This Recommendation defines the architecture requirements for a Data Communication Network (DCN) which may support distributed management communications related to the Telecommunication Management Network (TMN), distributed control plane communications (e.g., signalling and routing) related to the Automatically Switched Optical Network (ASON), and other distributed communications (e.g., Orderwire or Voice Communications, Software Download). The DCN architecture considers networks that are IP-only, OSI-only, and mixed (i.e., support both IP and OSI). The interworking between parts of the DCN supporting IP-only, parts supporting OSI-only, and parts supporting both IP and OSI are also specified. Various applications (e.g., TMN, ASON, etc.) require a packet-based communications network to transport information between various components. For example, the TMN requires a communications network, which is referred to as the Management Communication Network (MCN) to transport management messages between TMN components (e.g., NEF component and OSF component). ASON requires a communication network which is referred to as the Signalling Communication Network (SCN) to transport signalling and routing messages between ASON components (e.g., CC components and RC components). This Recommendation specifies data communication functions that can be used to support one or more application's communication network. The data communication functions provided in the 11/2001 version of this Recommendation support connection-less network services. The 3/2003 revision of the Recommendation adds the support of connection-oriented network SCN services by including specific MPLS-based mechanism. This 2008 revision of the Recommendation adds the requirements of the OTN ECC data-link layer termination function and the Transport MPLS (T-MPLS) SCC data link layer termination function. This Recommendation forms part of a family of Recommendations covering transport networks.

The "LC text with revmarks" file, showing explicit changes relative to the 03/2003 version of G.7712/Y.1703, has been posted as an aid to interested parties in the AAP review of proposed G.7712/Y.1703 (2008). Should any discrepancies be detected between this file and the official Last Call file that was posted on 29 February 2008, the official file shall be understood as authoritative.