H3C Technologies H3C S12500-X Series Switches - Manual (Page 83)

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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 user-specified 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 operating in switchover
mode will switch to the master immediately to maintain normal communication.
Follow these guidelines when you associate Track with VRRP:
• 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 NotReady, the associated
router restores its priority automatically.
• You can associate a nonexistent track entry with a VRRP group. The association takes effect only
after you use the track command to create the track entry.
To associate Track with VRRP group:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter interface view.
interface interface-type
interface-number
N/A
3. Associate a track entry with a
VRRP group.
vrrp [ ipv6 ] vrid virtual-router-id
track track-entry-number [ reduced
priority-reduced | switchover ]
By default, no track entry is
specified for a VRRP group.
Associating Track with static routing
A static route is a manually configured route. With a static route configured, packets to the specified
destination are forwarded through the path specified by the administrator. For more information about
static route configuration, see Layer 3—IP Routing Configuration Guide.
The disadvantage of using static routes is that they cannot adapt to network topology changes. Faults or
topological changes in the network can make the routes unreachable, causing network breaks.
To prevent this problem, configure another route to back up the static route. When the static route is
reachable, packets are forwarded through the static route. When the static route is unreachable, packets
are forwarded through the backup route, avoiding network breaks and enhancing network reliability.
To check the accessibility of a static route in real time, establish an association between Track and the
static route.
If you specify the next hop but not the egress interface when configuring a static route, you can establish
collaborations among the static route, the Track module, and detection modules. This enables you to
check the accessibility of the static route by the status of the track entry.
• The Positive state of the track entry shows that the next hop of the static route is reachable, and that
the configured static route is valid.
• The Negative state of the track entry shows that the next hop of the static route is not reachable, and
that the configured static route is invalid.