Content for TS 25.423 Word version: 16.0.0

3.1 Definitions 3.2 Symbols 3.3 Abbreviations 4.1 Procedure Specification Principles 4.2 Forwards and Backwards Compatibility 4.3 Source Signalling Address Handling 4.4 Specification Notations 5.1 RNSAP Procedure Modules 5.2 Parallel Transactions
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1 Scope Word‑p. 25

The present document specifies the radio network layer signalling procedures of the control plane between RNCs in UTRAN, between RNC in UTRAN and BSS in GERAN Iu mode and between BSSs in GERAN Iu mode.

2 References

The following documents contain provisions which, through reference in this text, constitute provisions of the present document.

References are either specific (identified by date of publication, edition number, version number, etc.) or non specific.
For a specific reference, subsequent revisions do not apply.
For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document.

[1]

TS 23.003: "Numbering, addressing and identification".

[2]

TS 25.413: "UTRAN Iu Interface RANAP Signalling".

[3]

TS 25.426: "UTRAN Iur and Iub Interface Data Transport & Transport Layer Signalling for DCH Data Streams".

[4]

TS 25.427: "UTRAN Iur and Iub Interface User Plane Protocols for DCH Data Streams".

[5]

TS 25.435: "UTRAN Iub interface User Plane Protocols for Common Transport Channel Data Streams".

[6]

TS 25.104: "UTRA (BS) FDD; Radio transmission and Reception".

[7]

TS 25.105: "UTRA (BS) TDD; Radio Transmission and Reception".

[8]

TS 25.211: "Physical Channels and Mapping of Transport Channels onto Physical Channels (FDD)".

[9]

TS 25.212: "Multiplexing and Channel Coding (FDD)".

[10]

TS 25.214: "Physical Layer Procedures (FDD)".

[11]

TS 25.215: "Physical Layer - Measurements (FDD)".

[12]

TS 25.221: "Physical Channels and Mapping of Transport Channels onto Physical Channels (TDD)".

[13]

TS 25.223: "Spreading and Modulation (TDD)".

[14]

TS 25.225: "Physical Layer - Measurements (TDD)".

[15]

TS 25.304: "UE Procedures in Idle Mode".

[16]

TS 25.331: "RRC Protocol Specification".

[17]

TS 25.402: "Synchronisation in UTRAN, Stage 2".

[18]

ITU-T Recommendation X.680 (2002-07): "Information technology - Abstract Syntax Notation One (ASN.1): Specification of basic notation".

[19]

ITU-T Recommendation X.681 (2002-07): "Information technology - Abstract Syntax Notation One (ASN.1): Information object specification".

[20]

ITU-T Recommendation X.691 (2002-07): "Information technology - ASN.1 encoding rules - Specification of Packed Encoding Rules (PER)".

[21]

TS 25.213: "Spreading and modulation (FDD)".

[22]

TS 25.224: "Physical Layer Procedures (TDD)".

[23]

TS 25.133: "Requirements for support of Radio Resource management (FDD)".

[24]

TS 25.123: "Requirements for support of Radio Resource management (TDD)".

[25]

TS 23.032: "Universal Graphical Area Description (GAD)".

[26]

TS 25.302: "Services Provided by the Physical Layer".

[27]

TS 25.213: "Spreading and modulation (FDD)".

[28]

TR 25.921: (version.7.0.0) "Guidelines and Principles for Protocol Description and Error Handling".

[29] Void

[30]

ICD-GPS-200: "Navstar GPS Space Segment/Navigation User Interface".

[31]

RTCM-SC104: "RTCM Recommended Standards for Differential GNSS Service (v.2.2)".

[32]

TS 25.425: "UTRAN Iur and Iub Interface User Plane Protocols for Common Transport Channel data streams".

[33]

RFC 2460 (1998-12): "Internet Protocol, Version 6 (Ipv6) Specification".

[34]

RFC 768 (1980-08): "User Datagram Protocol".

[35]

TS 25.424: "UTRAN Iur Interface Data Transport & Transport Signalling for Common Transport Channel Data Streams".

[36] Void

[37] Void

[38]

TS 48.008: "Mobile-services Switching Centre - Base Station System (MSC - BSS) interface; Layer 3 specification".

[39]

TS 43.051: "GSM/EGDE Radio Access Network; Overall description - Stage 2".

[40]

TS 25.401: "UTRAN Overall Description".

[41]

TS 25.321: "MAC protocol specification".

[42]

TS 25.306: "UE Radio Access capabilities".

[43]

TS 25.101: "User Equipment (UE) radio transmission and reception (FDD) ".

[44]

RFC 2474 (1998-12): "Definition of the Differentiated Services Field (DS Field) in the Ipv4 and Ipv6 Headers".

[45]

RFC 2475 (1998-12): "An Architecture for Differentiated Services".

[46]

TS 25.222: "Multiplexing and Channel Coding (TDD) ".

[47]

TS 44.060: "General Packet Radio Service (GPRS); Mobile Station (MS) - Base Station System (BSS) interface; Radio Link Control/Medium Access Control (RLC/MAC) protocol".

[48]

TS 32.421: "Subscriber and equipment trace: Trace concepts and requirements".

[49]

TS 32.422: "Subscriber and equipment trace: Trace control and Configuration Management".

[50]

TS 25.346: "Introduction of the Multimedia Broadcast Multicast Service (MBMS) in the Radio Access Network (Stage-2)".

[51]

TS 23.246: "Multimedia Broadcast Multicast Service; Architecture and Functional Description".

[52]

TS 25.319: "Enhanced Uplink; Overall description; Stage 2".

[53]

Galileo OS Signal in Space ICD (OS SIS ICD), Issue 1.2. February 2014, European Union.

[54]

TS 23.251: "Network Sharing: Architecture and functional description".

[55]

IS-GPS-200, Revision D, Navstar GPS Space Segment/Navigation User Interfaces, March 7th, 2006.

[56]

IS-GPS-705, Navstar GPS Space Segment/User Segment L5 Interfaces, September 22, 2005.

[57]

IS-GPS-800, Navstar GPS Space Segment/User Segment L1C Interfaces, March 31, 2008.

[58]

Specification for the Wide Area Augmentation System (WAAS), US Department of Transportation, Federal Aviation Administration, DTFA01-96-C-00025, 2001.

[59]

IS-QZSS, Quasi Zenith Satellite System Navigation Service Interface Specifications for QZSS, Ver.1.0, June 17, 2008.

[60]

Global Navigation Satellite System GLONASS Interface Control Document, Version 5, 2002.

[61]

TS 36.401: "Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Architecture Description".

[62]

TS 36.104: "Base Station (BS) radio transmission and reception".

[63]

TS 25.308: "High Speed Downlink Packet Access (HSDPA); Overall description; Stage 2".

[64]

TS 36.133: "Requirements for support of radio resource management".

[65]

TS 23.195: "Provision of UE Specific Behaviour Information to Network Entities".

[66]

TS 24.008: "Mobile radio interface Layer 3 specification; Core network protocols; Stage 3".

[67]

TS 44.118: "Mobile radio interface layer 3 specification; Radio Resource Control (RRC) protocol".

[68]

TS 25.422: "UTRAN Iur interface signalling transport".

[69]

TS 45.005: "Technical Specification Group GSM/EDGE Radio Access Network; Radio transmission and reception".

[70]

BDS-SIS-ICD-2.0: "BeiDou Navigation Satellite System Signal In Space Interface Control Document Open Service Signal (Version 2.0)", December 2013.

[71]

TS 25.300: "Universal Terrestrial Radio Access Network (UTRAN); General description; Stage 2".

[72]

TS 36.101: "User Equipment (UE) radio transmission and reception".

3 Definitions, Symbols and Abbreviations Word‑p. 27

3.1 Definitions

For the purposes of the present document, the following terms and definitions apply:

Elementary Procedure:

RNSAP protocol consists of Elementary Procedures (Eps). An Elementary Procedure is a unit of interaction between two RNCs. An EP consists of an initiating message and possibly a response message. Two kinds of EPs are used:

Class 1: Elementary Procedures with response (success or failure);
Class 2: Elementary Procedures without response.

For Class 1 EPs, the types of responses can be as follows:

Successful

A signalling message explicitly indicates that the elementary procedure has been successfully completed with the receipt of the response.

Unsuccessful

A signalling message explicitly indicates that the EP failed.

Class 2 EPs are considered always successful.

Prepared Reconfiguration:

A Prepared Reconfiguration exists when the Synchronised Radio Link Reconfiguration Preparation procedure has been completed successfully. The Prepared Reconfiguration does not exist anymore only after either of the procedures Synchronised Radio Link Reconfiguration Commit or Synchronised Radio Link Reconfiguration Cancellation has been completed. In particular, the Prepared Reconfiguration still exists if the object (e.g. Radio Link) concerned by the Synchronised Radio Link Reconfiguration (e.g. in the case of an HS-DSCH Setup) is removed, but the UE Context still exists.

UE Context:

The UE Context contains the necessary information for the DRNC/DBSS to communicate with a specific UE. The UE Context is created by the Radio Link Setup procedure or by the Uplink Signalling Transfer procedure when the UE makes its first access in a cell controlled by the DRNS/DBSS or by Enhanced Relocation procedure when the procedure is the first dedicated RNSAP procedure for the UE. The UE Context is deleted by the Radio Link Deletion procedure, by the Common Transport Channel Resources Release procedure, or by the Downlink Signalling Transfer procedure when neither any Radio Links nor any common transport channels are established towards the concerned UE. The UE Context is identified by the SCCP Connection for messages using connection oriented mode of the signalling bearer and the D-RNTI for messages using connectionless mode of the signalling bearer, unless specified otherwise in the procedure text.

Distant RNC Context:

The Distant RNC context is created by the first Common Measurement Initiation Procedure or Information Exchange Initiation Procedure initiated by one RNC/BSS and requested from another RNC/BSS. The Distant RNC Context is deleted after the Common Measurement Termination, the Common Measurement Failure, the Information Exchange Termination or the Information Exchange Failure procedure when there is no more Common Measurement and no more Information to be provided by the requested RNC/BSS to the requesting RNC/BSS. The Distant RNC Context is identified by a connection oriented signalling bearer (See TS 25.422) as, for common measurements and information exchange, only the connection oriented mode of the signalling bearer is used.

Signalling radio bearer 2:

The signalling radio bearer 2 is used by the UE to access a GERAN cell in order to perform RRC procedures.

UE Link:

see definition in TS 25.346.

URA Link:

see definition in TS 25.346.

MBMS Bearer Service:

see defintion in TS 23.246.

MBMS session:

see defintion in TS 25.346.

MBMS session start:

see defintion in TS 25.346.

MBMS session stop:

see defintion in TS 25.346.

MBMS Selected Services:

see defintion in TS 25.346.

PUESBINE feature:

as defined in TS 23.195.

3.2 Symbols Word‑p. 28

Void.

3.3 Abbreviations Word‑p. 29

For the purposes of the present document, the following abbreviations apply:

A-GPS

Assisted-GPS

ALCAP

Access Link Control Application Part

APN

Access Point Name

ASN.1

Abstract Syntax Notation One

BDS

BeiDou Navigation Satellite System

BER

Bit Error Rate

BLER

Block Error Rate

BSS

Base Station Subsystem

CBSS

Controlling BSS

CCCH

Common Control Channel

CCPCH

Common Control Physical Channel

CCTrCH

Coded Composite Transport Channel

CFN

Connection Frame Number

C-ID

Cell Identifier

Compressed Mode

Core Network

CPICH

Common Pilot Channel

CRNC

Controlling RNC

CLTD

Closed Loop Transmit Diversity

DBDS

Differential BDS

DBSS

Drift BSS

C-RNTI

Cell Radio Network Temporary Identifier

Circuit Switched

CTFC

Calculated Transport Format Combination DCH Dedicated Channel

DGANSS

Differential GANSS

DGPS

Differential GPS

Downlink

DPC

Downlink Power Control

DPCCH

Dedicated Physical Control Channel

DPCH

Dedicated Physical Channel

DPDCH

Dedicated Physical Data Channel

DRNC

Drift RNC

DRNS

Drift RNS

D-RNTI

Drift Radio Network Temporary Identifier

DRX

Discontinuous Reception

DSCH

Downlink Shared Channel

Energy in single Code

E-AGCH

E-DCH Absolute Grant Channel

E-DCH

Enhanced UL DCH

E-HICH

E-DCH HARQ Acknowledgement Indicator Channel

E-PUCH

Enhanced Uplink Physical Channel (TDD only)

E-RNTI

E-DCH RNTI

E-RUCCH

E-DCH Random Access Uplink Control Channel (TDD only)

E-TFCI

E-DCH Transport Format Combination Indicator

E-UCCH

E-DCH Uplink Control Channel (TDD only)

E-UTRA

Evolved UTRA

EDSCHPC

Enhanced Downlink Shared Channel Power Control

EGNOS

European Geostationary Navigation Overlay Service

Elementary Procedure

FACH

Forward Access Channel

FDD

Frequency Division Duplex

F-DPCH

Fractional DPCH

Frame Number

Frame Protocol

F-TPICH

Fractional Transmitted Precoding Indicator Channel

GANSS

Galileo and Additional Navigation Satellite Systems

GERAN

GSM EDGE Radio Access Network

Geographical Area

GAGAN

GPS Aided Geo Augmented Navigation

GAI

Geographical Area Identifier

GLONASS

GLObal'naya Navigatsionnaya Sputnikovaya Sistema (Engl.: Global Navigation Satellite System)

GNSS

Global Navigation Satellite System

GPS

Global Positioning System

GRA

GERAN Registration Area

GSM

Global System Mobile

GWCN

Gateway Core Network

HSDPA

High Speed Downlink Packet Access

Hardware

Information Block

ICD

Interface Control Document

Identity or Identifier

Information Element

IMSI

International Mobile Subscriber Identity

Internet Protocol

IPDL

Idle Period DownLink

ISCP

Interference Signal Code Power

LAC

Location Area Code

LCR

Low Chip Rate (1.28 Mcps)

LCS

Location Services

MAC

Medium Access Control

MBMS

Multimedia Broadcast Multicast Service

MDT

Minimization of Drive Tests

MOCN

Multi-Operator Core Network

MRNC

MBMS Master RNC

Mobile Station

MSAS

Multi-functional Satellite Augmentation System

NACC

Network Assissted Cell Change

NAICS

Network Assisted Interference Cancellation and Suppression

NAS

Non Access Stratum

Reference Noise

NRT

Non Real Time

O&M

Operation and Maintenance

P(-)CCPCH

Primary CCPCH

PCH

Paging Channel

OTD

Observed Time Difference

P(-)CPICH

Primary CPICH

PCS

Personal Communication Services

PDSCH

Physical Downlink Shared Channel

PDU

Protocol Data Unit

PhCH

Physical Channel

PICH

Paging Indication Channel

PLCCH

Physical Layer Common Control Channel

Pos

Position or Positioning

PRACH

Physical Random Access Channel

PTP

Point To Point

PTM

Point To Multipoint

Packet Switched

PUESBINE

Provision of UE Specific Behaviour Information to Network Entities

Quality Estimate

QZSS

Quasi-Zenith Satellite System

RAC

Routing Area Code

RACH

Random Access Channel

RAN

Radio Access Network

RANAP

Radio Access Network Application Part

Radio Bearer

Radio Link

RLC

Radio Link Control

RLS

Radio Link Set

Rate Matching

RNC

Radio Network Controller

RNS

Radio Network Subsystem

RNSAP

Radio Network Subsystem Application Part

RNTI

Radio Network Temporary Identifier

RRC

Radio Resource Control

Real Time

RSCP

Received Signal Code Power

SBAS

Satellite Based Augmentation System

SBSS

Serving BSS

Receive or Reception

Sat

Satellite

SCCP

Signalling Connection Control Part

S(-)CCPCH

Secondary CCPCH

SCH

Synchronisation Channel

SCTD

Space Code Transmit Diversity

S-DPCCH

Secondary Dedicated Physical Control Channel

SDU

Service Data Unit

System Frame

SFN

System Frame Number

SHCCH

Shared Control Channel

SIR

Signal-to-Interference Ratio

SNA

Shared Network Area

SRB2

Signalling radio bearer 2

SRNC

Serving RNC

SRNS

Serving RNS

S-RNTI

Serving Radio Network Temporary Identifier

STTD

Space Time Transmit Diversity

TDD

Time Division Duplex

Transport Format

TFCI

Transport Format Combination Indicator

TFCS

Transport Format Combination Set

TFS

Transport Format Set

TGCFN

Transmission Gap Connection Frame Number

TMGI

Temporary Mobile Group Identity

ToAWE

Time of Arrival Window Endpoint

ToAWS

Time of Arrival Window Startpoint

TPC

Transmit Power Control

TrCH

Transport Channel

Time Slot

TSG

Technical Specification Group

TSTD

Time Switched Transmit Diversity

TTI

Transmission Time Interval

Transmit or Transmission

UARFCN

UTRA Absolute Radio Frequency Channel Number

UDP

User Datagram Protocol

UC-ID

UTRAN Cell Identifier

User Equipment

Uplink

UMTS

Universal Mobile Telecommunications System

URA

UTRAN Registration Area

U-RNTI

UTRAN Radio Network Temporary Identifier

USCH

Uplink Shared Channel

UTC

Universal Coordinated Time

UTRA

Universal Terrestrial Radio Access

UTRAN

Universal Terrestrial Radio Access Network

WAAS

Wide Area Augmentation System

4 General Word‑p. 32

4.1 Procedure Specification Principles

The principle for specifying the procedure logic is to specify the functional behaviour of the DRNC/CRNC exactly and completely. The SRNC functional behaviour is left unspecified. The Physical Channel Reconfiguration procedure, [TDD - the UE Measurement Inititation, the UE Measurement Reporting, UE Measurement Termination, UE Measurement Failure,] and the Reset procedure are an exception from this principle.

The following specification principles have been applied for the procedure text in subclause 8:

The procedure text discriminates between:
1. Functionality which "shall" be executed
  The procedure text indicates that the receiving node "shall" perform a certain function Y under a certain condition. If the receiving node supports procedure X but cannot perform functionality Y requested in the REQUEST message of a Class 1 EP, the receiving node shall respond with the message used to report unsuccessful outcome for this procedure, containing an appropriate cause value.
2. Functionality which "shall, if supported" be executed
  The procedure text indicates that the receiving node "shall, if supported," perform a certain function Y under a certain condition. If the receiving node supports procedure X, but does not support functionality Y, the receiving node shall proceed with the execution of the EP, possibly informing the requesting node about the not supported functionality.

Any required inclusion of an optional IE in a response message is explicitly indicated in the procedure text. If the procedure text does not explicitly indicate that an optional IE shall be included in a response message, the optional IE shall not be included. For requirements for including Criticality Diagnostics IE, see section 10. For examples on how to use the Criticality Diagnostics IE, see Annex C.

4.2 Forwards and Backwards Compatibility

The forwards and backwards compatibility of the protocol is assured by a mechanism in which all current and future messages, and IEs or groups of related IEs, include ID and criticality fields that are coded in a standard format that will not be changed in the future. These parts can always be decoded regardless of the standard version.

4.3 Source Signalling Address Handling

The sender of an RNSAP messages shall include the Source Signalling Address, i.e. the Signalling Address of the sending node.

4.4 Specification Notations

For the purposes of the present document, the following notations apply:

[FDD]

This tagging of a word indicates that the word preceding the tag "[FDD]" applies only to FDD. This tagging of a heading indicates that the heading preceding the tag "[FDD]" and the section following the heading applies only to FDD.

[TDD]

This tagging of a word indicates that the word preceding the tag "[TDD]" applies only to TDD, including 3.84Mcps TDD, 7.68Mcps TDD and 1.28Mcps TDD. This tagging of a heading indicates that the heading preceding the tag "[TDD]" and the section following the heading applies only to TDD, including 3.84Mcps TDD, 7.68Mcps TDD and 1.28Mcps TDD.

[3.84Mcps TDD]

This tagging of a word indicates that the word preceding the tag "[3.84Mcps TDD]" applies only to 3.84Mcps TDD. This tagging of a heading indicates that the heading preceding the tag "[3.84Mcps TDD]" and the section following the heading applies only to 3.84Mcps TDD.

[1.28Mcps TDD]

This tagging of a word indicates that the word preceding the tag "[1.28Mcps TDD]" applies only to 1.28Mcps TDD. This tagging of a heading indicates that the heading preceding the tag "[1.28Mcps TDD]" and the section following the heading applies only to 1.28Mcps TDD.

[7.68Mcps TDD]

This tagging of a word indicates that the word preceding the tag "[7.68Mcps TDD]" applies only to 7.68Mcps TDD. This tagging of a heading indicates that the heading preceding the tag "[7.68Mcps TDD]" and the section following the heading applies only to 7.68Mcps TDD.

[FDD - …]

This tagging indicates that the enclosed text following the "[FDD - " applies only to FDD. Multiple sequential paragraphs applying only to FDD are enclosed separately to enable insertion of TDD specific (or common) paragraphs between the FDD specific paragraphs.

[TDD - …]

This tagging indicates that the enclosed text following the "[TDD - " applies only to TDD including 3.84Mcps TDD, 7.68Mcps TDD and 1.28Mcps TDD. Multiple sequential paragraphs applying only to TDD are enclosed separately to enable insertion of FDD specific (or common) paragraphs between the TDD specific paragraphs.

[3.84Mcps TDD - …]

This tagging indicates that the enclosed text following the "[3.84Mcps TDD - " applies only to 3.84Mcps TDD. Multiple sequential paragraphs applying only to 3.84Mcps TDD are enclosed separately to enable insertion of FDD and TDD specific (or common) paragraphs between the 3.84Mcps TDD specific paragraphs.

[1.28Mcps TDD - …]

This tagging indicates that the enclosed text following the "[1.28Mcps TDD - " applies only to 1.28Mcps TDD. Multiple sequential paragraphs applying only to 1.28Mcps TDD are enclosed separately to enable insertion of FDD and TDD specific (or common) paragraphs between the 1.28Mcps TDD specific paragraphs.

[7.68Mcps TDD - …]

This tagging indicates that the enclosed text following the "[7.68Mcps TDD - " applies only to 7.68Mcps TDD. Multiple sequential paragraphs applying only to 7.68Mcps TDD are enclosed separately to enable insertion of FDD and TDD specific (or common) paragraphs between the 7.68Mcps TDD specific paragraphs.

Procedure

When referring to an elementary procedure in the specification, the Procedure Name is written with the first letters in each word in upper case characters followed by the word "procedure", e.g. Radio Link Setup procedure.

Message

When referring to a message in the specification, the MESSAGE NAME is written with all letters in upper case characters followed by the word "message", e.g. RADIO LINK SETUP REQUEST message.

When referring to an information element (IE) in the specification, the Information Element Name is written with the first letters in each word in upper case characters and all letters in Italic font followed by the abbreviation "IE", e.g. Transport Format Set IE.

Value of an IE

When referring to the value of an information element (IE) in the specification, the "Value" is written as it is specified in subclause 9.2 enclosed by quotation marks, e.g. "Abstract Syntax Error (Reject)".

5 RNSAP Services Word‑p. 33

5.1 RNSAP Procedure Modules

The Iur interface RNSAP procedures are divided into five modules as follows:

RNSAP Basic Mobility Procedures;
RNSAP Dedicated Procedures;
RNSAP Common Transport Channel Procedures;
RNSAP Global Procedures;
RNSAP MBMS Procedures.

The Basic Mobility Procedures module contains procedures used to handle the mobility within UTRAN, within GERAN and between UTRAN and GERAN.

The Dedicated Procedures module contains procedures that are used to handle DCHs, [FDD - F-DPCH,] [TDD - DSCHs, USCHs], HS-DSCH and E-DCH between two RNSs. If procedures from this module are not used in a specific Iur, then the usage of DCH, [FDD - F-DPCH,] [TDD - DSCH, USCH,] HS-DSCH and E-DCH traffic between corresponding RNSs is not possible.

The Common Transport Channel Procedures module contains procedures that are used to control common transport channel data streams (excluding the DSCH, HS-DSCH and USCH) over Iur interface.

The Global Procedures module contains procedures that are not related to a specific UE. The procedures in this module are in contrast to the above modules involving two peer CRNCs/CBSSs.

The MBMS Procedures module contains procedures that are specific to MBMS and used for cases that cannot be handled by other modules.

5.2 Parallel Transactions Word‑p. 34

Unless explicitly indicated in the procedure specification, at any instance in time one protocol peer shall have a maximum of one ongoing RNSAP Dedicated procedure related to a certain UE.

6 Services Expected from Signalling Transport

The signalling transport shall provide two different service modes for the RNSAP.

Connection oriented data transfer service. This service is supported by a signalling connection between two RNCs. It shall be possible to dynamically establish and release signalling connections based on the need. Each active UE shall have its own signalling connection. The signalling connection shall provide in sequence delivery of RNSAP messages. RNSAP shall be notified if the signalling connection breaks.
Connectionless data transfer service. RNSAP shall be notified in case a RNSAP message did not reach the intended peer RNSAP entity.