The IPFE acts as a specialized layer-3 router. The various servers to which the IPFE routes are divided into up to 16 groups, called Target Sets. Each of the target sets are assigned a shared Target Set Address. The IPFE Architecture assumes that either two connections are maintained at all times, in active/active or active/standby, or that a single connection is maintained, with a backup address to which it can establish a connection if the first connection fails.
When the IPFE routes packets to application servers, it does not perform any rewriting of the packet. This means that neither the source IP address nor the destination IP address changes as it passes through the IPFE. The IPFE behaves as an IP router and does not act as a network address translator (NAT).
