Computer Accessories User Manual

12 X Reviewing REO 9000 Concepts and Requirements
Overland Storage REO 9000 with ProtectionPAC Software
Fibre Channel (FC)
Instead of, or in addition to, using iSCSI and the TCP/IP protocol to
transmit information over a network, you also have the option of using a
SAN that makes use of the FC and Small Computer System Interface
(SCSI) protocols. The FC protocol uses two additional protocols to
communicate at the hardware level: Fibre Channel Arbitrated Loop (FC-
AL), which communicates with hubs, and Fibre Channel Switched (FC-
SW), which communicates with switches. The SCSI protocol provides the
communication link at the higher level, between the hardware and the
software.
You can use all three basic FC SAN topologies with the REO Appliance:
 Point-to-point. This topology provides a direct connection between
two N_Ports.
 Arbitrated loop. In an arbitrated loop, NL_Ports and FL_Ports are
daisy-chained with hubs, which means that only one device can send
data at a time.
 Switched fabric. Switched fabric consists of one or more switches
that are interconnected, and multiple nodes connected to the switches.
The REO Appliance supports the following types of ports for FC:
FC uses strict naming conventions to support unique, 64-bit names for
the worldwide node name (WWNN) and the worldwide port name
(WWPN). These names are pre-assigned by the manufacturers of the
different hardware components used in an FC.
Port Type Represents Associated Topology
N_Port Node Port Connects point-to-point or to F_Port
NL_Port Node Loop Port N_Ports that can connect to an arbitrated loop