DANSK DS/ISO/IEC 14165-122 PDF

This part of ISO/IEC 14165 specifies signaling interface enchancements for FC-PH, to allow L_Ports to operate with an arbitrated loop topology. This standard defines L_Ports that retain the functionally of Ports as specified in FC-PH. The Arbitrated Loop topology attaches multiple communicating points in a loop wothout requiring switches.
The Arbitrated Loop topology is a distributed topology where each L_Port includes the minimum necessary function to establish a Loop circuit. A single FL_Port connected to an Arbitrated Loop allows multiple NL_Ports to attach to a Fabric.
When an L_Port is operating on a Loop with at least one other L_Port, the L_Port uses the protocol extensions to FC-PH that are specified in this standard.
When an L_Port is connected with an N_Port, the L_Port communicates using the protocol defined in FC-PH.
Each L_Port may use a self-discovering procedure to find the correct operating mode without the need for external controls.