User's Guide

Appendix D Fibre Channel Topology
298 Quantum DX-Series Software Interface Guide
• Point-to-Point (Fibre Channel device is connected directly to the Fibre
Channel host)
• Arbitrated Loop (multiple Fibre Channel devices are connected to a
switch or hub in a Fibre Channel network or fabric)
Figure 3 Fibre
Channel Topologies
Fibre Channel
device
Fibre Channel
host
Point-to-Point
Fiber Channel
switch or hub
Fibre
device
Channel
Fibre
device
Channel
Fibre
device
Channel
Fibre
device
Channel
Fibre
device
Channel
Fibre
device
Channel
Arbitrated Loop or Fabric
Fibre Channel
Addressing
4
Unlike many LAN technologies that use a fixed six-byte Media Access
Control (MAC) address, Fibre Channel uses a three byte address
identifier, which is dynamically assigned during Login. N_Ports transmit
frames from their own Source_ID (S_ID) to a Destination_ID (D_ID).
Addresses in the range of hex'FFFFF0' to hex'FFFFFE' are special, well-
known addresses uses for such things as the Fabric, Alias Server, or the
Multicast Server. Before Fabric Login, the N_Port's S_ID is undefined:
hex'000000'. Hex'FFFFFF' is reserved for broadcast. In a point-to-point
topology, Fabric Login will fail of course, and the two ports will simply
chose two unique addresses.