This part of ISO/IEC 14165 defines mappings for transporting Fibre Channel frames across ATM, SONET and TCP/IP backbone networks. This part of ISO/IEC 14165 consists of three distinct Fibre Channel mappings resulting in the following three specifications: — FC-BB-2_ATM (FC over ATM backbone network) — FC-BB-2_SONET (FC over SONET backbone network) — FC-BB-2_IP (FC over TPC/IP backbone network) The backbone mappings support the attachment of fibre channel switches using the facilities of the underlying backbone network. Mappings of fibre channel to ATM and SONET are completely specified in this FC-BB-2 standard. With respect to TCP/IP, the FC-BB-2 and IETF Fibre Channel over TCP/IP specifications together describe how Fibre Channel frames are transported over a TCP/IP backbone. The FC-BB-2 standard describes the Fibre Channel characteristics associated with the encapsulation and transportation of Fibre Channel frames using Fibre Channel over TCP/IP. The IETF specifications provide details regarding the encapsulation and transportation of Fibre Channel frames over a TCP/IP backbone.