Communicator e3000 MPE/iX Release 7.5 (Software Release C.75.00) (30216-90336)

Chapter 4
Fibre Channel Device and Adapter Support on HP e 3000 Systems
Fibre Channel Device Adapter Support
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more ports to provide a physical interface for communicating with other nodes via their ports. The port is a
hardware attachment that allows the node to send and receive information via the physical interface. Ports
may be integrated into the device or packaged as a separate pluggable card. Many peripheral devices such as
disk or tape drives use integrated ports while most host systems use pluggable Host Bus Adapter (HBA) ports
for flexibility. Fibre channel protocol allows transporting of upper layer protocols like SCSI command set over
it, thus enabling it to be used for connecting mass storage devices.
Each fibre channel node contains at least one hardware interface port that connects the node to the topology
and transports information to or from other ports. This port is referred to as a node port or N_Port for short. A
node may have a single N_Port or multiple N_Ports.
Each N_Port has a Port_Name, which is a unique 64-bit identifier assigned to the port at the time of
manufacture or installation. Since no two ports in the world are assigned the same name, it results in a
unique “World-Wide Name” (WWN). Each N_Port also has one or more 24-bit address identifiers called the
N_Port ID, which is used to address the node within a topology and route information to it.
Ports are connected together through an interface topology. The topology consists of the physical interface and
interconnection scheme. The physical interface determines the signaling rate and communication distances.
It defines transmission mechanisms such as optical of electrical signaling and specifies the cables and
connectors used by that interface. The topology defines the interconnection scheme. It determines how many
nodes can be connected together, how information is routed among the nodes, total bandwidth available and
delivery latencies.
Fibre Channel Topologies
Fibre Channel allows three different types of topologies for interconnecting nodes. They are:
1. switched fabric
2. arbitrated loop
3. point-to-point
A Fabric topology is a mesh of host systems, FC devices and FC switches interconnected with fibre channel
cables. At least one FC switch is required to form a fabric topology. Communication between any two nodes in
the fabric happens through the switch directly without the intervention of other nodes. In a fabric, each node
is uniquely identified using the 24-bit N_Port ID. The N_Port ID is assigned for each FC host or device in the
fabric by the fabric controller present inside the FC switch.
Figure 4-3 Fibre Channel Fabric
Host
FC Switch
Host
Device Device
Device