Your customer is a regional bank with branches in two different cities. Each branch is run as an isolated independent business and IT manages their…

FC-FC (Fibre Channel-to-Fibre Channel) routing is the specific technology designed to enable communication between devices in separate, autonomous SAN fabrics without merging them. Each fabric maintains its own independent fabric services (e.g., name server, zoning database), which limits the scope of any potential failure to the local fabric. A routing service, typically on a backbone switch or dedicated router, facilitates the selective and secure data flow (replication) between the two sites. This directly meets the customer's requirement for disaster recovery connectivity while keeping the fabrics isolated.

A. FCIP: FCIP is a transport protocol for tunneling Fibre Channel frames over an IP network. While used for long-distance SAN extension, it does not, by itself, prevent fabrics from merging.
C. NPIV: N-Port ID Virtualization allows a single physical Fibre Channel port to register multiple WWNs, primarily for server virtualization. It operates within a single fabric and does not connect separate fabrics.
D. Fabric partitioning: This term typically refers to Virtual Fabrics (VSANs/Logical Switches), which partition a single physical switch into multiple isolated fabrics. It does not provide a solution for connecting two geographically separate fabrics.

1. HPE B-series SAN Design Reference Guide (Page 219, "Fibre Channel routing"): "Fibre Channel routing provides a way to transparently connect devices in different fabrics without merging the fabrics. Each fabric is a separate administrative domain with its own set of fabric services. This allows for fabric scalability and fault isolation." This document explicitly states that FC routing connects fabrics without merging them, matching the question's requirements.

2. Brocade Fabric OS Administrator's Guide, 9.0.x (Page 613, "Integrated Routing overview"): "Integrated Routing provides Fibre Channel routing-based connectivity between fabrics without requiring the fabrics to merge. Each fabric is a separate administrative domain with its own set of fabric services. This allows for fabric scalability and fault isolation." (Note: HPE B-Series switches run Brocade Fabric OS).

3. Brocade Extension Configuration Guide, 9.0.x (Page 21, "FCIP and routing"): "FCIP is a transport protocol that runs over a standard TCP/IP network. FCIP is transparent to the fabric services... You can use FCIP to connect islands of SANs into a single fabric or to provide a connection between fabrics in an FC-FC routing environment." This clarifies that FCIP is the transport, while FC-FC routing is the logical service that keeps fabrics separate.