Avaya P333R-LB Installation And Configuration Manual page 169

Chapter 14 Load Balancing in the P333R-LB
with the Virtual Server IP before forwarding them to the clients.
Note: In complex routing topologies where alternative paths between the Real
Servers and clients might exist, the returning packets could reach the client via a
path external to the P333R-LB. These packets would be labelled with the real IP of
the Real Server, and not the VIP that the client recognizes, causing the session to fail.
In a situation where this is possible, use Full NAT to prevent this from occurring.
For more information, refer to Full NAT Load Balancing on page 30.
Avaya P333R-LB User's Guide 27