H3C Technologies H3C MSR 50 - Manual (Page 35)

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Associating the Track module with an application
module
Associating Track with VRRP
VRRP is an error-tolerant protocol. It adds a group of routers that can act as network gateways to a VRRP
group, which forms a virtual router. Routers in the VRRP group elect the master acting as the gateway
according to their priorities. A router with a higher priority is more likely to become the master. The other
routers function as the backups. When the master fails, the backups in the VRRP group elect a new
gateway to undertake the responsibility of the failed master. This ensures that the hosts in the network
segment can uninterruptedly communicate with external networks.
When VRRP is operating in standard protocol mode or load balancing mode, associate the Track
module with the VRRP group to implement the following actions:
• Change the priority of a router according to the status of the uplink. If a fault occurs on the uplink
of the router, the VRRP group cannot be aware of the uplink failure. If the router is the master, hosts
in the LAN cannot access the external network. This problem can be solved by establishing a
Track-VRRP group association. Use the detection modules to monitor the status of the uplink of the
router and establish collaborations between the detection modules, Track module and VRRP. When
the uplink fails, the detection modules notify the Track module to change the status of the monitored
track entry to Negative, and the priority of the master decreases by a specific value. This allows a
higher priority router in the VRRP group to become the master, and maintains proper
communication between the hosts in the LAN and the external network.
• Monitor the master on a backup. If a fault occurs on the master, the backup working in switchover
mode will switch to the master immediately to maintain normal communication.
When VRRP is operating in load balancing mode, associate the Track module with the VRRP Virtual
Forwarder (VF) to implement the following functions:
• Change the priority of the active VF (AVF) according to its uplink state. When the uplink of the AVF
fails, the track entry changes to Negative state and the weight of the AVF decreases by a specific
value so that the VF with a higher priority becomes the new AVF to forward packets.
• Monitor the AVF status from the listening VF (LVF), which refers to the VF in listening state. When the
AVF fails, the LVF that is operating in switchover mode becomes the new AVF to ensure continuous
forwarding.
Follow these guidelines when you associate Track with VRRP group:
• VRRP tracking is not valid on an IP address owner. An IP address owner refers to a router when the
IP address of the virtual router is the IP address of an interface on the router in the VRRP group.
• When the status of the track entry changes from Negative to Positive or Invalid, the associated
router or VF restores its priority automatically.
• You can associate a nonexistent track entry with a VRRP group or VF. The association takes effect
only after you use the track command to create the track entry. For more information about VRRP,
see "Configuring VRRP."
To associate Track with VRRP group:
Step Command Remarks
34. Enter system view. system-view N/A