IBM 201 - Manual (Page 58)

Fast Etherchannel (FEC) is a proprietary technology developed by Cisco. With FEC,
you can create a team of two to four ports on the Quad-port 10/100 Ethernet PCI
Adapter in to increase transmission and reception throughput. This feature may also
be referred to as load balancing, port aggregation, or trunking. When you configure
this feature, the adapter ports comprising the FEC team or group create a single
high-speed, fault-tolerant link between the engine and the Ethernet switch sharing
one IP address. With FEC, fault tolerance and load balancing is provided for both
outbound and inbound traffic, unlike other load balancing schemes that only
balance outbound traffic.
FEC requires an Ethernet switch with FEC capability. The FEC implementation on
the Quad-port 10/100 Ethernet Adapter does not support the optional Port
Aggregation Protocol (PAgP) feature of FEC-capable Ethernet switches.
46 NAS 200 User’s Reference