Introduction; Overview Of Reliability Technologies; Indices Of Reliability - Huawei NetEngine80E Configuration Manual - Reliability

HUAWEI NetEngine80E/40E Router
Configuration Guide - Reliability

1.1 Introduction

Reliability is a technology that can shorten traffic interruption time on a network and improve
network performance.

1.1.1 Overview of Reliability Technologies

Reliability technologies are used to ensure high reliability on a network. Reliability technologies
cover system and hardware reliability design, software reliability design, reliability testing, and
IP network reliability design.
The reliability of a router involves the following aspects:
l
l
l
l
With the popularity of networks and diversification of applications, various value-added services
are deployed on networks. The bandwidth increases in index number. Therefore, even a short-
time interruption may impact a huge number of services critically and make an incredible loss.
For a fundamental network that bears services, its reliability is highlighted much more than ever.
This chapter focuses on reliability technologies applicable to the IP network over the Versatile
Routing Platform (NE80E/40E).

1.1.2 Indices of Reliability

Indices of reliability include MTTR, MTBF, and availability.
Generally, the reliability of a product or a system is evaluated based on two indices, namely,
Mean Time to Repair (MTTR) and Mean Time Between Failures (MTBF).
MTTR
The MTTR indicates the fault recovery capability. It is an index of maintainability. The MTTR
is the average time that a component or a device will take to recover from any failure. The MTTR,
in fact, is the fault-tolerance capability. In a broader sense, the MTTR also includes spare part
management and customer service. The MTTR is usually part of a maintenance contract.
The formula used to calculate the MTTR is as follows:
MTTR = Fault detection time + Board replacement time + System initialization time + Link
recovery time + Route coverage time + Forwarding recovery time
The smaller the addends are, the smaller the MTTR is and the higher the availability a device
offers.
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.
Issue 02 (2011-09-10)
System and hardware reliability design
Software reliability design
Test and authentication of reliability
IP network reliability design
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
1 Reliability Overview
2