Nortel Networks NN43001-504 manual Voice-quality issues

Troubleshooting 197

Voice-quality issues

The transport, or IP data network, are the most likely causes of voice-quality issues. In some circumstances, product issues (such as echo or Digital Signal Processor (DSP) errors) can cause problems with voice quality. The data network does not introduce echo into a conversation, but it can enhance existing echo.

In a converged environment, voice competes with data traffic for bandwidth and processor time. As a result, the IP data network must be optimized for efficient processing of the real-time voice packets.

Table 25

Typical voice quality issues

Issue	Type of	Check for
	issue
Choppy voice	Network	Network delay caused by:
	(usually)	Excessive intermittent end-to-end round-trip
		delay
		Congestion
		Queuing
		Network configuration errors
		Packet loss caused by:
		Physical errors in data network
		Network configuration errors
First or last part	Product	Incorrect Voice Activity Detection (VAD)
of word syllables	(usually)	configuration
missing		OR
		Incorrect AP configuration (if the issue occurs
		only during roaming)
Clicks or pops		Packet loss, cause depends on the codec
heard during
conversation
One-way speech	Network	IP routing issues
path		Congestion issues
	Product	Incorrect configuration
Voice delay	Network	Excessive network delay
(users talk over
each other)
Echo	Network	Data network can enhance echo
	Product
	(primarily)

Nortel Communication Server 1000

WLAN IP Telephony Installation and Commissioning

NN43001-504 01.02 Standard

Release 5.0 15 June 2007

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