Avaya P333R-LB Application Manual page 6

The Load Balancing Process
The P333R-LB selects the best available physical
server upon receiving a new session request based
on the following:
• Server health (based on application health,
not just server status)
• Number of open sessions
• Round Robin
• Hash
• Persistence: Subsequent packets in the same
session sent to the same server until the
session terminates.
High Availability with Cajun
The special configuration below shows how each
element is fully backed up to provide maximum
uptime:
• Server fails—The P333R-LB senses the loss
of the server and directs all new sessions to
the other servers that are available in the farm.
•
This process is transparent both to the user and
to the server, so no configuration is required (unlike
proxy servers, for example).
Unlike simple load-balancers, the Avaya load
balancing solution supports multiple persistence
methods. This enables the P333R-LB to fully
support eBusiness applications that require
continuous communication between the client
and server throughout a transaction session. The
following persistence methods are supported:
•
•
•
•
Avaya P330
Redundant
LAG
P880
Gigabit Ethernet
with LAG
Avaya P882
Avaya P580
Session address translation performed on
every packet
IP address hashing
Source address with inactivity timer
P333R-LB fails—enhanced VRRP ensures
transparent switchover to the second switch.
A special topology ensures the server
connection to the network.
Uplink fails—STA and port redundancy bring
the backup LAG on-line instantaneously.
Server Farm
Virtual IP A
IP IP IP IP
1 2 3 4
Avaya P333R-LB
Avaya P333R-LB
Gigabit Ethernet
with LAG
Communication without boundaries
*future
4