DHS3 Release 1 System General Description


Chapter 1 Scope


A new range of Alcatel PABXs will cover the market from 50 to 8000 users. This range is called DHS3x. This range is covered by several system configurations called DHS 30, 32 and 34 depending on the capacity of the system.

The whole DHS 3x program is split in two parts: one called release 0 which includes the DHS 30/32 configuration the other called release 1 which includes the DHS 34 configuration .This document describes the architecture and the services of the DHS 30 / 32 systems which will cover the range between 50 and 800 users.

Sometimes in this document we use the name DHS3 which is the generic name for DHS 30 and DHS 32.


Chapter 2 Terms and definitions


2.1. Standard acronyms and abbreviations


802.3 IEEE standard for CSMA/CD access method.

802.5 IEEE standard for Token ring access method.

802.6 IEEE standard for MAN ( metropolitan area network) access method.

ACSE The Application Control Service Element is an ASE that provides basic facilities for the control of an application-association between two applications entities that communicate by means of a presentation-connection.

AGENT PROCESS Agent processes perform the management function upon receipt of directives specifying management operations on managed objects.

API Application Programming Interface. Set of primitives allowing an external application to access the basic mechanisms of DHS3.

ASE  Application Service Element is a coherent set of services used for communication at the application layer level.

ASN.1 The Abstract Syntax Notation one is a language for specifying protocol message formats.

CCR The Commitment of Concurrence and Recovery is an ASE that supports atomic actions by providing concurrence controls for commitment systems and recovery procedures.

CMIP Common Management Information Protocol specifies a protocol which is used by application layer entities to exchange management informations.

CMISE  Common Management Information Service Element is an ASE which may be used by an application process in a management environment to exchange information and commands for the purpose of system management.

CSTA Computer Supported Telecommunications Applications is a standard which enhances the capabilities of both computing and switching networks.

CLNP ConnectionLess Network Protocol.

CLNS ConnectionLess Network Service.

CONS Connection Oriented Network Service.

CSMA/CD Carrier Sense Multiple Access with Collision Detect.

DCE Data Circuit terminating Equipment comprises such equipment as a modem. In an X25 context the network access and packet switching modem is classed as DCE.

DTE Data Terminal Equipment comprises user devices such as terminals and computers. The DTE connects to the DCE which interfaces to the network and handles the transmission and reception fo data.

DISA Direct In System Access; feature which allows a public subscriber to access

PABX services after having dialled a personal code

ETI Extended Terminal Interface is an UNIX library allowing the screen management of ASCII terminals.

FDDI Fiber Distributed Data Interface. Standard specifying a packet switched LAN to LAN backbone that conveys data at high throughput rates over a variety of multimode fibers.

FTAM File Transfer, Access and Management is an ASE which may be used by an application process for file transfer.

FTP File Transfer Protocol.FTP uses TCP services to control the exchange of files between two hosts. FTP consists of both a server portion and a client portion. ASCII and binary file transfers are supported. FTP also supports third party transfers where a user establishes a FTP session on a local host to transfer a file between two remote hosts.

I430/I431 Identical to S0/S2.

I441/I451 Identical to Q921/Q931.

IP Internet Protocol. The Internet Protocol is designed for use in interconnected systems of packet-switched computer communication networks.The internet protocol provides for transmitting blocks of data called datagrams from sources to destinations, where sources and destinations are hosts identified by fixed length addresses. The internet protocol also provides for fragmentation and reassembly of long datagrams, if necessary, for transmission through "small packet" networks.

IPNS ISDN PBX Networking Specification is an ISDN based protocol allowing telephonic features in network configuration.

ISDN Integrated Services Data Network.

Kermit Protocol which offers a remote terminal service and a file transfer facility. It is packet oriented and uses 8 data bits per byte and supports sliding windows and data compression.

KD This is the ETSI terminology for the digital accesses to the public switched network. KD1 represents the basic access , KD2 the primary rate access and KD3 the non ISDN digital access ( e. g. PCM 30) LAN Local Area Network. Any physical network technology that operates at high speed over short distances.

LAPB Link Access Procedure Balanced. Protocol of the X25 layer 2, based on

HDLC frame exchange.

LAPD Link Access Protocol on D channel. See Q921.

LAT Local Area Transport. LAT means DIGITAL's communications model for resource sharing between computer hosts connected to an Ethernet network and interactive and application terminals and printers connected to the same network.

LD This is the ETSI terminology for the local digital accesses to the PABX network. LD1 represents the basic access ( S0) , LD2 the primary rate access ( S2) and LD3 the non ISDN digital access ( e. g. UA )

LLC Logical Link Control. (IEEE 802.2). Data link sub-layer used in LAN communication protocols.

LME The Layer Management Entity provides the layer specific management functions.

MAO Maintenance administration and operations

MAC Medium Access Control. Data link sub-layer used in LAN communication protocols.

MANAGING PROCESS Managing Processes have the responsibility for management activities, therefore managing processes issue operations and receive notifications.

MAP Manufacturing Automation Protocol. Developed by General Motors, MAP architecture is based on OSI model. MAP products use the token bus.

MAU Medium Access Unit.

MD This is the ETSI terminology for the private links between the PABXs ( e.g. a leased line) . MD1 represents a private 2B+D link , MD2 represents a 30B+D private link and MD3 a proprietary digital private link.

MIB Management Information Base is the conceptual repository of management information within an open system.

NUMERIS Name of the French public ISDN.

PAD Packet Assembler/ Desassembler (X3 CCITT Recommandation). Term used with packet networks that refers to a terminal multiplexor device that forms a connection between terminals and hosts. A PAD accepts characters from conventional terminal and sends them across a packet network. It accepts packets from a packet network, extracts characters, and displays them on a terminal.

PAV "Point d'Accès Videotex". Identical to a PAD with extensions for videotex terminals.

PDU Protocol Data Unit. Data units specified in a protocol(N) and consisting in protocol(N) control information (PCI) and user (N) data.

PSN Private Switched Network.

Q921 Protocol of the ISDN layer 2, based on HDLC frame exchange.

Q931 Protocol of the ISDN layer 3 (network), providing the user/network interface.

QOS Quality Of Service. Set of negotiated parameters between the two cooperating entities. QOS is negotiated at connection establishment phase.

RFC Requests For Comments (RFC) provide informations, definitions and specifications of protocols used in the ARPA world (ex: TCP, IP, NFS, TELNET, SNMP ...).

ROSE The Remote Operation Service Element is an ASE that provides services to support interactive applications in a distributed open systems environment.

RTC "Reseau Telephonique Commuté". French Public Switched Network.

S0/S2 Basic and primary ISDN interfaces.

SAP Service Access Point. Point where the services(N) are provided by an entity(N) to an entity(N+1).

SMAE System Management Application Entity is the application layer entity responsible for communication between systems management application processes.

SMAP The System Management Application Process is the local process within a system that is responsible for executing system management functions.

SMASE The System Management Application Service Element defines the semantics and abstract syntaxes of information transferred as relevant to specific functional area.

SMF The System Management Functions are those functions that accomplish users requirements in an OSI management environment.

SMFA The Specific Management Functional Area is a user requirements category of systems management.

SMI The Structure of Management Information defines the logical structure of system management information.

SNA System Network Architecture. It's the IBM master plan for communications with and among IBM computers, terminals, and office systems.

SRT self routing tag; basic address allowing the automatic routing of the VLF

TCP Transmission Control Protocol. TCP is a connection-oriented, end-to-end reliable protocol designed to fit into a layered hierarchy of protocols which support multi-network applications. The TCP provides for reliable inter-process communication between pairs of processes in host computers attached to distinct but interconnected computer communication networks.

Telnet Terminal Network. Telnet builds on TCP services a fairly general bi-directional, eight-bit byte oriented communications facility. Its primary goal is to allow a user at one site to interact with a remote system at another as if the user's terminal connected directly to the remote machine.

TOP Technical and Office Protocol. Developed by Boeing, TOP architecture is based on OSI Reference model. TOP products use the CSMA/CD or Token Ring access methods.

TRANSFIX Name of a French data transmission service. It provides digital, permanent and synchronous specialized links.

TRANSPAC Name of the French public packet switched data network.

UDP User Datagram Protocol. This protocol provides a procedure for application programs to send messages to other programs with a minimum of protocol mechanism. The protocol is transaction oriented, and delivery and duplicate protection are not guaranteed.

V21/V22/V23 Set of CCITT recommendations specifying asynchronous and synchronous

V24/V35 interchange circuit definitions.

V25/V25BIS PSN automatic answering and calling equipment.

V110 Specifies the rate adaptation for the support of synchronous and asynchronous equipment using the V series type interface on a PSN.

V120 Specifies the rate adaptation for the support of synchronous and asynchronous equipment using the V series type interface on a PSN.

VLF variable length frame

WAN Wide Area Network. A network typically over relatively large geographic areas.

X3 Packet Assembly/Disassembly facility in a data network. It lists options and defaults for interactive asynchronous terminal connection to packet networks.

X11 see X-Windows.

X21 Specifies interface between DTE (Data Terminal Equipment) and DCE (Data Circuit terminating Equipment) for synchronous operations on data networks.

X31 t.b.c.

X25 Network communication packet switched protocol of the data link and network levels (connection oriented) of the OSI Reference Model.

X28 DTE/DCE interface for asynchronous DTE accessing the PAD facility.

X29/X29M Procedure for exchange of control information and user data between a packet mode DTE and a PAD facility.

X32 Procedure for access between users and packet networks thru the switched telephone network and thru circuit switched public data networks.

X500 Directory Services. Network communication protocol enabling transparent access to services in a distributed environment.

X-Windows Protocol which defines a high level interface to drive graphic terminals.


2.2. DHS3 acronyms and abbreviations


DHS3 generic name of DHS 30 and 32. It is also the name of the project which is in charge of developing the system

DHS3x generic name of the new range of Alcatel PABXs. It includes the DHS 30, 32 and 34 configurations

CLUSTER set of several interconnected crystals

CRYSTAL name of the full meshed aarchitecture


Chapter 3 Main requirements for DHS 30-32


Chapter 4 Description of the characteristics of the product


Chapter 5 Architecture of the system: the choices


Chapter 6 Architecture of the system: the  system in release 0


Chapter 7 Architecture of the system: the hardware


            7.3. CPU

Two boards are needed to implement the hardware. The CPU1 supports the processing unit while the IO1 supports the IO controller, the system clocks and power.

A connecting PCB (ATB) is plugged in front of the CPU1 and IO1 boards and conveys the power supply for the plateform, the AT bus, power station alarm and controller's watchdog signals.

Behind the back panel, a connecting board (Ccard) is plugged into the DIN sockets of IO1 and CPU1. It supports sockets for tape recorder, alarm relay logic, trunk line diversion logic, protection key, floppy disk and RS232C links (the 4 connected to the CPU).

7.3.1. CPU1 (processing unit)

7.3.2. IO1

7.4. PRA coupler

7.5. PCM coupler

7.6. UA coupler

7.7. Analog subscriber cupler

7.8. BRA coupler

7.9. INT1 couplers

            7.10. Analog specific couplers

            7.11. the USC-VG board

            7.12. US shelf

            7.13. Crystal backpanel

            7.14. Power supply architecture

            7.15. Clock and synchronisation


Chapter 8 Architecture of the system: the packaging


Chapter 9 Architecture of the system: the software