9370 RNC UA06 Functional Description
9370 RNC UA06 Functional Description
9370 RNC UA06 Functional Description
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9370 RNC
UA06 Functional Description
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1. RNC
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2. support
Functional Architecture 5. Topic/Section is Positioned Here
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1. Functional Architecture
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9370 RNC
UA06 Functional Description
Other comments
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At any time during the training, you can access the acronym list by clicking on the Attachments button at
the top right of the window.
Content:
1. UTRAN Architecture
2. Radio and Network Protocols
3. RNC Functions
Audience
Personnel in charge of network operation.
Objectives
Upon completion of this training, you should be able to situate the RNC in the UTRAN.
Estimated Duration
xx minutes
Let's look first at the objectives of this training. The test at the end allows you to check if these objectives
have been reached.
1 UTRAN Architecture
RNS
Uu Iub Iu-CS
9370 RNC CSCN
BTS
RNS Iur
Iu-PS
Iub
UE
9370 RNC PSCN
BTS
UTRAN is like a gateway between the User Equipment (UE) and the Core Network. It receives data from the
Uu interface and sends it to the Core Network on the Iu interface, and inversely. The Uu interface is the air
interface where the WCDMA technology is used.
To be this gateway, the UTRAN is made up of several Radio Network Sub-Systems (RNSs). Each RNS is made
up of one and only one Radio Network Controller (RNC) and a set of Nodes B.
The RNC provides several interfaces: first the Iub interface towards a Node B, then the Iu-CS and Iu-PS
interfaces towards the Core Network and finally the Iur interface towards another RNC.
The Alcatel-Lucent UTRAN of the UMTS V5.0 comprises the Alcatel-Lucent UMTS RNC, the Alcatel-Lucent
UMTS BTS and the W-NMS for the OAM part. Note that the W-NMS is the equivalent of the OMC-R in the
Alcatel-Lucent solution.
The Alcatel-Lucent UMTS RNC is the 9370 RNC. It is the 3GPP-compliant UMTS RNC developed by Alcatel-
Lucent.
The UMTS 9370 RNC is based on the Multiservice Switch platform (commonly called MSS).
The RNC allows mobility between UMTS and GSM networks.
The Alcatel-Lucent UMTS BTS is the 3GPP-compliant UMTS Node B developed by Alcatel-Lucent. The generic
term BTS designates the Alcatel-Lucent UMTS Internet Base Transceiver Station (Alcatel-Lucent UMTS BTS).
The Alcatel-Lucent RNC is made up of the 9370 RNC and an Alcatel-Lucent Transport Node.
Iub/ Iu-CS
STM-1 STM-1 MSC
Alcatel-Lucent
RNC Iu-PS
Iub/E1 SGSN
ATM Alcatel 9140 ATM
backbone 9370Server
RAN RNC backbone Iur
BTS
Other
STM-1 RNC
Iub/E1
Transport Node
or PoC Itf-R
BTS (optional) Itf-B
BTS
OMC
The main functions of the RNC are to control and manage the Radio Access Network (RAN), the signaling
between the different Core Network components and the Radio Network Subsystem, and the Node Bs and
their corresponding radio resources.
The Alcatel-Lucent RNC is composed of the 9370 RNC and an Alcatel-Lucent Transport Node which is
optional. It depends on the way to connect the Node B to the RNC. The 9370 RNC and the Transport Node
are linked by STM-1. The 9370 RNC will be called simply RNC in the next slides.
The RNC is linked by STM-1 links through an ATM backbone to the MSC and to the SGSN.
To handle handover, one 9370 RNC may be linked to several other RNCs. They can come from other
manufacturers and can pass through the Core Network (the MSC) or not, in case of local Iur with the soft
handovers.
As regards the BTS, there are 2 ways to connect the 9370 RNC to its BTS: either through an ATM backbone
where an STM-1 link is used on RNC side and an E1 link on BTS side or through E1 links. It is the Transport
Node which makes the conversion of STM-1 links into E1 links.
Concerning the operation and maintenance, the 9370 RNC is able to send O&M flows directly on STM-1 links
in which case we will talk about "INBAND Operation and Maintenance". The RNC is also able to send O&M
flows over a dedicated Ethernet cable which is called in this case "OUTBAND operation and maintenance".
Iub/ Iu-CS
STM-1 STM-1 MSC
Alcatel-Lucent
RNC
Iub/E1
9370 RNC
Eth
IP GigE GigE
backbone Itf-R
SGSN
Iu-PS Itf-B
OMC
In addition to ATM, the Alcatel-Lucent RNC supports IP transport on the Iub and Iu-PS interface.
A native IP Iub interface is introduced through a software upgrade and the addition of two 4-ports Gigabit
Ethernet boards on the RNC. No forklift is required and the existing STM-1 boards can be used for any
interfaces that remain on ATM transport.
IP/Ethernet interface is for HSDPA/HSUPA best effort traffic (Interactive and Background).
R99 services and Streaming on HSDPA, newly introduced in release UA06, is transported on ATM on the Iub
interface.
Radio protocols are used to exchange user data and signaling between the UE and the RNC.
Control Control
plane User plane plane User plane
RRC Data Voice RRC Data Voice CSCN
RLC RLC
Logical channels Logical channels
MAC MAC
Transport channels Transport channels
Not
Iub-FP radio Iub-FP
protocols
AAL2 AAL2
Physical Physical
(WCDMA) (WCDMA) ATM ATM
Physical Physical
Physical
channels
Iub
9370
RNC
1500
RNC
Node B
UE
Let’s see an example with the path of the voice across the protocol stacks in the UTRAN.
The voice is received from the Core Network by layer 3. It receives what we call the "Radio Bearer". There
are two planes at this level: the control plane and the user plane. The voice belongs to the user plane and
is not processed at this level. It goes the same for the data coming from the PS Core Network.
Then the Radio Bearer is sent to layer 2. This layer is made up of the Radio Link Control protocol (RLC
protocol) and the Medium Access Control protocol (MAC protocol). The RLC protocol mainly segments and
buffers the data. It also maps the radio bearer on the logical channels. The MAC protocol multiplexes
logical channels and maps them on transport channels.
After, the transport channels are sent to the Node B. At this level, they are processed by the network
protocols to send them on ATM.
These transport channels are received by the Node B which applies the network protocols to retrieve the
data and send it to the physical layer. To give an example, the physical layer applies the scrambling and
channelisation codes, modulates or amplifies the signal to send it on the feeders which are connected to
the antennas.
Next, the data are sent on the air and received by the UE. Its physical layer amplifies, applies the same
code in phase and demodulates the signal and other tasks. At this level, the UE retrieves the transport
channels. Then there are the same protocols as in the RNC.
On the control plane, the same protocols are used for layers 1 and 2. But on the layer 3, there is another
protocol called Radio Resource Control (RRC protocol). It is the highest protocol in the control plane. It
terminates all the signaling with the UE.
All Rights Reserved © Alcatel-Lucent
2 Radio and Network Protocols
Radio Protocols: Evolution to IP Les éléments ont été bidouillés
10
Radio protocols are used to exchange user data and signaling between the UE and the RNC.
RLC RLC
Logical channels Logical channels
MAC MAC
Transport channels Transport channels
Not
Iub-FP radio Iub-FP
protocols
UDP/IP UDP/IP
Physical Physical
(WCDMA) (WCDMA) Ethernet Ethernet
Physical Physical
Physical
channels
Iub
9370
RNC
1500
RNC
Node B
UE
Don’t forget that from release UA06, IP over Ethernet for HSPA traffic (Data Services) is still supported, at
the transport layer, but not for other types of services (including Streaming on HSPA). Indeed, these
services continue to use ATM as indicated previously.
Iu-FP/
AAL2
Iu-CS
NBAP/ Iub-FP/
AAL5 AAL2 MSC
Iub
RANAP/
RNC AAL5
Iu-PS
Node B Iur-FP/
AAL2
SGSN
Iur
RNSAP/
AAL5 Iu-FP/
AAL5
Network protocols
in the user plane
The network protocols are used for the exchange of signaling and traffic data between the RNC and the
Node B (on the Iub interface), between two RNCs (on the Iur interface) and between the RNC and the CN
(on the Iu-CS and Iu-PS interfaces).
As for the radio protocols, there are two planes: the control plane and the user plane.
In the control plane, the first network protocol is the NBAP protocol. This protocol is used to exchange
specific signaling between the RNC and the Node B, like the addition of a new radio link. A second protocol
is the RNSAP protocol which is used to exchange specific signaling between two RNCs, mainly in case of
soft handover where 2 RNCs are involved. The last protocol is the RANAP protocol which is used to
exchange specific signaling between the RNC and the Core Network, like the release of a call for example.
All these protocols are conveyed on AAL5.
In the user plane, the Iub-FP and Iur-FP protocols are used to convey not only the traffic data but also
radio signaling (i.e RRC messages and NAS signal). On the other hand, the Iu-FP protocols are used to
convey traffic data only.
Note that PS traffic is conveyed on AAL2 on the Iub and Iur interfaces and on AAL5 on the Iu-PS interface.
An AAL2/AAL5 conversion is necessary for PS traffic in the RNC.
3 RNC Functions
RNS
Iub
Iu-CS
9370
CSCN
RNC
BTS
Iur
RNS
Iu-PS
Iub
UE 9370
PSCN
RNC
BTS
End of Module
Functional Architecture
3FLXXXXXXCAAWZZA
At any time during the training, you can access the acronym list by clicking on the Attachments button at
the top right of the window.
Content:
1. Functional Block Description
2. Signal Flows inside the RNC
In this course, we are going to describe each functional block of the RNC.
Then we will see the signal flows inside the RNC.
Audience
Personnel in charge of network operation.
Objectives
Upon completion of this training, you should be able to describe the functional architecture
of the RNC
Estimated Duration
xx minutes
Let's look first at the objectives of this training. The test at the end allows to check if these objectives
have been reached.
First, let's discover the functional blocks of the RNC and what they are used to.
RNC
CONTROL NODE
Control Plane Processing:
Transmission • RRM Transmission
Block • RRC Block
• xxAP
Iur
Network
interface
Iu
Network
Internal interface
switching
Network
interface
NBAP, RANAP,
RNSAP, ALCAP Iub
AAL5 based
C-Plane Protocols INTERFACE NODE
Iux FP, AAL2 based High Touch Bearer Functions:
U-Plane Protocols • Header Compression • PDCP
• RLC • Macro Diversity
RRC Protocol • MAC • FP Termination
Internal Control
Packet
Server
The RNC includes several types of hardware modules, each performing specific functions.
A first hardware module is the CP. The CP is the Control Processor. It manages and controls the system and
network functions and stores the data on its hard disk.
Then the RNC supports boards responsible for the transmission links. Each board has 16 ports for optical
connectors either in STM-1 or OC-3.
That's why they are called 16p OC-3/STM-1. This type of board connects the RNC with other Network
Elements for Iu, Iur and Iub connectivity.
Next we find the Packet Server or Dual Core Packet Server Functional Processor boards (which are also
called PS-FP or DSCP boards). These boards manage the bearer processing functions (for the user plane) as
well as the control plane processing. In fact, we could say that the PS-FP boards manage all the radio and
network functions of the RNC but they don't perform the management of the transmission links.
So the PS-FP boards are responsible for the Traffic Management with the Call Processing and the radio
functions, the management of the Radio Access Bearer at the MAC and RLC layers, the Network Interface
signaling with the SS7 protocol and finally the OAM Management.
Also optionally RNC could have two 4-port Gigabit Ethernet boards to provide the IP over Ethernet
connectivity on Iub and Iu-PS.
Finally the RNC includes an internal switch called "fabric module" or "switch Fabric". There are 2 fabric
modules working in load sharing, each one at 56.7 Gigabits per second. Each of these modules is
dimensioned to be able to process alone the maximum load of the RNC in case one of them is in failure.
Software
Downloading
16p OC3/STM1 FP
Disk Management Fabric
Module
ATM Services
Shelf Manager
4p GigE FP
Ererer
Rererez
Rerezrzer
Reserve
Ererez
Erasers
Erase
Erere
Eraser
ererer
Maintaining
Routing Tables
WMS
Link to OA&M
(Ethernet 10/100 baseT)
The Control Processor (CP) manages all the resources of the RNC, its interfaces with the OMC-R and
contains a local disk for loads and logs.
The CP has a 1+1 redundancy scheme and uses a proprietary operating system built on VxWorks®.
The hard disk in the CP module has a capacity of 20 GigaBytes for the storage of the firmware packages,
Provisioning Data, Software, Operational Files, Logs, Call Trace files.
Interface Node
CP
modules
Packet Server FP
Radio
Bearer
AAL5 ATM cells Protocol
PMCs
Converter TCP / IP / AAL5
16P PMC
OC-3/
STM-1 FP
AAL5 ATM cells Traffic
Management
Unit PMCs
AAL2 ATM cells
FP
modules
The Packet Server Functional Processor module (or just PS-FP) is a board with 6 internal processors,
commonly called PMCs as those packet server functional processors are based on the internal open
architecture of PCI Mezzanine Cards.
Then each PS-FP board hosts 6 PMCs.
The PS-FP module is responsible for radio protocol handling (with the MAC, RLC and PDCP protocols) and
soft handover management. It performs the AAL2 function with segmentation and re-assembly as well as
the conversion of AAL2 into AAL5 for internal use or for Packet calls. The PS-FP module also manages the
termination of network protocols (such as RANAP, RNSAP, NBAP and ALCAP). Furthermore, it supplies RRM
support with the RRC protocol and algorithms for the QoS management, the call admission, the mobility or
the radio admission control. And finally it assures the IP routing for the OAM Management.
From release UA05.1.2, two types of Packet Server boards exist: PSFP and Dual Core Packet Server.
Packet Server FP #01 Packet Server FP #02 Packet Server FP #03 Packet Server FP #12
PMC PMC PMC PMC PMC PMC PMC PMC PMC PMC PMC PMC
Master PC TMU Master PC TMU PC OMU NI PC TMU TMU
...
PMC PMC PMC PMC PMC PMC PMC PMC PMC PMC PMC PMC
RAB RAB RAB RAB RAB RAB RAB RAB RAB RAB RAB RAB
We have just seen that each PS-FP module houses 6 PMC processors.
The PMCs are spared within each PS-FP module so that the failure of a single computing element could not
break off an entire PS-FP module.
In any configuration of RNC, you find 2 PMC-Master, 2 PMC-NIs and 2 PMC-OMUs: one is active, the other is
in standby for redundancy purposes. In the case a PS-FP board manages a PMC-Master, we call it a Master
PS-FP.
Each PS-FP board also includes a PMC-PC for the conversion of AAL2 into AAL5.
The number of PMC-RABs and PMC-TMUs depends on the configuration of your RNC and obvioulsy, the more
PMCs, the highest the RNC capacity.
16P 4P
Packet
OC-3/ GigE
CP Server
FP STM-1 FP
CP3
Each RNC contains 2 fabric modules working in load sharing and responsible for the internal ATM routing
between boards. They are located one above the other at the rear side of the shelf assembly.
A fabric module is dimensioned to work alone in case of failure of the other one. Therefore one fabric
module is able to support the whole traffic load of the RNC.
A single fabric module is a 16x16 non-blocking switch which provides each input and output port with a 3.2-
Gbit/s bandwidth, for a total throughput of 56.7 Gbit/s.
The cell switching is connectionless and self-routing. In addition, the RNC backplane cells are 68-byte long
with a 7-byte header. The ATM cell (of 53 bytes) is then included in the 60-byte payload.
Fabric Module
Packet
Control
Server
Processor FP
CP
Connection scheduler
PoC
Iu
Iub Iub Core
Class scheduler
Network
Node B
16 optical port interfaces
Other
16pOC-3/STM-1 FP RNC
STM-1
Iur
9370 RNC
Node B
The 16-port OC-3/STM-1 is a Functional Processor module that provides connectivity inside the RNC.
This FP module is the ATM interface module of the RNC for the Iu, Iub and Iur interfaces.
Note that all ports of the board are either of OC-3 type or of STM-1 type.
We will see later the recommended configurations of those optical ports and the protection solutions that
are enabled at port level.
Fabric Module
New Slide Packet
Control
Server
Processor FP
CP
IP differentiated services
Iu-ps
Iub Iub Core
Class scheduler
Network
4p GigE
Ethernet
Node B
9370 RNC
The 4-port Gigabit Ethernet board is a Functional Processor module that provides IP connectivity.
This FP module is the Ethernet interface module of the RNC for the hybrid Iub and Iu-PS interfaces.
This board performs IP encapsulation over Ethernet and is able to manage IP differential services.
In this section, we are going to see by which blocks different signals are processed.
This section will give you a global view of the RNC and will help you to understand how each block
operates.
AAL2 AAL2
16p Fabric Module
OC-3
AAL5 AAL2
Node B
Control Plane:
NBAP AAL2 AAL5 AAL5
ALCAP
Iu Interface
All Rights Reserved © Alcatel-Lucent 2008
In this first example, a user is establishing a voice call while the mobile is sending traffic data to the RNC.
So this traffic has to be transferred to the Circuit core network.
You can see that the signal coming from the mobile through the Node B is received by the transmission
block in the STM-1 board in AAL2 format.
Then the data is sent through the internal fabric module to the PS-FP board. This board first converts the
ATM cells from the AAL2 format into the IP format which is understandable by the other PMCs.
Still inside the PS-FP board, the data is sent to be processed in the PMC-RAB in order to extract the voice
from the DCH transport channel.
Once at the output of the PMC-RAB, the voice is simply forwarded to the MSC in AAL2 format.
User Plane:
Dedicated channels
Iub
(traffic, control)
Common channels
AAL2 AAL2
16p Fabric Module
OC-3
AAL5 IP
Node B
Control Plane:
NBAP AAL2 AAL5 AAL5
ALCAP
Iu Interface
All Rights Reserved © Alcatel-Lucent 2008
Here is an example of packet call such as web browsing. Therefore the data has to be sent to the packet
Core Network.
In this example, the data is sent by the mobile. So the Node B receives the transport channel from the
mobile. Note that data can be carried over a dedicated or a common transport channel depending on the
amount of traffic to carry.
Next, the Node B forwards the transport channel over ATM in AAL2 format as always for the user plane on
the Iub interface.
As for a circuit call, the RNC receives the data through the STM-1 board (or 16 port OC-3) and processes this
data in the PS-FP board. Of course the signal is still going through the fabric module which interconnects
the different boards.
In the same way as voice, the AAL2 format is converted internally into IP to be understood by other PMCs.
The IP packets are then extracted from the transport and logical channels inside the PMC-RAB. In this PMC,
some specific protocols like GTP-U or UDP may be applied before forwarding the useful data to the SGSN.
In order to carry the IP packets from the RNC to the SGSN, you can notice that the data is still in AAL5
format at the output of the 16p OC3/STM-1 board.
User Plane:
Dedicated channels
Iub
(traffic, control)
Common channels
IP IP
4p Fabric Module
GigE
AAL5 IP
Node B
Control Plane:
NBAP IP IP
ALCAP
GTP RANAP
NRT
U-Plane C-Plane
Iu Interface
All Rights Reserved © Alcatel-Lucent 2008
User Plane:
Dedicated channels
Iub
(traffic, control)
Common channels AAL2
AAL2 AAL2
16p Fabric Module
OC-3
AAL5 AAL2
Node B
Control Plane:
NBAP AAL2 AAL5 AAL5
ALCAP
Iu Interface
All Rights Reserved © Alcatel-Lucent 2008
This example shows a dedicated signalling between the RNC and a UE. The RNC receives the message sent
by the mobile. This message can be for example a measurement report sent when the UE is able to receive
a cell with a good quality.
The message is mapped on the logical Dedicated Control Channel (DCCH). This logical channel is then
mapped, by the MAC protocol, on the Dedicated transport Channel (DCH).
As the message goes through the air interface, it is transported by the user plane of the network protocol.
That means this USER signalling is seen as useful data between the Node B and the RNC, that's why it is
carried in AAL2 format.
Inside the RNC, the transmission block receives the STM-1 frame and extracts the ATM cells from this frame
in AAL2 format. Then the frame is sent to the PS-FP board through the "fabric module".
Inside the PS-FP board, as usual, the PMC-PC converts AAL2 into IP. Then the PMC-RAB demultiplexes the
logical channels from the transport channel with the MAC protocol and extracts the signalling radio bearer
from the logical channel thanks to the RLC protocol.
Finally this RRC message is sent to the PMC-TMU to be understood by the RRC protocol.
User Plane:
Dedicated channels
Iub
(traffic, control)
Common channels AAL2
AAL5
AAL2 AAL5
16p Fabric Module
OC-3
AAL5 AAL5
Node B
Control Plane:
NBAP AAL2 AAL5 AAL5
ALCAP
Iu Interface
All Rights Reserved © Alcatel-Lucent 2008
Let's now take the example of a network signalling, more precisely a signalling message between 2 network
elements.
We have illustrated here how an NBAP message sent by the BTS is processed in the RNC. Let's suppose this
message is the response of the BTS in a "Radio link establishment" procedure.
The message is received, first, by the transmission block on an STM-1 link.
As it is network signalling, the message is never sent on the air interface. So there is no channel to
demultiplex. This is the reason why the NBAP message is carried directly over ATM.
Moreover, as the NBAP message is carried over AAL5 like any other network application protocol, there is
no need to perform an AAL2-IP conversion.
So, the PMC-TMU simply receives the NBAP message and processes it with the NBAP protocol.
End of Module