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12.1 Configuration Overview
This section provides the necessary background for HA configuration, including HA
introduction, HA backup features and scenarios, and HA service features.
12.1.1 HA Overview
HA implements data backup between VSUF-40/80/160 service processing boards (service board
for short) of CGN devices. HA prevents network or service interruption caused by the failure of
a single device or link. This feature improves device availability and service reliability and
ensures stable operation of the carrier network.
Background
As the number of Internet users keeps increasing and mobile broadband and the Internet of
Things rapidly develop, IPv4 address shortage has become an increasingly serious problem.
IPv6 can solve the problem of IPv4 address shortage, but IPv4 networks will not be replaced by
IPv6 networks in a short time because a large number of IPv4 services are deployed on the
Internet. A reasonable approach is to gradually deploy IPv6 without affecting existing IPv4
services. When IPv6 is widely used, the IPv4 Internet can be replaced by a pure IPv6 Internet.
IPv4 and IPv6 will coexist for a long time before a pure IPv6 Internet is built.
During transition from IPv4 to IPv6, NAT can mitigate IPv4 address shortage. Traditional NAT
is deployed on the CPE to translate addresses for a few users. CGN is deployed on the carrier
network to translate addresses for a large number of users. Therefore, CGN devices must have
higher capacities, performance, and reliability than the traditional NAT devices.
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CGN devices can translate between various network addresses, for example, between IPv4
private addresses, between IPv4 private and public addresses, and between IPv4 addresses
and IPv6 addresses. Some CGN devices also provide the tunnel function.
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The CGN function can be provided by an independent CGN device and or a CGN card
installed on another device. A CGN card can be installed on a broadband remote access
server (BRAS) so that one physical device can provide the BRAS and CGN functions.
CGN devices are deployed in centralized or distributed mode, as shown in the following figure.
HUAWEI NetEngine80E/40E Router
Configuration Guide - Reliability
12 CGN Backing Up HA Configuration
Issue 02 (2014-09-30)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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