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MTBF
The MTBF indicates the probability of faults. It is an index of reliability. The MTBF is the
predicted elapsed time between inherent failures of a system during operation, usually in hours.
Availability
The availability identifies the utility of a system. You can improve the device availability by
increasing the MTBF and decreasing the MTTR.
In the telecommunication industry, 99.999% availability means that service interruption caused
by device failures must be less than 5 minutes each year.
In actual networking, network faults and service interruption are inevitable. Therefore, providing
technologies to enable device to recover from failures rapidly becomes very important. Such
technologies can improve device availability by reducing MTTR.
1.1.3 Levels of Reliability Requirements
The objective and implementation method of the reliability vary with the level of reliability
requirements.
lists three requirement levels and describes their objectives and implementation
methods.
Table 1-1
Levels of reliability requirements
Level
Objective
Implementation Method
1
Less faults in the
software and hardware
of a system
l
Hardware: simplified design, standardized circuits,
reliable application of components, reliability
control over purchased components, reliable
manufacture, environment adaptability, and
reliability testing (HALT/HASS)
l
Software: checklist for the software reliability design
2
No impact on a system
when a default occurs
l
Redundancy design
l
Switchover policy
l
High availability of switchover
3
Rapid recovery from a
fault that affects the
system
l
Fault detection
l
Fault diagnosis
l
Fault isolation
l
Fault recovery
1.1.4 Principles for High-Reliablity IP Networking
Technologies for reliable networking cover the hierarchy networking, redundancy technology,
and load balancing technology.
The principles for high-reliablity IP networking are as follows:
HUAWEI NetEngine80E/40E Router
Configuration Guide - Reliability
1 Reliability Overview
Issue 02 (2014-09-30)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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