Virtual Router Redundancy Protocol (VRRP) | 635
VRRP Benefits
With VRRP configured on a network, end-station connectivity to the network is not subject to a single
point-of-failure. End-station connections to the network are redundant and they are not dependent on
internal gateway protocol (IGP) to converge or update routing tables.
VRRP Implementation
The MXL 10/40GbE Switch supports a total of 2000 VRRP groups on a switch and 255 VRRP groups per
interface (Table 38-1).
Within a single VRRP group, up to 12 virtual IP addresses are supported. Virtual IP addresses can belong
to the primary or secondary IP address’ subnet configured on the interface. You can ping all the virtual IP
addresses configured on the Master VRRP router from anywhere in the local subnet.
Default VRRP settings may affect the maximum number of groups that can be configured and work
efficiently, as a result of hardware throttling VRRP advertisement packets reaching the CP on the MXL
Switch.To avoid throttling VRRP advertisement packets, Dell Force10 recommends increasing the VRRP
advertisement interval to a value higher than the default value of 1 second. Table 38-1 list the
recommendations.
The recommendations in Table 38-1 may vary depending on various factors like address resolution
protocol (ARP) broadcasts, IP broadcasts, or spanning tree protocol (STP) before changing the
advertisement interval. When the number of packets processed by the CP processor increases or decreases
based on the dynamics of the network, the advertisement intervals in may increase or decrease accordingly.
Table 38-1. Recommended VRRP Advertise Intervals
Total VRRP Groups
Recommended Advertise Interval Groups/Interface
Less than 250 1 second 255
Between 250 and 450 2 - 3 seconds 255
Between 450 and 600 3 - 4 seconds 255
Between 600 and 800 4 seconds 255
Between 800 and 1000 5 seconds 255
Between 1000 and 1200 7 seconds 255
Between 1200 and 1500 8 seconds 255
CAUTION: Increasing the advertisement interval increases the VRRP Master dead interval, resulting in an
increased failover time for Master/Backup election. Take extra caution when increasing the advertisement
interval, as the increased dead interval may cause packets to be dropped during that switch-over time.
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