Study of network instability in VRRP and HSRP sub second tier timer implementation

  • Author(s) / Creator(s)
  • Network instability is a big concern when implementing sub-second timers. Implementing First Hop Redundancy Protocol (FHRP) sub-second advertisement interval can increase the potential for network instability. In this paper we
    studied the impact of sub-second timer implementation on network stability for fast failure detection and failover of two FHRP - VRRP (Virtual Router Redundancy Protocol) and HSRP (Hot Standby Redundancy Protocol). The goal of
    our research was achieved by simulating a production network, and implementing sub-second timers under induced process switched network traffic while varying timer values- increasing values set progressively from 50msec through 999msec- and varying the target of the induced network traffic between different interfaces on the active/master and backup/standby routers. From the results of our experiments, we conclude that sub-second timer implementation can adversely impact network stability given two conditions. When either the input queue of the interface on the backup/standby router used for keepalive message reception overflows and/or the output queue of the interface on active/master interface used for keepalive message forwarding overflows.

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  • Type of Item
    Research Material
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  • License
    Attribution-NonCommercial 4.0 International