What is Hop in SAN fabric?
When Fibre Channel traffic is going from one E_Port over an ISL to another E_Port, is one hop.
ISLs are made from connecting an E_Port to an E_Port.
There is a hop count limit in Fabric. This limit is set by the fabric operating system and is used to derive a frame hold time value for each switch. This value is the maximum amount of time that a frame can be held in a switch before it is dropped, or the fabric indicates that it is too busy. The hop count limits must be investigated and considered in any SAN design work because it has a major effect on the proposal.
Fabric shortest path first(FSPF) is based on the hop count.