HP StorageWorks MSA 2/8 HP StorageWorks QuickLoop Fabric Assist V3.1.x User Gu - Page 21

Using QuickLoop Sometimes, a single fabric loop device is attached to a port. In this case, the port would function as an FL_port. The attached device possesses either an N_port (if the device is fabric-capable) or an NL_port, in which case the device would be connected to the fabric in a loop configuration through an FL_Port on a switch. In this latter case a looplet is created. ■ E_port-Expansion port. A port is designated an E_Port when it is used as an interswitch expansion port to connect to the E_Port of another switch, to build a larger switch fabric, or to build a two-switch QuickLoop configuration. ■ looplet-A set of devices connected in a loop to a port that is itself a member of an arbitrated loop. By contrast, a single device rather than a loop might be connected to a port. Each device in a private loop must have a unique physical address. The devices in a QuickLoop are assigned a unique phantom AL_PA. ■ AL_PA-Arbitrated loop physical address. A one byte value used to identify a device in an arbitrated loop. During implementation and operation of StorageWorks SAN switches in a QuickLoop, messages are transmitted by devices as they come online. These messages, called LIPs, are in addition to normal data traffic. ■ LIP-Loop initialization primitive. Dual-switch QuickLoop In a dual-switch QuickLoop (QuickLoop Partners), the initialization process is driven by one of the switches, called the QuickLoop master. The role of the QuickLoop master is dynamically assigned at each instance of QuickLoop initialization, according to the following criteria: ■ If one switch receives LIPs from its looplets and the other does not, the switch that receives the LIPs is the QuickLoop master. ■ If both switches receive LIPs from their respective looplets, the switch with the lower domain ID is the QuickLoop master. QuickLoop Fabric Assist Version 3.1.x User Guide 21