Brocade BigIron RX Series Configuration Guide - Manual (Page 511)

BigIron RX Series Configuration Guide 433
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Overview of Virtual Switch Redundancy Protocol (VSRP)
15
You can reduce the sensitivity of a VSRP device to failover by increasing its configured VSRP
priority. For example, you can increase the configured priority of the VSRP device on the left in
Figure 77 to 150. In this case, failure of a single link does not cause failover. The link failure caused
the priority to be reduced to 100, which is still equal to the priority of the other device. This is shown
in
Figure 78 .
FIGURE 78 VSRP priority bias
Track ports
Optionally, you can configure track ports to be included during VSRP priority calculation. In VSRP, a
track port is a port that is not a member of the VRID’s VLAN, but whose state is nonetheless
considered when the priority is calculated. Typically, a track port represents the exit side of traffic
received on the VRID ports. By default, no track ports are configured.
When you configure a track port, you assign a priority value to the port. If the port goes down, VSRP
subtracts the track port’s priority value from the configured VSRP priority. For example, if the you
configure a track port with priority 20 and the configured VSRP priority is 100, the software
subtracts 20 from 100 if the track port goes down, resulting in a VSRP priority of 80. The new
priority value is used when calculating the VSRP priority.
Figure 79 shows an example.
X
VSRP
Master
VSRP
Backup optional link
VSRP
Aware
VSRP
Aware
VSRP
Aware
F F F B B B
Configured priority = 150
Actual priority = 150 * (2/3) = 100 Configured priority = 100
Actual priority = 100 * (3/3) = 100
Link down