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)@ distributed control plane communications (e.g.@ signalling and routing) related to multiprotocol label switching ?C transport profile (MPLS-TP)@ 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 ?C other protocols (other than IP or OSI) are outside the current scope of this Recommendation. The DCN provides Layer 1 (physical)@ Layer 2 (data-link) and Layer 3 (network) functionality and consists of routing/switching functionality interconnected via links. These links can be implemented over various interfaces@ including wide area network (WAN) interfaces@ local area network (LAN) interfaces@ and embedded communication channels (ECCs). Various applications (e.g.@ TMN@ ASON@ etc.) require a packet-based communication network to transport information between various components. For example@ the TMN requires a communication network@ which is referred to as the management communication network (MCN) to transport management messages between TMN components (e.g.@ network element function (NEF) component and operations support function (OSF) component). ASON and MPLS-TP require communication networks@ which are referred to as signalling communication networks (SCNs) to transport signalling and routing messages between functional control plane components (e.g.@ connection controller (CC) components and routing controller (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 this Recommendation support connectionless network services. Additional functions may be added in future versions of this Recommendation to support connection-oriented network services. This 2010 revision of this Recommendation provides the requirements for the MPLS transport profile (MPLS-TP) signalling communication channel (SCC) and management communication channel (MCC) data communication functions. The part of this Recommendation that addresses MPLS for transport networks complies with the transport profile of MPLS architecture as defined by IETF. In the event of a difference between this ITU-T Recommendation and any of the normatively referenced RFCs for MPLS-TP@ the RFCs will take precedence.