Overview of Voice over IP (VoIP)
More information about SNMP and MIBs can be found in the IETF references listed in Chapter 1, Related Documents. Appendix A of this LAN Administration Guide lists the Custom MIB, which is also available for download in *.txt format on the Avaya support website.
Network Assessment
The current technology allows optimum network configurations to deliver VoIP with perceived voice quality close to that of the Public Switched Telephone Network (PSTN). Not every network is able to take advantage of packet voice transmissions. Some data networks have insufficient residual capacity for even compressed voice traffic. In addition, the usual approach to developing data networks by integrating products from many vendors makes it necessary to test the components for compatibility with Voice over IP traffic.
It is assumed that your organization has performed a network assessment (with or without the assistance of Avaya) before attempting to install Voice over IP, in order to have a high degree of confidence that the existing data network has the capacity to carry voice packet traffic and is compatible with the required technology.
A network assessment would include a determination of the following:
■A network audit to review existing equipment and evaluate its capabilities, including its ability to meet planned voice and data needs.
■A determination of network objectives, including the dominant traffic type, choice of technologies, and setting voice quality objectives.
The assessment should leave you confident that the implemented network will have the capacity for the foreseen data and voice traffic, and can support H.323, DHCP, TFTP, and jitter buffers in H.323 applications.
It is important to distinguish between compliance with the minimal VoIP standards and support for QoS which is needed to run VoIP on your configuration.
Suggestions for Installation and Configuration
Reliability and Performance
There is a cost/performance
The reliability and performance of the traditional PBX systems have been very high. Although much of the LAN is outside of the control of the PBX, there are several points to consider which enhance the reliability and performance of the IP Telephone network.
Network Assessment
