FW 05.01.00 and SW 07.01.00 HP StorageWorks SAN High Availability Planning Guide (AA-RS2DC-TE, June 2003)

Planning Considerations for Fibre Channel Topologies
65SAN High Availability Planning Guide
Public Versus Private Loops
Arbitrated loop switches support operation of public and private loops as follows:
■ Public loop — A public loop is connected to a switched fabric (through the
switch B_Port) and the switch has an active embedded FL_Port that is user
transparent. All devices attached to the loop can communicate with each
other, and public devices attached to the loop can communicate with
fabric-attached devices. FL_Port operation is not affected by the switch
operating mode (shared or switched). Public loop connectivity is illustrated in
Figure 25.
Figure 25: Public loop connectivity
■ Private loop — A private loop is not connected to a switched fabric and the
switch’s embedded E_Port and FL_Port are inactive. All devices attached to
the loop can only communicate with each other. Private loop connectivity is
illustrated in Figure 26 on page 66.