Dell Force10 MXL Blade MXL 10/40GbE Switch IO Module Configuration Guide - Page 637

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. Table 38-1. Recommended VRRP Advertise Intervals Total VRRP Groups Less than 250 Between 250 and 450 Between 450 and 600 Between 600 and 800 Between 800 and 1000 Between 1000 and 1200 Between 1200 and 1500 Recommended Advertise Interval Groups/Interface 1 second 255 2 - 3 seconds 255 3 - 4 seconds 255 4 seconds 255 5 seconds 255 7 seconds 255 8 seconds 255 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. 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. Virtual Router Redundancy Protocol (VRRP) | 635