plane are: NBAP (Node-B Application Part) is the signaling protocol responsible for the control of the Node B by the RNC. The NBAP protocol is carried out over the lub interface. 3 UMTS Terrestrial Radio Access Network (UTRAN) The NBAP protocol is subdivided into Common and Dedicated NBAP (C-NBAP and D-NBAP), where C-NBAP controls the overall Node B functionality and D-NBAP controls separate cells or sectors of the Node B. ALCAP (Access Link Control Application Part) is the control plane protocol for the transport layer. It is used to set up the transport bearers (data bearer) for the user plane. It is also carried over the lub interface. RNSAP (Radio Network Subsystem Application Part) is in charge of communications between RNCs and is carried on the Iur interface. Unlike NBAP, RNSAP is a symmetric protocol, thus run by two RNCs, of which one takes the role of SRNC and the other acts as DRNC. RANAP (Radio Access Network Application Part) handles communication between RNC and the core network and is carried over the Iu interface. It is used to set up and maintain Control Plane and User Plane connections across the Iu interface thus handling communication between UTRAN and CN. Whereas the Control Plane performs all control functionality, the actual user traffic, such as coded voice or IP packets, is conveyed through the User Plane. The User Plane consists of the Data Streams and Data Bearers. Data Streams contain the user data that are transparently transmitted in the UTRAN. The Data Steams are formed on the Radio Network Layer characterized by one or more frame protocols specified for that interface. The Data Bearers are used to transport user data (Data Streams) across the interface on the Transport Network Layer. The Transport Network User Plane includes the Data Bearers in the User Plane and the Signaling Bearers for the Application Protocol in the Control Plane. The Transport Network Control Plane, which is located between the Control Plane and the User Plane, is used for all control signaling within the Tran