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25 series - Iur interface protocol stack

Up to the 25 series 25.420 - UTRAN Iur interface general aspects and principles 25.427 - UTRAN Iur/Iub interface user plane protocol for DCH data streams 25.425 - UTRAN Iur interface user plane protocols for Common Transport Channel data streams 25.426 - UTRAN Iur and Iub interface data transport & transport signalling for DCH data streams 25.424 - UTRAN Iur interface data transport & transport signalling for Common Transport Channel data streams 25.426 - UTRAN Iur and Iub interface data transport & transport signalling for DCH data streams 25.424 - UTRAN Iur interface data transport & transport signalling for Common Transport Channel data streams 25.421 - UTRAN Iur interface layer 1 25.422 - UTRAN Iur interface signalling transport 25.423 - UTRAN Iur interface Radio Network Subsystem Application Part (RNSAP) signalling

Description

The Iur interface connects different RNCs together. It is new to UMTS, and is typically (but not exclusively) used to support mobiles that are in soft handover to Node B's controlled by different RNCs.

Like the other UTRAN interfaces, its protocol stack is divided into two layers. All the UMTS-related issues are in the radio network layer, while the transport network layer contains standard technology used for the underlying transport. The stack is also divided into three planes. The user plane handles data streams that eventually reach the UE, the control plane handles Iur signalling messages and the transport network control plane manages the underlying transport.

So there are two important protocols here: the RNSAP defines the signalling messages exchanged over the Iur interface and the frame protocols define the data streams.

Abbreviations

RNCRadio network controller
RNSAPRadio network subsystem application part
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