switches via NMI-T ( Network Management Interface for the Transport Network). The traffic from user connected to an ASON network contains data for both Transport and Control Plane. The user is connected to Transport plane via a PI (Physical Interface), while it communicates with the Control plane via a UNI ( User Network Interface). The Role of IETF While ITU has worked on the requirements and architecture of ASON based on the requirements on its members, it is explicitly aiming to avoid the development of new protocols, when existing ones will work fine. The IETF, on the other hand, has been tasked with the development of new protocols in response to general industry requirement. Therefore, while ITU already include the PNNI protocol for signaling in the Control plane, IETF has been developing GMPLS (Generalized MPLS) as a second option protocol to be used in the Control Plane for signalling. As a product of IETF, GMPLS uses IP to communicate between different components in the Control Plane. ITU-T documentation for ASON standardization The following is a list and description of architecture and requirements as published by ITU-T G.8080/Y.1304, Architecture for the automatically switched optical network (ASON) G.807/Y.1302, Requirements for automatic switched transport networks (ASTN) Call and Connection Management G.7713/Y.1704, Distributed call and connection management (DCM) G.7713.1/Y.1704.1, DCM signalling mechanism using PNNI/Q.2931 G.7713.2/Y.1704.2, DCM signalling mechanism using GMPLS RSVP-TE G.7713.3/Y.1704.3, DCM signalling mechanism using GMPLS CR-LDP Discovery and Link Management G.7714/Y.1705, Generalized automatic discovery techniques G.7715/Y.1706, Architecture and requirements of routing for automatic switched transport network G.7716/Y.1707, Architecture and requirements of link resource management for automatically switched transport networks G.7717/Y.1708, ASTN connection admission control. Other Related Recommendations G.872, Architecture of optical transport networks G.709/Y.1331, Interface for the optical transport network (OTN) G.959.1, Optical transport network physical layer interfaces G.874, Management aspects of the optical transport network element G.874.1, Optical transport network (OTN) protocolneutral management information model for the network element view. G.875, Optical transport network (OTN) management information model for the network element view G.7041/Y.1303, Generic framing procedure (GFP) G.7042/Y.1305, Link capacity adjustment scheme (LCAS) for virtual concatenated signals G.65x, series on optical fibre cables and test methods G.693, Optical interfaces for intra-office systems G.7710/Y.1701, Common equipment management function requirements G.7712/Y.1703, Architecture and specification of data communication network. G.806, Characteristics of transport equipment . Description methodology and generic functionality. See also Automatic switched-transport network (ASTN) References Fiber-optic communications Network protocols