Solved

Wireshark not seeing Cisco 7945G VOIP traffic as RTP

Posted on 2011-09-20
3
1,235 Views
Last Modified: 2012-08-13
I put the port on my Cisco 7945G phone into promiscuous mode so that my laptop see all traffic to/from the phone.  When I make a call I see a big stream of traffic from the phone to the voice gateway.  See example packet below.  This must be RTP traffic.  But wireshark is not classifying as such just seeing it as UDP traffic.   I am sure that these UDP packets are carrying voice.  When I go into Telephony/RTP Streams Wireshark says it sees no RTP streams.  Telephony/Voip Calls likewise yields nothing.  Why is wireshark not perceiving the voice traffic as expected?  Thanks!

336      09:56:36.912318      10.10.34.50      10.10.36.6      UDP      Source port: 28176  Destination port: 16486
0
Comment
Question by:amigan_99
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
3 Comments
 
LVL 20

Accepted Solution

by:
José Méndez earned 500 total points
ID: 36570298
Not sure why honestly, but you can right click > Decode as > RTP and it will clear the screen if there are no rtp packets, or show them all decoded if truly rtp.
0
 
LVL 1

Author Closing Comment

by:amigan_99
ID: 36570341
Yes!  So now wireshark sees those as G.729.  That reminds me I had put my own phone to G.729 as an experiment way back.  So if I change to G.711 - Telephony/Voice calls would let me listen to the stream?  Or is that another program?  A huge help.
0
 
LVL 20

Expert Comment

by:José Méndez
ID: 36570369
Yes, G.711 will allow wireshark to transcode the information. I think you can use Asterisk to transcode from G.729 to wav as explained here: http://www.experts-exchange.com/expertsZone.jsp

Regards,
0

Featured Post

Announcing the Most Valuable Experts of 2016

MVEs are more concerned with the satisfaction of those they help than with the considerable points they can earn. They are the types of people you feel privileged to call colleagues. Join us in honoring this amazing group of Experts.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Although VoiceOver IP has been around for a while, internet connections have only recently become fast enough to provide good call quality. Now, VoIP has become a real option for businesses looking at ways to improve their business model. In this ar…
As companies replace their old PBX phone systems with Unified IP Communications, many are finding out that legacy applications such as fax do not work well with VoIP. Fortunately, Cloud Faxing provides a cost-effective alternative that works over an…
In this video we outline the Physical Segments view of NetCrunch network monitor. By following this brief how-to video, you will be able to learn how NetCrunch visualizes your network, how granular is the information collected, as well as where to f…
Monitoring a network: how to monitor network services and why? Michael Kulchisky, MCSE, MCSA, MCP, VTSP, VSP, CCSP outlines the philosophy behind service monitoring and why a handshake validation is critical in network monitoring. Software utilized …

690 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question