are set properly. 

Thanks for getting me an answer so quick!   These supportforums are extremely helpful.

[Ayodeji Okanlawon]

QoS is not my strongest point, however here is what we have on our 3750 that connects to one of our CUBEs.

interface GigabitEthernet2/0/10
 switchport access vlan 60
 switchport mode access
 mls qos trust dscp
 channel-group 10 mode on
 spanning-tree portfast

As for the 6509, I am not sure. I do have a colleague that I can reach out to, he is not around at the moment but hopefully before the end of the day, I will get something fro you

[Jon Marshall]

Hi Deji

Thanks for adding to this.

So from your configuration it looks like the Verizon device sets a DSCP value (presumably EF 46) so it is just a matter of trusting that on the switches.

Edit - it has sorted itself out and I can rate you now :)

Jon

[Ayodeji Okanlawon]

Yes Jon, voice traffic is marked as EF and the switch just trusts that. Thanks for the rating