NOTE
In load balancing mode, an interface on a single Router can have different priorities if they join
multiple VRRP backup groups.
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Smooth VRRP switching
On a network with a VRRP backup group, during an AMB/SMB switchover, the master
Router cannot send VRRP Advertisement packets to backup Routers. The backup
Routers consider the master Router faulty because they do not receive VRRP
Advertisement packets. As a result, a backup Router with a higher priority than others
preempts the Master state. If an AMB/SMB switchover is complete, and the preemption
mode is enabled, the original master Router preempts the master state again because its
priority is higher than the priorities of other Routers in the VRRP backup group. This causes
the unstable VRRP status and frequent link switching. As a result, user packets are dropped.
Smooth VRRP switching prevents the preceding problems. The master Router will save
the current interval at which VRRP Advertisement packets are sent and set the smooth
VRRP switching time as a new interval. During smooth VRRP switching, the master
Router broadcasts a VRRP Advertisement packet at the new interval. After receiving the
packet, the backup Routers learn the new interval value and reset their timeout timer for
receiving packets. This ensures stable VRRP backup group operation and prevents user
packet loss during the AMB/SMB switchover and data smoothing.
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Pinging the virtual IP address
Pinging the virtual IP address can be enabled or disabled on VRRP-enabled routers.The
router allows user devices to ping a virtual IP address to serve the following purposes:
–
Monitors the operating status of the master router in a VRRP IPv4 backup group.
–
Monitors communication between a user device and a network connected by a default
gateway using the virtual IP address.
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VRRP authentication
Authentication modes and keys can be set based on network security requirements and
these settings are carried in the headers of VRRP Advertisement packets.
On a secure network, default values are used. By default, the router does not authenticate
any VRRP Advertisement packets. Therefore, there is no need to set an authentication key.
On a vulnerable network, VRRP supports the following authentication modes:
–
Simple authentication: A key is a string of 1 to 8 characters.
–
Message Digest 5 (MD5) authentication: A simple key is a string of 1 to 8 characters.
A ciphertext key is 24 or 32 characters long.
4.1.2 VRRP Features That the NE80E/40E Supports
This section describes logical VRRP configurations that the NE80E/40E supports. The
information will help you complete configuration tasks quickly and efficiently.
VRRP Functions That the NE80E/40E Supports
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Basic VRRP functions are configured. VRRP-enabled NE80E/40Es work either in master/
backup mode to back up data or in load balancing mode to equally distribute data.
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An mVRRP backup group is configured, and VRRP backup groups are bound to the
mVRRP backup group. The mVRRP backup group sends VRRP Advertisement packets to
determine the master and backup status. This prevents the increasing number of VRRP
HUAWEI NetEngine80E/40E Router
Configuration Guide - Reliability
4 VRRP Configuration
Issue 02 (2014-09-30)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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