Avaya P333R-LB Manuel D’Utilisation

Chapter 14

Load Balancing in the P333R-LB

14

Avaya 

P333R-LB User’s Guide

When Firewall 2 is removed from the group, the list of available firewalls is 
readjusted, causing a lack of persistency. However, if Firewall 2 becomes 
operational again, the list of available firewalls is restored to its original order, and 
persistency is recovered, making Hash a predictable metric.

MinMiss Hash

The metric parameter for MinMiss Hash is: Source IP, Destination IP.
MinMiss Hash distributes sessions to firewalls in the same way as the Hash metric. 
However, MinMiss Hash sustains persistency even when a server is removed from 
the firewall group. When a firewall fails or is removed, the positions of the other 
firewalls in the list do not change. Instead, the remaining firewalls are redistributed 
to the list entries freed by the failing firewall. The following figure illustrates how 
persistency is maintained even though a firewall becomes non-operational.

When Firewall 2 is removed from the group, the list of available firewalls is not 
readjusted. Only the list entries that are now empty are replaced with other 
available firewalls. Therefore, persistency is sustained for all available firewalls. If 
Firewall 2 becomes operational again, the list of available firewalls is recalculated so 
that the smallest number of firewalls is affected. However, the list of firewalls is not 

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