Blade ICE G8124-E Manuale Utente

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BLADEOS 6.5.2 Application Guide
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  Chapter 24: Virtual Router Redundancy Protocol
BMD00220, October 2010
BLADEOS Extensions to VRRP
This section describes VRRP enhancements that are implemented in BLADEOS.
BLADEOS 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, preemption must be enabled.
BLADEOS can track the attributes listed in 
 (Router VRRP mode):
Each tracked parameter has a user-configurable weight associated with it. As the count associated 
with each tracked item increases (or decreases), so does the VRRP router's priority, subject 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.
 for an example on how to configure the 
switch for tracking VRRP priority.
Table 23   
VRRP Tracking Parameters
Parameter
Description
Number of IP interfaces on the switch 
that are active (“up”)
tracking-priority-increment
interfaces
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
tracking-priority-increment
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.
Number of virtual routers in master mode 
on the switch
tracking-priority-increment
virtual-routers
Useful for ensuring that traffic for any particular 
client/server pair is handled by the same switch, 
increasing routing efficiency. This parameter 
influences the VRRP router's priority in virtual 
interface routers.