Triple-Play Service Deployment

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Provisioning Tests
Purpose: To make sure that the IP phone is set up properly and can place/receive calls
Tests
1. Registration with Gatekeeper/proxy server - Ping
2. Place calls on and off the network
3. Trace the call route - Traceroute
4. Assess MOS/R-Factor for call quality
Troubleshooting Tests
Purpose: To determine the appropriate causes for poor call quality
Tests
1. Handset, volume, processor/DSP performance, mic/earpiece acoustics and echo canceller performance
2. TDM voice quality, echo
3. Network packet performance
a. Packet throughput
b. Packet loss
c. Packet delay/latency
d. Packet jitter
1. Call won’t connect
Likely trouble scenarios: Configuration errors, Packet Loss
Common Causes:
a. Registration problem with Call Manager
b. Gateway provisioning problem
2. Can make calls on, but not off the network
Common Causes:
a. Codec improperly configured
3. Call connects but can’t hear anything
4. Call connects but hear clicking/popping noise to the end user, garbled speech.
Likely trouble scenario: Packet Loss, Packet Jitter
Common Causes
a. Network Congestion
b. Buffer overruns in network components
c. Priority queuing and traffic shaping problems
d. Priority queuing and traffic shaping problems in combined VoIP / data networks
5. Call connects but then drops
Likely trouble scenario: Packet Loss
6. Call connects but hear over talk and line echo
Likely trouble scenario: Packet Delay
Common Causes:
a. Priority queuing and traffic shaping problems (CoS/QoS)
b. Choice of CODEC selection (packetization, buffering, compression)
c. Network congestion
Packet Loss
• Customer Experience – popping/clicks, dropped calls in extreme cases
• Best Test– exact measurement based on IP packet Sequence Stamp
Chapter 8: Troubleshooting VoIP