How to Get Packet Capture from VXML Gateway for Signal and Voice Analysis

Introduction

This document describes how to get a packet capture (pcap) from a VXML Gateway for signal and voice analysis.

Prerequisites

Requirements

Cisco recommends that you have knowledge of these topics:

• Unified Customer Voice Portal (CVP)

• Voice Extensible Markup Language Gateway (VXML GW) 

• Whireshark tool

Components Used

This document is not restricted to specific software and hardware versions.

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, ensure that you understand the potential impact of any command.

Take Packet Capture on VXML Gateway

You can get a pcap to check signaling and media from the Cisco VXML GW with this procedure for interface g0/0. You need to change inteface name in the command to the appropriate one.

conf t 
ip traffic profile test mode capture 
bidirectional 
exit

int g0/0
ip traffic apply test size 20000000 
end 

traffic int g0/0 clear 
traffic int g0/0 start 

VXML gateway capturing traffic, so make a test call and quickly stop the packet capture.

traffic int g0/0 stop

In order to copy the pcap to an TFTP server type this command.

traffic int g0/0 copy tftp://x.x.x.x/g00.pcap 

In order to copy the pcap to an FTP server type this command.

traffic int g0/0copy ftp://username:password@x.x.x.x/g00.pcap

The screenshot shows the pcap file port1.pcap opened with Wireshark tool.

Verify

In order to verify that the packet capture is valid use this procedure.

Step 1. Filter sip signalling. 

Enter sip keyword in Filter textbox.

Step 2. Open the RTP streams with Wireshark Player.

• Navigate to Telephony - Voip Calls
• Choose the call in question 
• Select Player

Step 3. Click Decode.

Step 4. Playback the recording.

In order to playback the recorded conversation select the decoded graph for the call in question and select Play.

The procedure described can be used to troubleshoot issues with audio quality, one-way audio or dead air conditions.

These debug commands can be typed on the VXML gateway for additional diagnosis.

debug ccsip mess
debug ccsip error
debug voip ccapi inout 
debug voip dialpeer inout
debug http client all
debug voip application script
debug voip application vxml
debug voip rtp session named-events
debug voip rtp sess nse
debug voip rtp