Frequently Asked Questions - Vodavi XTS-IP Installation Manual

VoIP Maintenance and Troubleshooting

Frequently Asked Questions

Can a wireless connection be used between sites?
Wireless connections (microwave or 802.11b) typically do not meet the recommended
100 mbps connection speeds, but have been shown to be quite capable for VoIP connectivity.
The only considerations should be the affects the link has on latency, jitter, and QoS. These are
the same considerations for any IP connection.
Can Network Address Translation be used with the VoIP card?
Network Address Translation (NAT) is a function of a router. The original implementations of
NAT did not take into account the streaming functions of H.323 or other similar protocols. Thus,
NAT prevents VoIP calls from establishing a voice connection. It is recommended that you
avoid the use of NAT completely.
What factors affect voice quality?
The major factors for voice quality are latency, jitter, and wiring.
Latency is increased if the total available bandwidth is lower. In the case of a 512k connection
that has 400k of data running through it, the latency is greatly increased than when the 512k
connection has no data running through it.
Jitter is the fluctuation in latency. This is generally seen when a large amount of traffic is creating
large fluctuations in utilized bandwidth (utilization). A network that exhibits latency of 20ms
followed by 120ms has a very difficult jitter to compensate for in the software voice processing.
A jitter buffer is used to minimize this affect.
Category 5 or higher cable must be used with RJ-45 connectors.
How is the VoIP card programmed?
Standard Vodavi flash programming is used to program the VoIP card. Programming is stored
on the MPB (Master Processor Board) and read by the VoIP card upon reset of the system or the
VoIP card.
XTS-IP - Installation Manual
Chapter 4 - Maintenance and Troubleshooting
4-59
December 2005