IUB OVER ATM AND IP

WCDMA RAN Interface Protocols

NBAP-CNBAP-DQ2630

User-PlaneMub NBAP-C

NBAP-DQ2630

User-PlaneMub

RNSAPQ2630

User-Plane

RANAPQ2630

User-Plane

RANAPUser-Plane

RNC RNCRBS

MSN

MSCSGSN

MubMur

Router

O&M OSS-RC

Iub

Iur

Iu-CS Iu-PS

IUB LINK

•The Iub interface is defined as the logical interface between an RNC and a Node B on UTRAN network topology.

• The Iub interface allows the RNC and the Node B to negotiate about radio resources, for example to add and delete cells controlled by the Node B to support communication of the dedicated connection between UE and SRNC.

Protocol Structure for the Iub interface

1) The Physical Layer consists of the basic hardware transmission technologies of a network. It is about the necessary hardware to realize physical communication between RNC and Node B.

2) The Transport Network Layer provides end-to-end communication services for applications; it will have the necessary protocols to send signaling and services to Radio Layer.

3) The Radio Network Layer All UTRAN related issues are visible only in this layer and it will manage the Application protocol for control plane and Data streams for user plane.

The protocol stack is also divided in:

• Control Plane: is an application protocol which define the mechanisms used for establishing, releasing and managing bearers as well as control procedures; it is involved in signaling process

• User Plane: consists of user data streams; it is involved in service process. In Iub transports both RRC and NAS signaling process

Iub OVER ATM Interface Protocol Stack

DC

H

FP

RA

CH

F

P

DC

H

FP

PC

H

FP

NBAP

Q.2630.2

UNI SAAL

AAL5

UNI SAAL

AAL5

ATM

AAL2

Physical Layer

OSI and CPP

Physical

Data Link

Network

Transport

Session

Presentation

Application

AAL5

• AAL5 adapts multicell higher layer signalling PDUs in to ATM format with minimal error detection.

• The AAL5 protocol provides a best-effort data service over an ATM connection .

• Concept introduced by Ericsson on ISS-95 (1995)• Bandwidth efficient transmission of low rate, short and variable

length packets in delay sensitive applications• Several (up to 248) AAL2 user information streams are

multiplexed on the same ATM connection.• Standardized in ITU-T I.366, I.363, Q.2630• Ericsson owns the “AAL2 patent”

• Inventor: Lars-Göran Petersen• Cello supports:

• node internal AAL2 connections• network wide AAL2 connections

• Cello may also act as a pure AAL2 switch

ATM adaptation layer 2

ATM Cells

User 1 User 2 User 3 User 1

AAL2 CPS-packet (I.363.2)

CID LI

UUI HEC CPS-INFOCID LI

HECUUI

CPS-INFO

Channel Identifier Length Indicator

Header Error ControlUser-to-User Indication

Information (Payload)

(8 bits) (6 bits)

(5 bits)(5 bits)

(1-45 octets*)*64 octet option is NOTsupported

CPS-packet header3 bytes

CPS-packet payload

MOM

Operator’s view...

Aal2Sp‘50001’

Aal2ApapFroId=12

AAL2 network address of

a node (A2EA)

CPP node

AESA

List of (AP id, Priority)

‘50002’

(12,1)

‘12345’

(11,1) (13,2)

Aal2RoutingCase

Aal2PathVccTp

Aal2PathVccTp

Aal2PathVccTp

Other node

‘50002’

Aal2PathDistributionUnit

Aal2Ap

Data link

Signalling linkMTP3B or UNI-SAAL

Aal2ApapFroId=11

Aal2ApapFroId=13

UNISAAL

• All UNI-SAAL CEPs are created through management.

• The UNI-SAAL service is provided only on Main Processors (MPs).

• A UNI-SAAL connection provides bidirectional transport of user data end-to-end between two UNI-SAAL Connection End-Points (CEPs).

UNI-SAAL Connection Overview

Q.2630-Introduction

• What is Q.2630 used to do? Q.2630 is used during call set-up and clear down, to

acquire and release resources across the Iub link.

Q.2630 is a bearer independent signaling protocol used to establish, release and maintain, dynamic, on-demand AAL2 connections between AAL2 Service Endpoints. It does not perform call control functionality

NBAP

• NBAP (Node-B Application Part) Signaling protocol responsible for the control of the Node B by the RNC. NBAP is subdivided into: Common and Dedicated NBAP (C-NBAP and D-NBAP), where

• Common NBAP controls overall Node B functionality

• Dedicated NBAP controls separate cells or sectors of the Node B.

Iub IP Protocol Stack

Ethernet

NBAP

RadioNetworkLayer

Control Plane User Plane

IP

UDPSCTP

NTP

TransportNetworkLayer

DCH, HS-DSCH, E-DCH, FACH, PCH and RACH FPs

UDP

Network Synch

Iub over IP

Transport Network Layer-Traffic Plane UDP (User Datagram Protocol) serves Radio

Bearers (Data Bearer) NTP (Network Time Protocol) serves to

synchronize the real time clock of the RBS SCTP (Stream Control Transmission Protocol)

supports multihomed hosts to give service to NBAP (Signaling Bearer)

Why Use SCTP?

SCTP is a reliable transport protocol

Specifically designed for transport of message oriented applications

Acknowledged error free transfer of messages

Detection of data corruption, loss of data and duplication of data

Selective retransmission to correct lost or corrupted data

Heartbeat actively monitors connectivity of session

Resistance to Denial of Service attacks

Supports several streams within a connection (or association)

OVERVIEW OF IUB OVER IP NETWORK

IP network

MMP

RBS

ET

–M

FX

IP address

MP

IP Host

SCTP Host

NBAP Protocol

NBAP-C NBAP-D

SCTP port

NBAP Protocol

NBAP-C NBAP-D NBAP-C NBAP-D

SCTP Host

SCTP port

IP Host

NBAP Protocol

NBAP-C NBAP-D NBAP-C NBAP-D

SCTP Host

SCTP port

IP Host

ET

-M

FX

ET

-M

FX

RNC

Iub over IP (Addressing/Subnetting)UP+Sync

CP

O&M

RBS

UP+Sync

CP

O&M

RBS

UP+Sync

CP

O&M

RBS

UP+Sync

RNCCP

O&M

O&M NetworkOSS / Servers

IP Access Network

Traffic Network

Separated by VLAN IDs

O&M Network

COMPARISON BETWEEN ATM AND IP CONTROL PLANE

• Control plane

Physical Layer

ATM

AAL5

ATM Control Plane

NBAP-C NBAP-D

UNI-SAAL

Physical Layer

IP

SCTP

NBAP-C NBAP-D

IP Control Plane

Ethernet

IP transport and ATM transport MO structure

Management element

equipment

subrack

Slot=2

Pluginunit=1

exchangeterminalIp

IPinterface

IPAccesshostET IPAccesshostGPB

Ethernetswitch=1

Ethernetswitchport=1

Slot=1

Pluginunit=1

Cbu=1

exchangeTerminal=1

Generalprocessorunit=1

Transportnetwork=1

sctpATMport Imagroup

VPItp=vp1

VCItp=vc2072

AAL5TpVCCtp AAL2Qosprofile

AAl2sp unisaalprofile

Transportnetwork=1

Atmtrafficdiscriptor

IP transport mo structure

ATM transport mo structure

01_Iub_RNC_RJBL305_EN_CHND21.mo

02_Iub_EN_UM1893.txt