Please make sure your device is rooted before following these steps.
1. Start adb in root mode by entering the following command
3. Push tcpdump to the device.
adb push tcpdump-arm /data/local/
4. Make sure correct permission is set for tcpdump.
adb shell chmod 777 /data/local/tcpdump-arm
5. Start capturing the network packets. Replace any with your interface name. In my case it was wlan0.
adb shell /data/local/tcpdump-arm -i any -p -s 0 -w /data/local/captured.pcap
6. Once the network packets are captured we can copy that back to your machine to view it in wireshark.
adb pull /data/local/captured.pcap
7. View the SIP packets in wireshark using the view filter.
Note: Wireshark can be downloaded from http://www.wireshark.org/download.html