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Alteon OS Application Guide
230
Chapter 13: High Availability 42C4911, January 2007
Alteon OS extensions to VRRP
This section describes the following VRRP enhancements that are implemented in Alteon OS:
Tracking VRRP Router Priority
Tracking VRRP Router Priority
Alteon OS supports a tracking function that dynamically modifies the priority of a VRRP
router, based on its current state. The objective of tracking is to have, whenever possible, the
master bidding processes for various virtual routers in a LAN converge on the same switch.
Tracking ensures that the selected switch is the one that offers optimal network performance.
For tracking to have any effect on virtual router operation, pre-emption must be enabled.
Alteon OS can track the attributes listed in Table 13-1:
Each tracked parameter has a user-configurable weight associated with it. As the count associ-
ated with each tracked item increases (or decreases), so does the VRRP router's priority, sub-
ject to the weighting associated with each tracked item. If the priority level of a standby is
greater than that of the current master, then the standby can assume the role of the master.
See “Configuring the Switch for Tracking” on page 231 for an example on how to configure
the switch for tracking VRRP priority.
Table 13-1 VRRP Tracking Parameters
Parameter Description
Number of IP interfaces on the switch that
are active (“up”)
/cfg/l3/vrrp/track/ifs
Helps elect the virtual routers with the most available
routes as the master. (An IP interface is considered active
when there is at least one active port on the same VLAN.)
This parameter influences the VRRP router's priority in
virtual interface routers.
Number of active ports on the same VLAN
/cfg/l3/vrrp/track/ports
Helps elect the virtual routers with the most available
ports as the master. This parameter influences the VRRP
router's priority in virtual interface routers.
Note: In a hot-standby configuration, only external ports
are tracked.
Number of virtual routers in master mode
on the switch
/cfg/l3/vrrp/track/vr
Useful for ensuring that traffic for any particular client/
server pair is handled by the same switch, increasing rout-
ing efficiency. This parameter influences the VRRP
router's priority in virtual interface routers.