Reliability And Availability - Avaya S8100 Series Manual

Introduction

Reliability and availability

The reliability of a telecommunications system is defined by the extent of duplication of certain
components. The traditional standard, high, and critical reliability levels apply to the
pre-Linux-based switches. For Linux-based media servers, the standard reliability level is
expanded to include simplex for S8500 media servers and duplex for S8700-Series media
servers.
The availability of a telecommunications system is the time the system is ready and able to
process calls as a percentage of the scheduled time. Availability depends on reliability.
Release 3.1 introduced the ability to combine types of port network connectivity (PNC) and to
apply reliability designations separately to the IP-PNC portion and the fiber-PNC portion of the
system. The reliability level is defined per port network for the IP-PNC portion and collectively
for the fiber-PNC portion. Therefore, combined PNC systems can have combined reliabilities.
For pure IP-PNC configurations, the reliability designation is also per port network.
Release 3.1 introduced the ability to add, to an IP-PNC port network, duplicated bearer
reliability, in addition to duplicated control reliability, which together constitute critical reliability.
Note:
Duplicated bearer can be implemented without duplicated control for both the
Note:
S8500 and S8700-series Media Servers. Unlike previous releases, duplicated
control is not a prerequisite for duplicated bearer.
Table 1 and Table 2
Reliability definitions for pre-Linux-based CSI switch are unchanged.
52 Upgrading, Migrating, and Converting Media Servers and Gateways
summarize reliability levels for systems with Linux-based media servers.