Avaya 555-245-600 manual Jitter, Packet loss maximum packet/ frame loss between endpoints

IP Telephony network engineering overview

trunk that links the west coast of the United States to India could add a fixed delay of 150 milliseconds (ms) into the overall delay budget.

Perfectly acceptable voice quality is attainable, but will not be “toll” quality. Therefore, Avaya presents a tiered choice of elements that make up the requirements.

The critical objective factors in assessing IP Telephony quality are delay, jitter, and packet loss. To ensure good and consistent levels of voice quality, Table 49: Factors that affect voice quality on page 286 lists Avaya’s suggested network requirements. These requirements are true for both LAN only and for LAN and WAN connections.

Table 49: Factors that affect voice quality

Network factor	Measurement1
Delay		● A delay of 80 ms or less can, but may not, yield the best
(one-way between		quality.
endpoints)		● A delay of 80 ms to 180 ms can yield
		business-communication quality. Business-communication
		quality is much better than cell-phone quality, and is
		well-suited for the majority of businesses.2
		● Delays that exceed 180 ms might still be quite acceptable
		depending on customer expectations, analog trunks used,
		codec type, and so on.
Jitter		● 20 ms, or less than half the sample size, for the best quality.
(variability of the delay		Note:
between endpoints)
	Note:	This value has some latitude, depending on the
		type of service that the jitter buffer has in

relationship to other router buffers, the packet size used, and so on.

Packet loss (maximum packet/ frame loss between endpoints)

●<1% can yield the best quality, depending on many factors.

●<3% should give business-communications quality, which is much better than cell-phone quality.2

●>3% might be acceptable for voice, but might interfere with signaling.

1.All measurement values are between endpoints because this document assumes that IP Telephony is not yet implemented. All values therefore reflect the performance of the network without endpoint consideration.

2.Also, “business-communication quality” is defined as less than toll quality, but much better than cell-phone quality.

For more information see Voice quality network requirements.

286 Avaya Application Solutions IP Telephony Deployment Guide