Fibre Channel Addressing and Routing Fibre Channel Addressing
Address Assignment
• Each switch and every port has a unique worldwide name (WWN)
• Each switch element is assigned a contiguous address pool (Domain):
– Address pool size is variable depending on the fabric configuration and the vendor
– All operating F_Ports assigned addresses from the pool
– E_Ports connected to other E_Ports are also assigned addresses from the same pool
• N_Ports inherit the addresses of the F_Ports that they are connected to during fabric login
Addressing and scalability: • 24 bit addressing provides 16,777,216 addresses, however some addresses are reserved and assigned as well known addresses so the address pool is reduced to 15,663,104 addresses.
• There can be a maximum of 239 switches in a fabric and the largest switch or director available today has only 256 ports so today’s practical limit is further reduced to 61184 ports. (239 x 256). However, with 16 port switches the total port count is reduced to 3824.
• Fabrics also consume port addresses for the switch interconnections. This further reduces the number of ports available for device connection to the fabric. The exact number will depend upon the configuration.