03 MGW for MSSread.pudn.com/downloads207/doc/975609/material_from_nokia/03_MGW for MSS.pdfOptional upgrades in U3A and U3B are the new WCDMA STM-1/OC-3 and GSM STM-1/OC-3 configuration

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3G Core Network

MGW for MSS (U3B) Training Document

MGW for MSS (U3B)

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Contents


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Contents

1 Objectives............................................................................................. 5

2 Overview of IPA2800 MGW for 3G-MSS.............................................. 6 2.1 Media gateway mechanics..................................................................... 7 2.2 New features and Hardware in U3B....................................................... 8 2.2.1 Phasing of features in Nokia MGW ........................................................ 8 2.2.2 U3B Features......................................................................................... 9

3 Nokia MGW Functional Units ............................................................ 13 3.1 Control Function Units.......................................................................... 14 3.1.1 CACU, Control and Administrative Computer Unit ............................... 14 3.1.2 CM, Central Memory............................................................................ 15 3.1.3 ISU, Interface Control and Signalling Unit ............................................ 15 3.1.4 SPMU, Signal Processing Management Unit ....................................... 17 3.1.5 VANU, Voice Announcement Unit ........................................................ 18 3.1.6 SWU (ESA24 or ESA12), Ethernet Switch ........................................... 18 3.2 O&M Function Units............................................................................. 20 3.2.1 OMU, Operation and Maintenance Unit and its subunits ...................... 20 3.2.2 NEMU, Network Element Management Unit and its subunits............... 21 3.3 Signal processing units ........................................................................ 23 3.3.1 Transcoding unit .................................................................................. 23 3.4 Network Element Interface Units.......................................................... 24 3.4.1 NIP1..................................................................................................... 25 3.4.2 NIS1 / NIS1P ....................................................................................... 26 3.4.3 NIWU................................................................................................... 27 3.4.4 IP NIU, IP Network Interface Unit Fast / Gigabit Ethernet..................... 28 3.4.5 IWS1E/T .............................................................................................. 29 3.5 Switching and Multiplexing Units.......................................................... 31 3.5.1 SFU, Switching Fabric Unit .................................................................. 32 3.5.2 MXU, Multiplexer Unit .......................................................................... 33 3.5.3 A2SU, AAL 2 Switching Unit ................................................................ 34 3.6 Timing, power distribution and HMS..................................................... 35 3.6.1 TBU, Timing and Hardware Management Bus Unit .............................. 36 3.6.2 HMS subsystem................................................................................... 39 3.6.3 Power Distribution Subsystem ............................................................. 41 3.7 EHU, External Hardware Alarm Unit .................................................... 43 3.7.1 EXAU, External hardware alarm panel................................................. 43 3.7.2 CAIND, Cabinet alarm indicator ........................................................... 43

4 MGW Hardware Configuration .......................................................... 44

5 Nokia MGW Interfaces ....................................................................... 51 5.1 Physical connections in Nokia MGW.................................................... 51 5.2 ATM Backbone in Nokia MGW............................................................. 52 5.3 IP Backbone in Nokia MGW................................................................. 52

MGW for MSS (U3B)


5.3.1 Separating signalling from user plane .................................................. 53 5.4 TDM Backbone in Nokia MGW............................................................. 54 5.5 Nokia MGW control interface................................................................ 54 5.5.1 MGW control protocols (MEGACO/H.248) ........................................... 54 5.6 Iu interface in Nokia MGW ................................................................... 55 5.7 A-interface in Nokia MGW.................................................................... 56 5.8 Interface towards PSTN and other TDM-based networks in

Nokia MGW.......................................................................................... 56

Objectives


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1 Objectives After completing this module, the student should be able to:

• List the main functions of the MGW for MSS

• Explain the main functions of each functional unit.

• List the redundancy principles for the function units.

• Identify the interfaces implemented in the MGW.

• Explain the MGW hardware configuration

MGW for MSS (U3B)


2 Overview of IPA2800 MGW for 3G-MSS The 3rd Generation mobile networks will accelerate the shift towards supporting mass-market IP-based applications that has started with 2nd Generation systems (GSM, US-TDMA). The wireless market is undergoing a period of rapid change in competition, services and underlying technology, making the choice of the network system complex. With Nokia 3G solutions, operators reduce risks by using proven concepts. Mobile networks will continue to evolve, from today to the 3G launch and onwards, to increase the range of available services and service capabilities.

Figure 1 MGW in MSC Server Environment The Nokia Multimedia Gateway product can be used for transmitting and

SGSN

RNCRNC

GSM

BSCBSC

WCDMA MGWMGW

ExternalIP networks

IP/ATM/TDMBackbone

MGW

PSTN/ISDN

Other PLMN

HLR

GCS -GatewayControl Server


MSC ServerMSC Server

GGSN

A

A

Iu-CS

SITGTRANH.248 H.248

BICC CS-2, SIP-T

IN/SCE APSE

SGSNSGSN

RNCRNC

GSM

BSCBSC

WCDMA MGWMGW

ExternalIP networks

IP/ATM/TDMBackbone

MGW

PSTN/ISDN

Other PLMN

HLR





MSC ServerMSC ServerMSC ServerMSC Server

GGSN

A

A

Iu-CS

SITGTRANH.248 H.248

BICC CS-2, SIP-T

IN/SCE APSE

Overview of IPA2800 MGW for 3G-MSS


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converting the user plane traffic in both circuit-switched core networks and All-IP Mobility Core Networks as a border element between different kinds of networks. The Multimedia Gateway consists of several functional elements configured under the gateway architecture. A number of different configurations of the Multimedia Gateway can be used depending on the services required by the operator. The main functions of the Multimedia Gateway are:

• to adapt the conventional signalling (control plane) between MSC server or Gateway Control Server (GCS) and different network interfaces.

• to connect the user data (user plane) from ATM/IP backbone into radio access network or circuit switched networks. Media resources are under control of Gateway Control Server (GCS), GCS or MSC server via H.248 (MEGACO) protocol.

• to provide tones and announcements to end users.

• to perform the transcoding and signal processing for the user plane

when needed. Typically, one control network element (CPS, GCS or MSC server) handles several gateways. Therefore, Nokia Multimedia Gateway provides the possibility to create virtual gateways in one physical gateway element so that it offers media resources to several controlling elements. This multihosting functionality in the gateway gives operators flexibility to utilise the network elements optimally, depending on the network architecture.

2.1 Media gateway mechanics

The mechanical construction of the IPA2800 network elements is based on M2000 mechanics platform, which follows a standard hierarchy:

• Cabinets

• cooling and power supply equipment

• subracks

• plug-in units

• internal cables.

The equipment of the IPA2800 network elements is housed in IC186 or IC186-B cabinets. One cabinet has space for the cabinet-specific power

MGW for MSS (U3B)


distribution equipment, four subracks and subrack-specific cooling equipment.

All IPA2800 network elements use three types of subracks, called SRA1-A, SRA2-A and SRBI-B. The SRA1-A is only used in the first two positions in the A cabinet, all other positions use the SRA2-A. The only difference between SRA1-A and SRA2-A two subracks is that the SRA2-A integrates more of the subrack's internal cabling, such as signals from the MXUs to tributary units, into its backpanel. SRBI-B is a equipped behind the SRA1-A and SRA2-A subracks to provide modular backplane connections.

The total number of different plug-in unit types used in a single IPA2800 network element is approximately 15. The plug-in units are generally connected to the other parts of the system by means of backplane connectors. Some of the connections, however, are made from the front panels, normally by means of standard RJ-45 connectors. The plug-in units of the IPA2800 network elements are designed to support hot swapping. The plug in units are equipped with various LED indicators for monitoring the unit's condition.

2.2 New features and Hardware in U3B

There is only one mandatory hardware upgrade from U2 to U3A or U3B: All CDSP, -A, -B plug-in units must be upgraded to CDSP-C. CDSP-C implements the TCU functional unit.

Ina addition for U3B, all MX622-B plug-in units must be upgraded to MX622-C. The MX622 implements the MXU functional unit. For detailed information and instructions on how to carry out the upgrade, see Hardware Upgrade Guide for MGW U2 to U3A and U3B.

Optional upgrades in U3A and U3B are the new WCDMA STM-1/OC-3 and GSM STM-1/OC-3 configuration options which are implemented with the addition of the new interface unit IWS1E/T.

2.2.1 Phasing of features in Nokia MGW

Nokia Multimedia Gateway for both MSC Server and IP Multimedia Subsystem environment is an evolution step from Multimedia Gateway belonging to 3G MSC. All features from previous releases and earlier architectures are also available in later releases.

Different functionalities become available in MGW as follows:

• U2: Functionality required by both 3G MSC and the first release of Nokia MSC Server system.



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• U3A: STM-1/OC-3 interface for TDM use in MSC Server system.

• U3B: Additional functionality for the MSC Server system release 2 including possibility to use the same network element also in IP Multimedia Subsystem.

• U3C: Introduces Ater and Wideband AMR functionalities

• U4: New features for both the MSC Server environment and IP Multimedia Subsystem environment for the MSC Server system release 3

2.2.2 U3B Features

• ABNF coding for H.248 protocol.

− The U2 release only supports ASN.1 (binary) coding for H.248 messages. ABNF (text) is provided in U3B as an alternative method for helping multi-vendor interoperability. ABNF is also applied in the MGW for IMS environment.

• Mb interface support.

− This interface is needed in IP Multimedia Subsystem environment. The Mb interface connects the IP Multimedia Subsystem (IMS) to MGW, which provides the interconnection with other supported multi-access VoIP interfaces and BSS, RAN, PSTN, or IP, ATM, or TDM backbone.

• Text Telephony Service (TTY) for 3G calls.

− Text Telephony is a feature that enables text-based communication over a speech bearer. This is mainly intended for hearing impaired people. The text is transmitted through ordinary speech traffic channels

• U3B TrFO

− With Transcoder-free Operation (TrFO), the intention is to completely remove the unnecessary transcoding from the speech path. This is achieved with an out of band signalling performing the coded negotiation and selection throughout the network. Optimally, this means that speech transcoding is only performed in peer UEs (user equipment, 3G terminal).

TrFO is standardised for 3G calls only (that is, calls via UTRAN). TrFO provides optimised speech quality and enables savings in the transmission capacity in the core network. Only compressed speech samples are transmitted over the ATM/IP networks

MGW for MSS (U3B)


• Acoustic Echo Cancellation

− Acoustic echo is generated in the uplink direction due to the acoustic coupling from the ear-piece to microphone of the User Equipment (UE). Acoustic echo is removed by a built-in acoustic echo control device of the UE.

Sometimes the UE functionality is not sufficient, and therefore AEC functionality is provided on the network side by MGW.

To deal with the echo generated in the downlink direction, there is an echo canceller in MGW. The echo canceller memorizes the voice samples sent to the PSTN and then compares the samples to the voice samples received back from the PSTN. These speech samples (containing the echo) are modified by the echo canceller to prevent the echo effect from being passed back to the mobile.

In the uplink direction, the PSTN phone user hears an acoustic echo as his/her voice is transmitted back from the mobile phone and he/she experiences delay generated both in core network and radio network. To deal with this echo, the mobile phone is equipped with a built-in acoustic echo canceller and AEC functionality is provided on the network side by MGW.

• IPv6 support U3B

− MGW supports IPv4/IPv6 as dual stack implementation in U3B for control and user plane. The dual stack implementation is a very important transition mechanism. This is the simplest and easiest way to enable communication between the IPv4 and IPv6 entities. A network element supporting both stacks can communicate with an IPv4 or IPv6 peer entity.

• Measurement Management GUI.

− This feature enables an easy to use graphical measurement handling (starting and stopping of the measurements). In the U2 MGW starting and stopping the measurement was managed only by MML. Statistics reports were directed automatically to NEMU where browsing of the reports was managed by the NE Measurement Explorer application.

In the U3, the measurement handling can be managed via a new graphical user interface. An MML interface can be used, even if the new GUI is available. This feature is used for managing the measurement provided by Common Statistics in IPA2800 Platform. The measurements are used for monitoring of for example:



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computer unit processor load

computer unit availability

statistics of ATM and STM interfaces

application measurements in MGW

• Fault Management GUI.

− The Fault Management GUI of MGW Element Manager allows the user to monitor alarm situations (that is, viewing and cancelling active alarms, viewing alarm history, modifying alarm settings and controlling external alarms and alarm outputs).

The co-operation between different operating functions can be arranged more efficiently with the GUI applications than by using the traditional MMLs. The MGW EM user is able to change quickly from the configuration view to the alarm view. This reduces the time spent on finding and correcting the fault situation in MGW.

• TDM to TDM semi-permanent connections

− Previously only semi-permanent ATM-ATM connections were possible in MGW. Now it is also possible to use semi-permanent TDM-TDM connections to for example:

provide a transparent through-connection for the PBX LAPD channels

route the Gb interface (between BSC and SGSN) semi-permanently through MGW

− route the O&M traffic between BSC and NetAct semi-permanently through MGW.

• Support for Network subsystem configuration tool

− The NSS configuration tool, Nokia Configuration Management Data Mediator (CMDM) is an optional functionality, and requires a separate NEMU computer unit, Medium NEMU Server hardware.

CMDM provides the operator with an opportunity to reduce network planning costs and ease network planning. For example, when configuring a bearer independent CS core network environment (Nokia MSS system), CMDM provides easy access to configuration data and tools for adding new MGWs to a MSS or for modifying existing configuration.

The network element's configuration data can be uploaded faster, with less work hours, and without affecting the capacity or performance of the network element. The possibility to download configuration data to the NE makes

MGW for MSS (U3B)


network planning easier, and less on-site work is needed. CMDM also produces valuable network configuration documentation and information for optimization decisions, and an interface for comparing configuration data between NEs.

Nokia MGW Functional Units


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3 Nokia MGW Functional Units Functionality is distributed to a set of functional units capable of accomplishing a special purpose. These are entities of hardware and software or only hardware. Units are connected to the ATM-based switching matrix (SFU) either directly (in case of units with high traffic capacity) or via multiplexer unit MXU (in case of units with lower traffic capacity).

Figure 2 Functional units in Multimedia Gateway

MGW for MSS (U3B)


3.1 Control Function Units

3.1.1 CACU, Control and Administrative Computer Unit

Purpose: The CACU controls the ATM switching fabrics and establishes connections for calls. Its ATM switching management functions comprise:

• Establishment of both internal and external connections via the SFU, including ATM circuit hunting and address analysis.

• Management and control of the SFU, A2SU and MXU

• Transmission resource management.

Redundancy: 2N

Type: Computer unit

Plug-in Unit: CCP10 / CCPC2-A Control Computer, Pentium III

Interfaces: ATM interface to MXU

Location: CAMA subracks 1-2, 1 unit per subrack

Figure 3 CACU



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3.1.2 CM, Central Memory

Purpose: The CM serves as the central data storage and distribution facility in the exchange. It also handles the centralised part of the common channel signalling, for example, digit analysis.

Redundancy: 2N

Type: Computer unit

Plug-in Unit: CCP10 / CCPC2-A

Control Computer, Pentium III



Figure 4 CM

3.1.3 ISU, Interface Control and Signalling Unit

Purpose: The ISU is responsible for core network emulation and BSS signalling

MGW for MSS (U3B)


emulation towards the MSC. Its tasks include the following:

• Processing of the Message Transfer Part (MTP) and Signalling Connection Part (SCCP) of both narrowband and wideband SS7 signalling

• All message handling and processing functions related to the signalling channels connected to it.

Redundancy: N+1

Type: Computer unit

Plug-in Unit: CCP10 Control Computer, Pentium III


Location: 1 unit in each of CAMA subracks 2-4 and all CAMB, CAMC subracks

Figure 5 ISU



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3.1.4 SPMU, Signal Processing Management Unit

Purpose: The SPMU controls the allocation of the MGW's DSP and CDSP computer resources.

Redundancy: 2N

Type: Computer unit

Plug-in Unit: CCP10 / CCPC2-A Control Computer, Pentium III



Figure 6 SPMU

MGW for MSS (U3B)


3.1.5 VANU, Voice Announcement Unit

Purpose: The Voice Announcement Unit (VANU) controls the announcement function of MGW. It stores the individual speech samples, constructs complete announcements from them and sends them to the DSP units for further processing.

Redundancy: None or load sharing

Type: Computer unit

Plug-in Unit: CCP10 Control Computer, Pentium III



Figure 7 VANU

3.1.6 SWU (ESA24 or ESA12), Ethernet Switch

The SWU (Switch Unit) refers to the LAN switch equipment implemented as ESA24 or ESA12 in the MGW.



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3.1.6.1 ESA24, Ethernet Switch

Purpose: The ESA24 is an Ethernet switch, which provides physical LAN/Ethernet interfaces for connections between NEMU and the other units of the exchange.

Redundancy: None

Type: Sub-unit to NEMU

Plug-in Unit: ESA24 Ethernet Switch

Interfaces: LAN/Ethernet to OMU, NEMU and site LAN

Location: 1 Unit in CAMA subracks 1 and 3

3.1.6.2 ESA12, Ethernet Switch

Purpose: The ESA12 is an Ethernet switch, which provides physical LAN/Ethernet interfaces for connections between NEMU and the other units of the exchange.

Redundancy: None

Type: Sub-unit to NEMU

Plug-in Unit: ESA12 Ethernet Switch

Interfaces: LAN/Ethernet to OMU, NEMU and site LAN

Location: 1 Unit in CAMA subrack 1

MGW for MSS (U3B)


Figure 8 ESA 24

3.2 O&M Function Units

3.2.1 OMU, Operation and Maintenance Unit and its subunits

Purpose: The OMU handles all the MGW's crucial upper-level system maintenance functions, such as hardware configuration management, Hardware Management System (HMS) supervision and the associated centralised recovery functions. In the event of a fault, the OMU automatically activates appropriate recovery and diagnostics procedures within the MGW. It also serves as an interface between the NEMU and the other units of the exchange. The OMU has dedicated storage devices, which house the entire system software and the event buffer for intermediate storing of alarms, along with the radio network configuration files.

Redundancy: 2N

Type: Computer unit, with a dedicated storage device unit as a sub-unit.

Plug-in Unit: CCP10 / CCPC2-A



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Control Computer, Pentium III

Interfaces: ATM virtual channels to MXU LAN/Ethernet via SWU (ESA24/12) to NEMU Duplicated Small Computer Systems Interface (SCSI) Service Terminal interface Multiplexer Interface Duplicated Hardware Management System (HMS) interface


Figure 9 OMU

3.2.2 NEMU, Network Element Management Unit and its subunits

Purpose: The NEMU provides the following facilities: • local user interface • interface towards the higher level network management

system • O&M functionalities which are not handled by other

computer units of the MGW, including post-processing of performance and fault management data, as well as SW upgrade support

• peripheral device control.

MGW for MSS (U3B)


The NEMU is equipped with storage devices for storing measurement and statistical data, and an Ethernet hub with 12 or 24 physical LAN interfaces for connections to the upper-level network management system and the site LAN. Both facilities are implemented as separate plug-in units and described in separate sections which follow this one.

Redundancy: None

Type: Computer unit, with dedicated storage devices and the Ethernet Switch unit (ESA24/12) as sub-units.

Plug-in Unit: MCPC2-A / MCPC2 Management Computer, Pentium III

Interfaces: Small Computer Systems Interface (SCSI) LAN/Ethernet to NMS, OMU and Site LAN via SWU (ESA24/12) * LAN/Ethernet to OMU via SWU (ESA24/12) * USB (for future use) Mouse Keyboard VDU LPT *) A cabinet is configured with either ESA24 or ESA12. ESA12 is used in older deliveries.

Location: 1 unit in CAMA subrack 1



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Figure 10 NEMU

3.3 Signal processing units

3.3.1 Transcoding unit

This category features only one functional unit type, the Transcoding Unit.

Purpose: The TCU includes a number of signal processors whose main functions are: • transcoding, that is, speech signal conversion between the coded format used in the WCDMA Radio Access Network and the PCM format used in the GSM network. • signal level control • discontinuous transmission. All DSPs of the unit can be freely allocated within the MGW.

Redundancy: SN+

MGW for MSS (U3B)


Type: Signal processing unit with no sub-units

Plug-in Unit: CDSP / CDSP-B / CDSP-C for MGW CDSP-C for TDM optimised MGW configuration Configurable Dynamic Signal Processing Platform


Location: In CAMA there are 7 units per subrack, in CAMB+CAMC for MGW there are 8 units per subrack, and in CAMB+CAMC for TDM optimised MGW configuration there are 5 units per subrack.

Figure 11 TCU locations

3.4 Network Element Interface Units

These units serve as the trunk network interfaces of the exchange and execute physical layer and ATM layer functions, such as policing, statistics, Operation Administration Maintenance (OAM), buffer management and scheduling. The category comprises the following units:



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• NIP1, Network Interface Unit PDH • NIS1, Network Interface Unit STM-1 • NIWU, Network Interface Unit TDM • IP NIU, can be either IPFE/IPFEP, IPGE/IPGEP or IPGO/IPGOP • IWS1E/T, Network Interface Unit STM-1/OC-3

Each network interface unit contains more than one physical interface.

3.4.1 NIP1

Purpose: This ATM network interface unit contains PDH E1/T1/JT1 interfaces with Inverse Multiplexing for ATM (IMA) function, which allows for flexible grouping of physical links to logical IMA groups.

Redundancy: None

Type: Signal processing unit

Plug-in Unit: NI16P1A ATM Network Interface 16 x PDH E1/T1/JT1

Capacity/ performance:

Sixteen physical PDH electrical interfaces, each with a bandwidth of:

• 2048 kbit/s (E1) or • 1544 kbit/s (T1/JT1)

Interfaces: ATM interface to MXU Clock reference output to TSS3

Location: For WCDMA E1/T1/JT1 only: three optional units in CAMA subracks 3 and 4 and in all CAMB and CAMC subracks

MGW for MSS (U3B)


Figure 12 NIP1

3.4.2 NIS1 / NIS1P

Purpose: NIS1 provides SDH STM-1 interfaces and handles bit timing, line coding and timing recovery. It is typically used in connections between the MGW and the RNC.

Redundancy: NIS1: None NIS1P: 2N

Type: Networking Interface unit

Plug-in Unit: NI4S1-B Network Interface 4 x 155 Mbit/s STM-1


Four physical SDH STM-1 interfaces, with a bandwidth of 155,52 Mbit/s for each

Interfaces: ATM interface to SFU Clock reference output to TSS3

Location: Up to one unit in each of CAMA subracks 1 and 2 Up to two units in each of CAMA subracks 3 and 4 Up to two units in each of CAMB subracks 1–4



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Figure 13 NIS1/NIS1P

3.4.3 NIWU

Purpose: This ATM network interface unit contains TDM E1/T1/JT1 interfaces, which carry traffic at the A interface, between the MGW and the MSC. It also performs the user plane conversion between the TDM format and the ATM format.

Redundancy: None

Type: Network Interface unit

Plug-in Unit: IW16P1 Interworking Unit 16 x E1/T1/J1


Sixteen physical TDM electrical interfaces, each with a bandwidth of: 2048 kbit/s (E1) or 1544 kbit/s (T1/JT1)


MGW for MSS (U3B)


RS232 Clock reference output to TSS3

Location: For WCDMA E1/T1/JT1 and GSM E1 or GSM T1/JT1 only: Up to three units in CAMA subrack 3 and 4, and all CAMB and CAMC subracks

Figure 14 NIWU

3.4.4 IP NIU, IP Network Interface Unit Fast / Gigabit Ethernet

The IP NIU can be either IPGE, IPGEP, IPFE, IPFEP, IPGO or IPGOP. The IP NIU (IPFE / IPGE / IPGO if not redundant, IPFEP / IPGEP / IPGOP if 2N redundant) provides Fast Ethernet (100 Mbps) and electrical and optical Gigabit Ethernet external interfaces and the means to execute physical and IP layer functionality.

Purpose: The IP NIU maps IP packets to and from Ethernet frame structure including packet classification, forwarding, scheduling and traffic management.

Redundancy: IPGE: None IPGEP: 2N IPFE: None



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IPFEP: 2N IPGO: None IPGOP: 2N

Type: IP Interface unit

Plug-in Unit: IPFGE

Interfaces: IPGE/IPGEP: 1 x 1000Base-T Ethernet IPFE/IPFEP: 8 x 100Base-TX Ethernet IPGO/IPGOP: 1 x 1000Base-LX/LH Ethernet

Location: IP NIU units can be equipped in CAMA subracks 3 and 4, and in CAMB subracks 1 and 2.

Figure 15 IP NIU (IPFGE)

3.4.5 IWS1E/T

Purpose: The IWS1E/T unit provides STM-1/VC-12 (63 PCM) and OC-3/VC-11 (84 PCM) interfaces and a direct interface to SDH/SONET transmission equipment. It implements user plane conversions of an STM-1/OC-3 user channel bit stream to an ATM user channel cell stream. It also terminates narrowband SS7 signalling links and performs narrowband / broadband conversion. The unit supports

MGW for MSS (U3B)


two ATM protocols, AAL1 and AAL5, for internal communication purposes.

Redundancy: None

Type: Network Interface unit

Plug-in Unit: IW1S1 PSTN Interworking Unit, E1/T1/JT1 over STM-1/OC-3 63 E1 (VC-12 in STM-1) or 84 T1 (VC-11 in OC-3) or 84 JT1 (VC-11 in OC-3)


Two physical STM-1/OC-3 optical interfaces, each with a bandwidth of 155,52 Mbit/s

Interfaces: ATM interface to MXU RS232 Clock reference output to TSS3

Location: For WCDMA STM-1/OC-3 one unit and for GSM STM-1/OC-3 two units in CAMA subracks 3 and 4, and all CAMB and CAMC subracks

Figure 16 STM1/OC-3 (IWS1)



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3.5 Switching and Multiplexing Units

Switching and multiplexing in the MGW is based on the Asynchronous Transfer Mode (ATM) technology with full support to the various traffic types used in the network. The units in this category are the following:

• ATM Switching Fabric Units (SFUs) which are used for switching the calls processed by the exchange

• Multiplexer Units (MXUs), for connecting the low-bit-rate network interface units, along with the computer units and signal processing units (which typically have small to moderate bandwidth requirements) to the ATM switch fabric

• AAL 2 Switching Units (A2SUs), which ensure efficient transport of information with limited transfer delay for low-to-moderate bit-rate units connected to the main switch fabric.

In addition, the units in this block provide the ATM interface which serve as the main message bus between the units in the exchange. Upper-level control functions for all three units are performed by the CACU functional unit. ATM Connections to SFU

Figure 17 ATM connections to SFU

MGW for MSS (U3B)


The SFU switching fabric has 16 ports for connections to the other units in the exchange, with an aggregate capacity of 10 Gbit/s (equivalent to 32 STM-1 lines); each port, in turn, has a capacity of 622 Mbit/s. The connections through the ports are allocated in the following manner:

• Some ports are used for the external high-bit-rate connections provided by NIS1/ NIS1P & IP-NIU

• The other ports are used for connections to the low-bit-rate network interface units and the computer units via the mutually redundant MXU pairs. One MXU pair requires one port.

The equipment of the MGW is organised as groups of units around its MXU pairs, with each group connecting to a MXU pair of its own. Normally, one such group occupies one subrack, with the exception of the equipment connecting to the first MXU pair, which requires two subracks' space (CAMA subracks 1 and 2).

3.5.1 SFU, Switching Fabric Unit

Purpose: The SFU serves as the main switch fabric of the exchange. It operates according to a non-blocking connection principle, which means that a connection can be established any time provided that the needed input and output capacity is available. The SFU supports both point-to-point and point-to-multipoint connection topologies, as well as differentiated handling of various ATM service categories.

Redundancy: 2N

Type: Switch Fabric unit

Plug-in Unit: SF10 ATM Switch Fabric Plug-in Unit 10 Gbit/s


10 Gbit/s

Interfaces: ATM interfaces: Swithc fabric interfaces for NI4S1 network interfaces Multiplexer interfaces from SFU's unit computer to OMU (via MXUs) OMU from the unit computer of the SFU (for OAM purposes and software uploads, via MXUs)

Location: One unit in each of CAMA subracks 1-2



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Figure 18 SFU

3.5.2 MXU, Multiplexer Unit

Purpose: The MXU units enable connection of the low-to-medium bit-rate signal processing units and control computers, as well as low-bit-rate network interface units, to the ATM switch fabric. The task of the MXU is to perform the multiplexing and de-multiplexing of ATM cells and perform ATM layer management and processing functions such as header translation, UPC/NPC parameter control, OAM functions, traffic management, performance monitoring and collection of performance data.

Redundancy: 2N

Type: ATM switching unit, subunit of SFU

Plug-in Unit: MX622-C / MX622-B ATM Multiplexer Plug-in Unit 622 Mbit/s


622 Mbit/s

Interfaces: ATM interfaces to: SFU switching block SFU unit computer

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control computer units network interfaces TCU and A2SU connection between the passive MXU via the active one to OMU (for OAM purposes)

Location: One unit in CAMA subrack 1 and its back-up unit in CAMA subrack 2; two mutually redundant units in all other CAMA, CAMB and CAMC subracks

Figure 19 MXU

3.5.3 A2SU, AAL 2 Switching Unit

Purpose: The A2SU is an AAL Type 2 CPS minipacket switching unit, which is used in association with the Multiplexing Unit (MXU) for facilitating connections between the main Switch Fabric SFU and the low-to-moderate bit-rate units (control computers, signal processing units and low-bit-rate network interface units). The function of the A2SU is to limit the transfer delay and ensure the general efficiency of the transportation of information in these connections by dividing the incoming ATM cells up in AAL2 Type 2 CPS minipackets and reorganising these into new ATM cells, which it sends further.



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Redundancy: SN+

Type: Switching unit, subunit of MXU

Plug-in Unit: AL2S-B / AL2S-A / AL2S AAL2 Switching Unit


Location: For all configurations except GSM STM-1/OC-3 with no units: one unit in CAMA subracks 3, 4 and one in each CAMB and CAMC subracks

Figure 20 A2SU

3.6 Timing, power distribution and HMS

The timing, power supply and hardware management subsystems form the lowest level in the computing hierarchy of the IPA2800 network elements. Each subsystem is composed of a redundant master unit and a duplicated data distribution/collection bus. In each case, the bus actually extends through some lower level units to virtually all of the exchange's plug-in units, which are

MGW for MSS (U3B)


equipped with dedicated hardware blocks supporting the core parts of the subsystem. The the network element's clock distribution and Hardware Management subsystems (TBU), use the same two types of plug-in units, namely:

• TSS3, Timing and Synchronisation, SDH Stratum 3 • TBUF, Timing Buffer.

The clock system meets Stratum 3 level accuracy requirement, as defined in Bellcore TA-NWT-1244 standard. The Power Distribution Subsystem in the exchange uses two types of plug-in units, namely:

• PD20, Power Distribution Plug-in Unit 20 A • CPD80-B /-A, Cabinet Power Distributor 80 A.

3.6.1 TBU, Timing and Hardware Management Bus Unit

The Timing and Hardware Management Bus Unit is responsible for the network element syncronisation, timing signal distribution and message transfer functions in the hardware management system. The TBU is a duplicated functional unit that consists of two plug-in units in each subrack as well as a serial bus spanning all plug-in units of the network element. The two plug-in units, the Timing and Synchronisation, SDH Stratum 3 (TSS3) and Timing Buffer (TBUF) and their functios are described below.

3.6.1.1 TSS3, Timing and Synchronisation, SDH Stratum 3

Purpose: The TSS3s generate the clock signals necessary for synchronising the functions of the MGW. Normally, the TSS3 operates in a synchronous mode, that is, it receives an input timing reference signal from an upper level of the network and adjusts its local oscillator to the long time mean value by filtering jitter and wander from the timing signal. It transmits the reference to the plug-in units in the same subrack (all plug-in units are equipped with onboard PLL blocks), as well as to the TBUF units, which distribute the signals to units not directly fed by the TSS3s. The TSS3 has inputs for both synchronisation references from other network elements (via the network interfaces) and for those from external sources (options are 2,048 kbit/s, 2048 MHz or 1.54 MHz) If all synchronisation references are lost, the TSS3 can operate in plesiochronous mode, that is, by generating independently the synchronisation reference for the units in the exchange. The TSS3s are also involved in the functioning of the HMS bus. They collect the alarms from the PIUS in the same subrack and transfer them further to the HMS master net, which brings the



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alarms to the appropriate OMU.

Redundancy: 2N

Type: Functional unit with TBUF units as sub-units

Plug-in Unit: TSS3 Timing and Synchronisation, SDH Stratum 3

Interfaces: Synchronisation reference interfaces: three line inputs (from STM-1 or TDM lines) two external inputs (2,048 kbit/s, 2048 MHz, 1.54 MHz eight outputs to cabinet timing buses one output to subrack timing bus Alarm interfaces: one input from PIUs in same subrack one output to OMU via HMS Master Net

Location: One unit in each of CAMA subracks 1-2

3.6.1.2 TBUF, Timing Buffer

Purpose: The TBUF unit is a clock buffer which distributes the synchronisation signals generated by the TSS3s to plug-in units not directly fed by the TSS3s. Like the TSS3s, the TBUFs are also involved in the functioning of the HMS bus. They collect the alarms from the PIUS in the same subrack and and transfer them further to the HMS master net, which brings the alarms to the appropriate OMU.

Redundancy: 2N

Type: Functional unit, sub-unit of the TSS3

Plug-in Unit: TBUF Timing Buffer

Interfaces: Synchronisation reference interfaces: • one input from TSS3 or another TBUF • one output to subrack timing bus • one output to another TBUF

Alarm interfaces: • one input from PIUs in same subrack • one output to OMU via HMS Master Net

Location: One unit in each of CAMA subracks 1-2; two units in all other CAMA, CAMB and CAMC subracks.

MGW for MSS (U3B)


Figure 21 TBU

3.6.1.3 Connection principle and redundancy for the timing and synchronisation distribution bus routing

The MGW has two separate timing and synchronisation distribution buses to ensure 2N redundancy for the intermal timing signal distribution. Each bus has its own system clock (a TSS3 plug-in unit), distribution cabling and timing buffers (TBUF plug-in units). The two TSS3 units backing each other up are placed in different subracks (subracks 1 and 2), each of which is powered by a power supply plug-in unit of its own to ensure redundancy for the power supply. Each of these subracks is also equipped with a TBUF plug-in unit, which connects the equipment in the subrack to the other clock distribution bus. The CAMA subracks 3 and 4 and all CAMB subracks, on the other hand, have all two separate TBUF units which connect to different clock distribution buses by means of cables of their own. The clock distribution principle in the exchange is shown in the figure below.



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51 © NOKIA MSS MGW ITG.PPT

Figure 22 Routing of the duplicated clock distribution bus

3.6.2 HMS subsystem

The hardware management subsystem has three hierarchically organised layers of equipment. The highest level in the hierarchy is formed by the Hardware Management Master Nodes (HMMNs), one in each OMU, which control the whole subsystem. The TSS3s and TBUFs in the subracks have separate Hardware Management System Bridge nodes (HMSBs), which form the next, intermediate level in the hierarchy. As the name suggests, they serve as bridges which connect HMMNs to the lowest-level blocks in the hierarchy, Hardware Management System Slave Nodes (HMSSs). Implemented as dedicated hardware blocks in all plug-in units, the latter are independent from the other blocks of the plug-in unit, for example, in terms of the power supply. A block diagram which illustrates the HMS subsystem implementation is shown in the figure below.

MGW for MSS (U3B)


Figure 23 Block diagram of the HMS subsystem

The MGW has also two mutually redundant hardware management buses, which are implemented by means of the same plug-in units as the timing and synchronisation buses, that is, the TSS3s and the TBUFs. The routing of the hardware management buses, however, differs somewhat from that of the timing and synchronisation buses. The Hardware Management Bus is organised in such a way that the TSS3s and TBUFs are on an equal level of the subsystem; both act as parallel HMS bridges which connect the plug-in units in the same subrack to the HMS master net, which brings the alarms to the appropriate OMU.



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©NOKIA MSS MGW ITG.PPT

Figure 24 Routing of the duplicated HMS bus

3.6.3 Power Distribution Subsystem

Purpose: The Power Distribution Subsystem distributes the -48V power from the rectifiers or batteries to the equipment inside the MGW cabinets. This subsystem consists of two CPD80-B/-A power distribution panels at the top of each cabinet, one PD20 power distribution plug-in unit in each subrack and the associated cabling. See the Cable Lists for a visual reperesentation of the power feed to each subrack. The PD20 unit also controls the cooling equipment of its own subrack on the basis of messages sent by the OMU.

MGW for MSS (U3B)


Redundancy: Power distribution subsystem is duplicated by providing two independent feeding input branches from cabinet level to plug-in unit level.

Type: Subsystem

Plug-in Unit: CPD80-B /-A Cabinet Power Distributor 80 A PD20 Power Distribution Plug-in Unit 20 A

Interfaces: One duplicated input from the station power supply to the CPD80; or one input for each of the two CPD80-B/-As. Four duplicated outputs to subracks (in CPD80) or four outputs to subracks (in CPD80-B) Four duplicated inputs from CPD80 (in PD20) outputs to four groups of plug-in units (in PD20) Fan tray control and alarm interface

Location: Either one CPD80 unit or two CPD80-B /-A units at the top of each cabinet; one PD20 plug-in unit in each subrack

Figure 25 Power distribution system



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3.7 EHU, External Hardware Alarm Unit

Purpose:

The purpose of External Hardware Alarm Unit is to receive external alarms and send indications of them as messages to OMU-located external alarm handler via HMS. A second function is to drive the optional External Hardware Alarm panel (EXAU), the cabinet integrated lamp, CAIND alarm indicator located on the top of CAMA cabinet and possible other external equipment.

Redundancy: None

Type: Functional Unit

Plug-in Unit: EHAT External Hardware Alarm Terminal

Interfaces:

Interfaces include 32 voltage controlled inputs, 8 current controlled inputs, 16 general purpose 20 mA current outputs. Connections to external devices via cabling panel 1 located in the rear of the CAMA cabinet.

Location: One unit per network element, in CAMA subrack 1.

3.7.1 EXAU, External hardware alarm panel

The optional peripheral EXAU provides a visual alarm of the fault indications of the MGW. The EXAU panel is located in the telecommunications site rooms, outside the network element.

3.7.2 CAIND, Cabinet alarm indicator

The CAIND is located on the top of CAMA cabinet and provides a visual alarm indicating the network element with a fault.

MGW for MSS (U3B)


4 MGW Hardware Configuration The MGW have three different equipment cabinets, namely: Cabinet Module A (CAMA) Cabinet Module B (CAMB) Cabinet Module C (CAMC) The subracks are assigned with numbers starting from 1 at the top of each cabinet and ending to 4 at its bottom. The following figure shows all the equipment cabinets and cabling cabinets in the MGW.

Figure 26 MGW cabinets and subracks

The configurations of the MGW support left-to-right or alternatively right-to-left cabinet installation as shown by the figure below. The cabinets must always be installed into a single row.

MGW Hardware Configuration


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Figure 27 Overview of U3A/B MGW configurations, new deliveries

Notes:

• CPLC36: Connector panel for STM-1 interfaces with 36 pieces of LC connectors

• CPSY: Connector panel for synchronisation with 4 pieces of BNC connectors and 6 pieces of RJ45 connectors for external synchronisation inputs and outputs.

• CPAL: Connector panel for alarms with one D25 connector for EXAU controls, one D37 connector for general current/voltage outputs, 2 pieces of D37 connectors for voltage controlled

• CPLAN-A: Connector panel for LAN interfaces (10/100 BASE-T/ TX) with 32 pieces of RJ-45 connectors

• CPETS: Connector panel for E1/T1/JT1 balanced interfaces with 32 pieces of RJ-45 connectors

• CPETC-B: Connector panel for E1 unbalanced interfaces with 64 pieces of BT43 connectors

• CPBP: Blank panel All the configurations have the CAMA, and the two first subracks in the CAMA cabinet (the base module) are the same for all configurations. All other subracks are equipped according to the configuration and capacity needed, the main difference between the configurations being the type and number of interface units. Mixed configurations are implemented by combining subracks with different configuration specific equipping within the network element.

MGW for MSS (U3B)


The minimum configuration of the MGW features only the CAMA cabinet where subracks 1-2 are fully equipped and subracks 3-4 are partially equipped. TBUF and PD20 plug-in units are always equipped to empty subracks in all three cabinets. Expanded capabilities can be obtained by:

• adding new cabinets and the necessary plug-in units in the empty subracks according to the chosen configuration, and

• connecting internal cabling for the SFU, Timing and HMS.

For expansions, the MGW provides roughly two kinds of capacities that can be increased: interface capacity and user plane processing (DSP) capacity. The processing capacity of the MGW is increased by adding TCUs, ISUs and MXUs. The interface capacity is then added independently by adding NIWU, NIP, NIS, IPNIU and IWS1E/T units. The capacity of the MGW depends on the number of PIUs installed and is expanded to 1024 speech channels with 8 TCUs for the MWG. There can be 7 units/ subrack in CAMA and 8 units / subrack in CAMB and CAMC.

The two first subracks in the CAMA cabinet (the base module) house nearly all 2N redundant equipment in the network element. Units, which make up a mutually redundant pair are placed in separate subracks. Each of the two subracks has an individual configuration, with N+1 redundant units or those with no redundancy equipped in some of the slots. The equipping of the base module is the same for all configurations.



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Figure 28 Equipment in CAMA subrack 1 (base module)

Figure 29 Equipment in CAMA subrack 2 (base module)

MGW for MSS (U3B)


66 ©NOKIA MSS MGW ITG.PPT

Figure 30 Equipment in CAMA subracks 3–4



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Figure 31 Equipment in CAMB subracks 1–4

MGW for MSS (U3B)


Figure 32 Equipment in CAMC subracks 1–4

Error! Reference source not found.


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5 Nokia MGW Interfaces 5.1 Physical connections in Nokia MGW

Since Nokia MGW can be used in both 2G and 3G environment, it provides flexible alternatives for both TDM- and packet-based interfaces. MGW provides the possibility to combine both ATM and IP interfaces in one element according to network demands. All interface types can be scaled independently, thus making it possible to have only those interfaces which are required in each element

Figure 33. Multimedia Gateway interfaces

MGW for MSS (U3B)


5.2 ATM Backbone in Nokia MGW

The Nb reference point in the 3GPP model describes the interface between two MGWs. Nokia gateway utilises several ATM adaptation layer protocols for media transport:

• AAL1 PVC/SVC for circuit-switched data and for PCM-coded speech • AAL2 for compressed speech and for non-real-time data transport

• AAL5 PVC/SVC carries user and control data and transports IP traffic

ATM forum has specified UNI 4.0 and this protocol is used for creating SVC connections from gateway to border ATM backbone element. Physical connection is STM-1 VC-3 or VC-4 confirming ITU-T G.957 S-1.1. Four STM-1 interfaces per unit are provided, and transmission medium is single mode fiber.

5.3 IP Backbone in Nokia MGW

Nokia Multimedia Gateway provides the possibility to use IP backbone networks as such for transporting media for circuit-switched connections between gateways (Nb reference point). In All-IP mobility core networks, the IP backbone is used to transport speech traffic between the GGSN and Multimedia Gateway (Gi reference point). The natural choice for transmitting media over IP in backbone connections is the IP over SDH/Sonet. Media over the IP backbone is transferred using the real time protocol (RTP). RTP provides end-to-end delivery services for data with real-time characteristics, such as interactive audio. These services include payload type identification, sequence numbering, time stamping and delivery monitoring. This makes RTP an ideal protocol for real-time applications such as voice over IP (VoIP). The network interface unit in the Nokia Multimedia Gateway provides the following options for transmitting media over IP:

Nokia MGW Interfaces


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• 1 Gigabit Ethernet interface (1000 Base-T, 1000 Base-LX; Full duplex,

auto-negotiation, flow control, MTU>1500 bytes) • 8 Fast Ethernet interfaces (100 Base-TX; Full duplex, auto-negotiation,

flow control, MTU>1500 bytes)

Figure 34. IP connectivity for user plane

5.3.1 Separating signalling from user plane

By default, both signalling (containing SIGTRAN traffic and H.248 traffic) and user traffic are routed via the IP-NIU unit using either fast ethernet (FE) or 1G interfaces. If FE interfaces are used, Multimedia Gateway provides the possibility to assign separate physical interfaces for signalling traffic and user plane traffic. This is to provide better security for the signalling against external attacks. If 1G interface is used for the user plane, then there is no possibility to isolate signalling traffic into a separate physical ethernet interface via IP-NIU. In such cases, the signalling can be routed directly from ISU units to layer 2 switches located at the Multimedia Gateway cabinet, and from those switches then to router and MSC Server or gateway control server.

MGW for MSS (U3B)


5.4 TDM Backbone in Nokia MGW

Nokia Multimedia Gateway can be easily adapted to the existing mobile environment by using the existing TDM-based transmission network also in the Nb interface. If the existing transmission network is cost-efficient, and if there are no other reasons (such as need for more capacity) for changing the transmission network type, it does not prevent the operator from taking the Rel.4 network into use. Upgrading to the Rel.4 level inevitably requires changes in the network because the control plane and user plane traffic are separated. The TDM backbone makes it possible to reduce the number of simultaneous changes when upgrading the network to the Rel.4 level. This way, the Rel.4 deployment can be divided into several easily controllable phases, thus lowering, for example, schedule risk in the network installation phase. Changing the backbone to a packet-based one for reaching all Rel.4 benefits can then be scheduled to a later phase according to operator-specific plans.

5.5 Nokia MGW control interface

The Mc reference point in the 3GPP model describes the interface between the MGCF and the Multimedia Gateway, between the MSC Server and Multimedia Gateway, and between the GMSC Server and Multimedia Gateway. It is fully compliant with the H.248 standard work carried out by the IETF MEGACO workgroup.

5.5.1 MGW control protocols (MEGACO/H.248)

MGCP and MEGACO/H.248 are protocols used between the Media Gateway Controller and the Media Gateway. The MEGACO protocol is also known as H.248 as it is being developed co-operatively between the IETF MEGACO workgroup and the ITU-T. Currently, Nokia officially supports MEGACO as defined by the ITU. The gateway supports the MEGACO protocol to perform the following tasks:

• reserve and connect terminations • connect or release echo canceller to terminations

• connect or release of tones and announcements to terminations

• send/receive DTMF tones



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5.6 Iu interface in Nokia MGW

The Iu-CS interface is used to interconnect the UMTS RAN towards the Nokia Multimedia Gateway. The interface is ATM-based, either STM-1 or TDM connections can be used (as in Multimedia Gateway Rel.99). These connections can be used to Iu_CS traffic. Also Iu_PS traffic towards packet core can be routed via the same physical medium to Multimedia Gateway and cross-connected in the Multimedia Gateway to SGSN. AAL2 is supported over Iu-CS for user plane and that traffic is routed to destination network interface (another Iu, PSTN, or ATM/IP backbone) directly from the Multimedia Gateway. AAL5 is used for control plane. This RANAP signalling is routed from the RNC to the Multimedia Gateway where it is extracted and sent to the MSC Server (typically) over Ethernet. Physical connection is STM-1 supporting VC-4 and 3 x VC-3 formats conforming ITU-T standard G.957 S-1.1. Four STM-1 interfaces per unit are provided, and transmission medium is single mode fiber. Another option is to use TDM interfaces for ATM connectivity. Up to 16 E1/T1/JT1 ATM interfaces can be used to form one ATM IMA (Inverse Multiple Access) interface over conventional PCM connections where the bandwidth requirements are low and capacity and cost optimisation is necessary.

Figure 35. Iu interface options

MGW for MSS (U3B)


5.7 A-interface in Nokia MGW

The A-interface belongs to the family of SS7 signalling system and is used for transmission of speech, data and signalling between MSC and BSS. A-interfaces are connected either to the MSC Server or to Multimedia Gateway, depending on the operator needs. If the A-interface is connected to Multimedia Gateway, then BSSAP signalling is routed to MSC Server and handled there. The physical interface used is E1/T1/JT1.

5.8 Interface towards PSTN and other TDM-based networks in Nokia MGW

Multimedia Gateway typically serves as an interconnect point between two different types of networks, providing an interconnection for both signalling and media between TDM-based and packet (or cell)-based networks. All TDM-based networks are considered identical in the Multimedia Gateway from the signalling point of view. In case a call is routed from a packet-based network towards the PSTN interface, then echo cancellers are connected from Multimedia Gateway to the speech path to prevent the electrical echo generated by the interconnection. Signalling towards other TDM networks is handled using SS7 standards. ISUP The ISDN user part (ISUP) provides facilities for handling the ISDN bearer services (including Telephony) and supplementary services for voice and data applications. The Message Transfer Part is used to carry the information of the ISUP message. MAP The mobile application part (MAP) protocol is specifically designed for non-call transactions between the GSM switching and database elements that support the roaming of mobile subscribers. TUP The telephone user part (TUP) provides facilities for handling telephone call control functions in national and international networks. The Message Transfer Part is used to carry the information of TUP messages. The physical interface towards other TDM networks is E1/T1/JT1.



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Alternatively, STM-1 VC-12 (STS-3 VC-11) is provided for environments where large interconnect points are desired. STM-1 VC-12 allows connecting of 63 E1 interfaces (or alternatively 84 T1 interfaces) over a single fiber.

MGW for MSS (U3B)


Glossary

2G 2nd Generation mobile phone network

3G 3rd Generation mobile phone network

3GPP Third Generation Partnership Project

AAL ATM Adaptation Layer

AEMF ATM Equipment Management Function

AMR Adaptive Multi-rate Speech Codec

ATM Asynchronous Transfer Mode

BSSAP Base Station Subsystem Application Part

CACU Control and Administrative Computer Unit

CAMA Cabinet Module A

CAMB Cabinet Module B

CAMC Cabinet Module C

CM Central Memory

CMISE Common Management Information Service Element

CORBA Common Object Request Brokerage Architecture

CPS Connection Processing Server

CPU Central Processing Unit

CS Circuit Switched

DSP Digital Signal Processing

EDGE Enhanced Data Rates For GSM

FTP File Transfer Protocol

GCS Gateway Control Server

GERAN GSM/EDGE Radion Access Network

GPRS General Packet Radio Service

GSM Global System For Mobile Communications

HMMN Hardware Management Master Node

HMS Hardware Management System

HMSB Hardware Management System Bridge node

HMSS Hardware Management System Slave Node

HSS Home Subscriber Server

IMA Inverse Multiplexing for ATM

Glossary


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IMSI International Mobile Subscriber Identification

IN Intelligent Network

INAP Intelligent Network Application Part

IP Internet Protocol

IP-NIU can be either IPFE/IPFEP, IPGE/IPGEP or IPGO/IPGOP

ISU Interface Control and Signalling Unit IWS1 Network Interface Unit STM-1/OC-3 M3UA

MTP3 User Adaptation MAP

Mobile Application Part MGCF

Media Gateway Control Function MGW

Multimedia Gateway MMI

Man Machine Interface MML

Man Machine Language MSC

Mobile Switching Centre MSS

MSC Server MSSu

Upgraded MSC Server MTP

Message Transfer Part NEMU

Network Element Management Unit NIP1 Network Interface Unit PDH NIS1

Network Interface Unit STM-1 NIWU

Network Interface Unit TDM NPC

Network Parameter Control ( used in NNI) OAM

Operations, Administrations and Maintenance O&M

Operation & Maintenance OMU

Operational And Maintenance Unit PDH

Plesiochronous Digital Hierarchy PLMN

Public Land Mobile Network PSTN

Public Switched Telephone Network PVC

Permanent Virtual Connection RAN

Radio Access Network RANAP

Radio Access Network Application Part

MGW for MSS (U3B)


RNC Radio Network Controller

RTP Real Time Protocol

SCCP Signalling Connection Part

SCSI Small Computer Systems Interface

SCTP Stream Control Transmission Protocol

SDH Synchronous Digital Hierarchy

SIGTRAN Signalling Transport

SIP Session Initiated Protocol

SPMU Signal Processing Management Unit

SS7 Signalling System # 7

SVC Switched Virtual Connection

TBU Timing and Hardware Management Bus Unit TBUF Timing Buffer TMSI

Temporary Mobile Subscriber Information T-SGW

Transport Signalling Gateway TSS3 Timing and Synchronisation, SDH Stratum 3 UE

User Equipment UMTS

Universal Mobile Telecommunication System UPC

Usage Parameter Control ( used in UNI ) USB

Universal Serial Bus UTRAN

UMTS Terrestrial Radio Access Network VANU Voice Announcement Unit VC-3/ VC-4/ VC12 Virtual Container , structural part of an STM-1 frame consisting of path

overhead and a container VMSS

Visited MSC Server

Documents

03 MGW for MSSread.pudn.com/downloads207/doc/975609/material_from_nokia/03_MGW for MSS.pdfOptional upgrades in U3A and U3B are the new WCDMA STM-1/OC-3 and GSM STM-1/OC-3 configuration