Fibre Channel Addressing and Routing Fibre Channel Addressing
Fabric Address Space
Switch assigns a FC address to each port at fabric login:
Like a telephone number or residence address May differ from one login to the next Three 8-bit fields:
Domain
Bit 23 16 15
One address space per fabric
Area
08 07
Port
00
Every Fibre Channel Port and Node have a World Wide Name (WWN), a unique identifier which is embedded into the port or node during the manufacturing process: • Vendors buy blocks of WWNs from Naming Authorities such as IEEE and allocate them to devices in the manufacturing process.
• Fibre Channel Addresses (FC_IDs) are dynamically assigned by a switch (for switch fabric), during Loop Initialization in FC_AL and by the port with the lowest WWN in Point to Point.
• WWNs follow a port and can be compared with a person’s name (Mr. Smith is always Mr. Smith no matter where he lives or works).
• FC-IDs can be different as a device is moved from Port to Port on a switch. This can be compared to a telephone number or a house address. The WWN (Mr. Smith) is always the same but the FC_ID can vary (Mr. Smith’s house address or telephone number). Mr. Smith can move house or change his telephone number – but he is still Mr. Smith.