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Networking Fundamentals
Fibre Channel
a high-speed access
method that typically
uses fi ber-optic cable
as network media.
Network Address
Authority (NAA)
a naming standard
that consists of
the “naa.” prefi x
followed by a string
of hexadecimal
characters. It was
developed by
the International
Committee for
Information
Technology
Standards (ICITS).
Fibre Channel
Fibre Channel is a high-speed access method that typically uses fi ber-optic
cable as network media. It may also use copper core cable and wireless. The
term Fibre Channel also refers to a set of standards and a protocol. The Fibre
Channel standard provides a relatively high-data transmission rate between
supercomputers, mainframes, servers, and desktops. Fibre Channel is often used
for storage area network (SAN) access. There are three common Fibre Channel
topologies: point-to-point, arbitrated loop, and fabric, Figure 9-26.
A fi ber channel device uses a Network Address Authority (NAA), which is
a naming standard developed by the International Committee for Information
Technology Standards (ICITS). The NAA address consists of the “naa.” prefi x
followed by a string of hexadecimal characters. For example, naa.02034D12B12124.
Fibre Channel Point-to-Point Topology
A Fibre Channel point-to-point topology is simply a straight connection or
channel between two points, such as a mainframe and a server. The channel is
isolated from other channels or media, and total bandwidth is dedicated to the
channel between the two devices.
Fibre Channel Arbitrated Loop Topology
The Fibre Channel arbitrated loop is a common Fibre Channel topology.
It looks similar to the Token Ring topology. The arbitrated loop differs from
Token Ring in that two devices in the loop set up a direct communication link,
or channel, for the duration of the data transfer. In Token Ring network, a token
is passed around the ring while one device on the ring controls communication.
Token Ring has a maximum control time of approximately 8 milliseconds
in contrast to the arbitrated loop standard, which allows two devices to
communicate until all the data requested has been transferred.
The arbitrated loop is limited to 127 connections. It is used to move large
volumes of data between two devices such as a disk storage array and a server.
It is not used for sporadic communication between multiple nodes as it is on a
Token Ring network.
Figure 9-26.
Three major topologies associated with Fibre Channel systems are point-to-point, arbitrated loop, and fabric switched.
Station1 Station2
Point-to-point
Channel
Station1 Station2
Station3 Station4
Arbitrated loop
Station1
Station1
Station2
Station2
Fabric switched