/mcp3640−6# DSP VOICE TX STATISTICS Tx Vox/Fax Pkts: 209, Tx Sig Pkts: 0, Tx Comfort Pkts: 11 Tx Dur(ms): 337420, Tx Vox Dur(ms): 416, Tx Fax Dur(ms): 0 DSP VOICE RX STATISTICS Rx Vox/Fax Pkts: 16843, Rx Signal Pkts: 0, Rx Comfort Pkts: 1 Rx Dur(ms): 337420, Rx Vox Dur(ms): 335920, Rx Fax Dur(ms): 0 Rx Non−seq Pkts: 0, Rx Bad Hdr Pkts: 0 Rx Early Pkts: 3, Rx Late Pkts: 26 DSP VOICE VP_DELAY STATISTICS Clk Offset(ms): 0, Rx Delay Est(ms): 72 Rx Delay Lo Water Mark(ms): 51, Rx Delay Hi Water Mark(ms): 161 DSP VOICE VP_ERROR STATISTICS Predict Conceal(ms): 510, Interpolate Conceal(ms): 0 Silence Conceal(ms): 70, Retroact Mem Update(ms): 0 Buf Overflow Discard(ms): 910, Talkspurt Endpoint Detect Err: 0 DSP LEVELS TDM Bus Levels(dBm0): Rx −51.5 from PBX/Phone, Tx −44.1 to PBX/Phone TDM ACOM Levels(dBm0): +2.0, TDM ERL Level(dBm0): +11.9 TDM Bgd Levels(dBm0): −61.3, with activity being voice DSP VOICE ERROR STATISTICS Rx Pkt Drops(Invalid Header): 0, Tx Pkt Drops(HPI SAM Overflow): 0 Configure Jitter Buffer on a Gateway The QoS guidelines covered in this document take care of the choppy or deteriorated voice quality issue. The configuration of playout−delay buffer is a workaround for improper QoS implementation in the network. Only use this as a stop−gap fix or as a tool for troubleshooting and narrowing down of the jitter problems introduced in the network. Playout−delay Mode The jitter buffer is configured for either fixed mode or adaptive mode. Under the adaptive mode, the gateway allows you to configure a minimum value for the jitter buffer, a maximum value, and a nominal value. The jitter buffer expects the packets to arrive within the nominal value range. The nominal value has to be either equal to or more than the minimum, and equal to or less than the maximum. The buffer expands up to the maximum value configured. This can extend up to 1700 msec. One issue with configuring high maximum value is the introduction of end−to−end delay. Choose the value of maximum playout−delay such that it does not introduce unwanted delay in the network. This output is an example of the jitter buffer configured for adaptive mode: 3640−6# 3640−6#configure terminal Enter configuration commands, one per line. End with CNTL/Z. 3640−6(config)#voice−port 3/0/0 3640−6(config−voiceport)#playout−delay mode adaptive 3640−6(config−voiceport)#playout−delay maximum 400 3640−6(config−voiceport)#playout−delay nominal 70 3640−6(config−voiceport)#playout−delay minimum low 3640−6(config−voiceport)#^Z 3640−6# 3640−6# 3640−6#show run | begin 3/0/0 voice−port 3/0/0 playout−delay maximum 400 playout−delay nominal 70 playout−delay minimum low playout−delay mode adaptive ! Under the fixed mode, the gateway looks at the configured value for nominal. Although it allows you to