QOS and Cisco SG200

[jeepinbob]

I have a set up with 15 sites connected via an MPLS network. The network was never set up with QOS. We use VOIP for 4 digit dialing from site to site and for VM Pro to the sites. All sites use digital phones.

I am using wire shark to grab packets from the port connected to the router. and I am not seeing DSCP 46 tags on packets going out from the Solution (most packets going to Solution have the DSCP 46 flag). I am also only seeing about a dozen packets (from a 15 MB packet capture) going to or from the phone switch. If I understand the IP Office, when a 4 digit call (VOIP) is placed, the Solution handles the connection and then the voice traffic travels directly from phone switch to phone switch. So I should see a lot more packets going to the phone switch.

Also, I am trying to get QOS on the switch between the router and the phone switch in the main office (where the VM Pro resides with Avaya Solution). The SG200 is configured for DSCP 46 traffic to be assigned to queue 4 (highest priority) and queue4 has strict precedence. I have set the two counters to show queue 4 traffic for both the port going to the router (that goes to the 14 other sites) and the port that goes to another SG200 switch that the IP Office is plugged into. Neither counter is showing queue 4 traffic even while I am on a call from one of the sites to the main office.

I apologize if this is not clear, but I am a bit confused at what I am seeing and not sure where to go from here.

Bob

 

[amriddle01]

If the call is established and you can actually hear sound both ways then you know packets are traversing the link, if you can't see them then you aren't monitoring correctly/at the correct point

 

[fieldtechonIR]

It only travels from IPO to IPO if DMP is turned off. If DMP is on then once the call is set up the audio travels from phone to phone if your routing is correct.

 

[hairlessupportmonkey]

on the sg200 you should be able to mirror a port that you want to monitor. you will get much better results if you emulate being plugged into the port. (port mirror)

here is an article on QoS for voice on the SG200 series.

http://www.mcbsys.com/blog/2011/05/basic-qos-setup-on-a-cisco-sg-200-switch/

ACSS - SME
General Geek

 

[mattKnight]

Depending on how the Lan is configured, Dscp markings can be stripped.

Investigate the cisco command 'qos trust dscp'

Take Care

Matt
I have always wished that my computer would be as easy to use as my telephone.
My wish has come true. I no longer know how to use my telephone.

 

[jeepinbob]

hairlessupportmonkey:
I have used that article and believe I have all ports set to use strict priority with DSCP46 using queue 4 I have mirrored the port that goes to the router (rest of the sites) and I get only a dozen or two packets going to the local IP office, but many going to the solution. This is out of a 15 Mb packet capture.

I have also set the QOS counters to count queue4 packets and even though I have traffic passing both ports (router and IP office) with DSCP46 set, the counters don't seem to go up. After two hours I have 311 packets in queue4. I know there is a LOT more voip traffic passing through.


mattKnight:
Thanks for the heads up but so far I have not found this in any of the routers. I do have a few more to check though.

Thank you both for the input.

Bob

 

[amriddle01]

fieldtechonIR , not with digital phones it doesn't

 

[amriddle01]

What is this "solution" you keep referring to?

 

[amriddle01]

P.s This doc may help, old but still....

 

[hairlessupportmonkey]

If its MPLS, why not just create a vlan across the network for voice?

ACSS - SME
General Geek

 

[fieldtechonIR]

I missed the digital phone part. Yes this is true.

 

[jeepinbob]

hairlessupportmonkey,
The MPLS is going away and I don't think that is where my problems are. It is managed by ATT and they supposedly have QOS set up on it. The coming network will be a layer 2 setup. Kinda like a virtual switch.

amriddle01,
Solution is a linux box (virtual) running VMPro and the IP Office software server software. It is kinda like the main hub. Also the phones to the IP Office are digital, but we have SCN lines from each site to the "Solution". So as I understand it should be IP from site to site. Either way, what is DMP and where do I find it?

Thanks as always for the input,
Bob