Storage Network
Fibre Channel foundations
FC addressing uses the domain ID, the FCID, and the pWWN/nWWN. Know the port types: F (fabric), FL (fabric loop), E (ISL), TE (trunking E), NP (NPV proxy), TF (trunking F), and SD (span destination). A VSAN is an independent fabric instance; switches linked with an ISL must use TE ports carrying the required VSANs. FLOGI registers the host with the fabric, FDISC supports additional logins (NPIV), and the name server lists logged-in devices.
Zoning
Standard practice is single-initiator, single-target (or single-initiator, multiple-target) zones built from pWWNs, aliases, or device aliases, grouped into a zone set that must be activated per VSAN. A zone that is configured but not activated is not enforced.
NPV and NPIV
An NPV switch is a host-like edge device whose uplinks are NP ports to the core; NPIV lets it log in many end devices with distinct FCIDs.
FCoE
FCoE needs lossless Ethernet: PFC on the FCoE class, consistent VLAN-to-VSAN mapping on both ends, and FIP snooping on the bridge.
Traps
Mismatched VSAN IDs on the two ends of an ISL; unactivated zone sets; assuming soft zoning (name server only) equals hard zoning (enforced in hardware); running FCoE over a link without PFC.
Rule of thumb
Host cannot see its LUN? Check in order: FLOGI/name server entry, zoning (same active zone set, both WWNs), then array LUN masking. That order isolates fabric versus array problems quickly.