IP Phone Traffic Capture

[TheLaw]

We are sniffing an Avaya IP phone network (off of Definity R10 using Medpros and CLAN boards) and are wondering what sort of traffic we should expect to see from an initiated call. We are surprised to not find any rtp traffic and would like to confirm this (if so, then what *does* it use).

We are troubleshooting QoS issues and are looking at this from a Cisco point of view and are confused about the traffic we are seeing (well, in this case, what we are not seeing)

Your help is very much appreciated.

 

[BuckWeet]

Are you doing this on an ethernet switch? If so you just can't plug it in and expect to see the traffic, you have to configure the ethernet switch to be a SPAN port so you can monitor the traffic. Are you seeing any traffic coming from them?

BuckWeet

 

[TheLaw]

We're using a hub for that very reason. The Sniffer and IP Phone are both plugged into the hub (the only 2 devices) and that is plugged into the switch via uplink. The phone works wonderfully well - we just can't see any unicast traffic (only broadcasts)....

 

[BuckWeet]

Do you have some kind of filter setup on SNIFFER so that its only looking for certain kinds of traffic?

I kind of like the freebee called "ethereal"

http://www.ethereal.com/

Its pretty powerful for its cost. I'd give that a shot. Its also Q.931 aware.

FYI you could actually hook the phone back up to the switch, then just hook your PC into the PC port on the phone, since the phone has a hub in it, you'll see all the traffic anyways.. Thats how I usually do it..


BuckWeet

 

[TheLaw]

Thanks for the suggestions. We used both ethereal and sniffer. Did not think to use the built in hub (cisco stuff uses an internal switch so we figured the Avaya was the same). Thanks for the tip. I'll let you know how it goes.

 

[BuckWeet]

Heh, well, one thing to let you know.. Cisco says they have a switch, but if you hook your PC up to the phone and make a call, you will see all of the traffic actually.. So go figure..

I work on both MultiVantage and Cisco IP Telephony, each has its pluses and minuses...


BuckWeet

 

[Smudge1977]

Are you running your Voice on a different vLAN? I had stange results with hubs when I tried this and ended up mirroring a port on my switch. Stange but true!