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the failure. After receiving the notification, a master/backup VRRP switchover is triggered, and
the backup device with the highest priority takes over traffic from the master device.
Networking Requirements
A VRRP-enabled AR2200-S can track a local forwarding interface connected to a network, but
not an interface along a network-side link connected to the local forwarding interface. If the
interface along the network-side link goes Down, the VRRP backup group cannot detect the
fault but continues to send packets along the link, causing user traffic loss.
To monitor the connectivity of the interface on the network-side link, an NQA ICMP test instance
can be configured on the NQA-supported AR2200-S and send test packets to the IP address.
The VRRP backup group can be associated with the NQA ICMP test instance. The NQA ICMP
test instance reports the link status to the VRRP backup group. This mechanism enables the
VRRP backup group to monitor the link connecting the master AR2200-S to the external
network. If the link fails, hosts on a LAN cannot access an external network through the master
router. NQA detects this fault and notifies VRRP of the fault. The VRRP backup group lowers
the master router's priority by a configured value. The backup router with the highest priority
will become the new master router and take over traffic. The process ensures that the
communication between the hosts and the external network is not interrupted. After the link
recovers, NQA detects the status change and instructs the VRRP backup group to restore the
priority of the previous master router.
On the network shown in
, two gateways form a VRRP backup group and work in
master/backup mode. The VRRP backup group needs to be associated with an NQA test instance
that monitors the IP address of Router C's interface connected to the network. If the interface
goes Down, NQA instructs VRRP to perform a master/backup VRRP switchover. After the
interface goes Up, traffic switches back to the previous master device.
Figure 2-6
Networking diagram for association between a VRRP backup group and an NQA
test instance
HostA
RouterA
RouterB
RouterC
RouterD
Internet
GE 2/0/0
192.168.1.1/24
VRRP Backup Group
Virtual IP Address:10.1.1.10
GE1/0/0
10.1.1.1/24
GE1/0/0
10.1.1.2/24
GE 1/0/0
192.168.1.2/24
GE2/0/0
20.1.1.1/24
Switch
NQA agent
GE 2/0/0
192.168.2.1/24
GE 1/0/0
192.168.2.2/24
Master
Backup
Huawei AR2200-S Series Enterprise Routers
Configuration Guide - Reliability
2 VRRP Configuration
Issue 01 (2012-01-06)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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