EP0543957A1 - Commutation sans connexions pour un interrupteur atm - Google Patents

Commutation sans connexions pour un interrupteur atm

Info

Publication number
EP0543957A1
EP0543957A1 EP19920906666 EP92906666A EP0543957A1 EP 0543957 A1 EP0543957 A1 EP 0543957A1 EP 19920906666 EP19920906666 EP 19920906666 EP 92906666 A EP92906666 A EP 92906666A EP 0543957 A1 EP0543957 A1 EP 0543957A1
Authority
EP
European Patent Office
Prior art keywords
field
connectionless
dqdb
switch
cell
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP19920906666
Other languages
German (de)
English (en)
Inventor
Adam Christopher Perry
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
GPT Ltd
Plessey Telecommunications Ltd
Original Assignee
GPT Ltd
Plessey Telecommunications Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by GPT Ltd, Plessey Telecommunications Ltd filed Critical GPT Ltd
Publication of EP0543957A1 publication Critical patent/EP0543957A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/54—Store-and-forward switching systems 
    • H04L12/56—Packet switching systems
    • H04L12/5601—Transfer mode dependent, e.g. ATM
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/2852—Metropolitan area networks
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/54—Store-and-forward switching systems 
    • H04L12/56—Packet switching systems
    • H04L12/5601—Transfer mode dependent, e.g. ATM
    • H04L2012/5638—Services, e.g. multimedia, GOS, QOS
    • H04L2012/5645—Connectionless
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/54—Store-and-forward switching systems 
    • H04L12/56—Packet switching systems
    • H04L12/5601—Transfer mode dependent, e.g. ATM
    • H04L2012/5638—Services, e.g. multimedia, GOS, QOS
    • H04L2012/5646—Cell characteristics, e.g. loss, delay, jitter, sequence integrity
    • H04L2012/565—Sequence integrity
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/54—Store-and-forward switching systems 
    • H04L12/56—Packet switching systems
    • H04L12/5601—Transfer mode dependent, e.g. ATM
    • H04L2012/5638—Services, e.g. multimedia, GOS, QOS
    • H04L2012/5646—Cell characteristics, e.g. loss, delay, jitter, sequence integrity
    • H04L2012/5652—Cell construction, e.g. including header, packetisation, depacketisation, assembly, reassembly
    • H04L2012/5653—Cell construction, e.g. including header, packetisation, depacketisation, assembly, reassembly using the ATM adaptation layer [AAL]
    • H04L2012/5656—Cell construction, e.g. including header, packetisation, depacketisation, assembly, reassembly using the ATM adaptation layer [AAL] using the AAL2

Definitions

  • a node has to send a message through a packet switched network which 1s of a length greater than the maximum packet size, the message is divided Into smaller packets which are sent Individually through the network.
  • the stream of packets through the network There are two approaches to sending the stream of packets through the network:- the datagram or connectionless service the virtual circuit or connection oriented service.
  • connection oriented service In the connection oriented service a pre-planned route 1s established before any packets are sent. Consequently, all packets will arrive in the order In which they were sent.
  • connectionless service The advantages of connectionless service are that call set-up time 1s avoided which is an advantage for short transactions, network congestion can be by-passed Improving performance and network failures can be by-passed improving reliability.
  • the Distributed Queue Dual Bus (DQDB) protocol specifies a hybrid network capable of carrying connectionless data as well as connection oriented and isochronous data.
  • the standard for this protocol is specified by the IEEE 802.6 Committee. However, the standardisation activity has been concentrated on defining the connectionless part of the standard and as a result, the definition of the remaining service types has been delayed.
  • connectionless data carrying DQDB slot is shown in Figure 1 and is identical to the proposed format of the ATM cell for the Type 4 ATM Adaption Layer (AAL-4).
  • AAL-4 format was originally intended to meet the needs of a connectionless, variable bit rate service class of traffic but has been enhanced to provide facilities for assured/unassured delivery and streaming mode traffic and may also be used in a connection oriented environment. Consequently there will be no special format problems generated by the interworking of DQDB and ATM at the payload level.
  • the Segment type (Seg T) field identifies.the segment as the Beginning of Message (BOM), a Continuation of Message (COM), the End of Message (EOM) segment or as a Single Segment Message (SSM);
  • the Sequence Number (SeqN) field contains a modulo 16 sequence of numbers which should be consecutive for each of the segments in a message;
  • the SeqN field will be used at the receiver to detect lost or misinserted (which includes duplicated) segments
  • MID Message Identifier
  • the value of the MID field is therefore unique for each sequence of segments comprising a message on a DQDB network. Similarly, in the case of an ATM network, the MID is also unique;
  • the Payload Length (PL) field contains a number which is a multiple of 4 in the range 4 to 44. This allows the segment contents to contain multiples of 32 bits for ease of processing;
  • CRC Cyclic Redundancy Check
  • a DQDB based Metropolitan Area Network requires that the DQDB sub-networks (dual busses) are interconnected to form an extended DQDB network which will form the core of the MAN. There are two ways in which this may be achieved:-
  • connectionless broadband service could be transparently mapped on to the connection oriented ATM layer. This approach may lead to inefficiency in the use of virtual channels due to the need to reserve connections or at least have semi-permanent Virtual Circuit Identifiers (VCIs) between connectionless users.
  • VCIs Virtual Circuit Identifiers
  • the second approach is to use a connectionless 'server' function In the broadband network. All connectionless information could be sent to this 'server' and it would cope with the forwarding of these connectionless messages to their destinations. This approach would also require some reserved VCI space, or a call set-up overhead, to be associated with each connectionless transfer.
  • a third option not included in the draft CCITT recommendation is the subject of the present invention.
  • a method of transmitting variable length messages on a telecommunications network from a source to a destination via an ATM or DQDB switch in fixed length cells or slots which include a header field and a payload field wherein the method includes providing a segment type field, a sequence number field and a message identifier field in the payload field and wherein the routing information is obtained without use of the Virtual Path or Circuit Identifiers.
  • the method obtains the routing information from the connectionless messages destination address field which may conform to the E.164 numbering plan recommended by the CCITT for the ISDN era.
  • connectionless cell switch would preferably be cheap to implement and operate. It should also be compatible with, or upgradeable to, a future connection oriented ATM/DQDB switch for ease of interworking of connectionless and connection oriented cell based information.
  • a suitable Connectionless Cell Switch would typically contain a 16 x 16 switching element comprising a pair of back-to-back switch devices such as are described in co-pending U.K. Patent Applications Nos.8917530.1 and 9019340.0 which are incorporated herein by reference thereto.
  • Switches perform cell routing by the use of "routing digits" or tags which are appended to the cell, which digits designate from which port the cell is to be sent out. These routing digits will be associated with the MID field of the connectionless or ATM cell DQDB slot.
  • the MID field itself is associated with the destination address information, possibly conforming to CCITT Recommendation E.164 included in the connectionless Protocol Data Unit (PDU). This address information is contained in the first slot containing the first segment of the PDU. The same is true for AAL-4 PDUs which can also be used to send connectionless information.
  • PDU connectionless Protocol Data Unit
  • Rate adaption will be required to convert the rate of the incoming connection to that of the switch and the management processor as it is expected that the switch will operate asynchronously of its ports and connection of dissimilar line rates will be possible.
  • the E.164 address will be used to index a small data base of known port/E.164 mappings.
  • the Connectionless Cell Switch has Its initial application, in switching connectionless traffic contained in DQDB connectionless Queue Arbitrated (QA) slots. It would, however, be able to handle Isochronous Pre-Arbitrated (PA) and Connection Oriented (QA) DQDB slots as well.
  • An ATM based connectionless service could then be provided by simply changing the Line Termination Card and using a reserved, or a small set of reserved, VCI values which could be groomed out by the front end of the connection-oriented switch and passed to the CCS.
  • the operation of the switch for the DQDB connectionless service would be the same as for a B-ISDN connectionless service therefore the term 'cell' is used below to mean either a DQDB slot or an ATM cell.
  • An incoming cell could be, identified as connectionless by its reserved VPI/VCI value. If the cell was Identified as a SSM or a BOM cell, the address (E.164) and MID values would be passed to a Management Processor. The Management Processor would then use a look-up database to discover which switch port is associated with the address (E.164) and appending a tag to the cell for use by a Header Translation Unit and Switch Management Unit. This function is broadly similar to the server functionality required in the second of the B-ISDN proposals for implementing a connectionless service. Any subsequent cells received with a MID value corresponding to the MID value associated with the address (E.164) and assigned tag values would automatically have the tag appended and be sent Into the switch unit and directed to the relevant switch port.
  • CCS DQDB Isochronous and Connection oriented service operations are specific to the use of the CCS in a DQDB environment and would be switched on their VCI/VCP values alone. This would entail a connection oriented type of management being Implemented alongside the connectionless management described above. However, this would also be the case for any DQDB Multiport Bridge which supports these services as well as the basic DQDB connectionless service.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Data Exchanges In Wide-Area Networks (AREA)

Abstract

Dans un système de télécommunications où un noeud doit envoyer par un réseau à commutation par paquets un message dont la longueur dépasse la longueur maximale prévue pour les paquets, on divise le message en des paquets plus petits, qui sont envoyés individuellement par le réseau. Les paquets peuvent être envoyés par le service dit sans connexions, où chaque paquet est traité indépendamment. L'invention propose l'envoi de paquets par une méthode de transmission de messages de longueur variables sur un réseau de télécommunications depuis une source à une destination par l'intermédiaire d'un interrupteur ATM ou DQDB (bus double à file d'attente distribuée) dans des cellules ou des créneaux à longueur fixe qui comprennent un champ d'en-tête et un champ de texte, la méthode consistant à prévoir un champ de type segment, un champ de numéro de série, et un champ d'identification de messages dans le champ de texte. Les informations de cheminement sont obtenues sans l'utilisation d'identificateurs de chemin virtuel ou de circuit.
EP19920906666 1991-03-22 1992-03-23 Commutation sans connexions pour un interrupteur atm Withdrawn EP0543957A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9106111A GB9106111D0 (en) 1991-03-22 1991-03-22 Connectionless switching for an atm switch
GB9106111 1991-03-22

Publications (1)

Publication Number Publication Date
EP0543957A1 true EP0543957A1 (fr) 1993-06-02

Family

ID=10692027

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19920906666 Withdrawn EP0543957A1 (fr) 1991-03-22 1992-03-23 Commutation sans connexions pour un interrupteur atm

Country Status (5)

Country Link
EP (1) EP0543957A1 (fr)
JP (1) JPH05507605A (fr)
AU (1) AU1562992A (fr)
GB (2) GB9106111D0 (fr)
WO (1) WO1992017014A1 (fr)

Families Citing this family (18)

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Publication number Priority date Publication date Assignee Title
US5509126A (en) * 1993-03-16 1996-04-16 Apple Computer, Inc. Method and apparatus for a dynamic, multi-speed bus architecture having a scalable interface
JP3044983B2 (ja) * 1993-08-25 2000-05-22 株式会社日立製作所 Ａｔｍスイッチングシステムのセル制御方法
JP2848784B2 (ja) * 1994-08-02 1999-01-20 沖電気工業株式会社 パケット交換方式
EP0700229B1 (fr) * 1994-08-22 2006-06-28 Fujitsu Limited Système de communication sans connection, méthode de test et système de gestion intra-station
US5923657A (en) * 1994-08-23 1999-07-13 Hitachi, Ltd. ATM switching system and cell control method
EP0719065A1 (fr) * 1994-12-20 1996-06-26 International Business Machines Corporation Noeud de communication de paquets polycalent pour un réseau de communication de données
JP2995496B2 (ja) * 1995-06-19 1999-12-27 インターナシヨナル・ビジネス・マシーンズ・コーポレーシヨン 単方向ブロードキャスト・システムにおいてデータ・パケットを受信するための方法及びシステム
JPH0974419A (ja) * 1995-09-06 1997-03-18 Fujitsu Ltd 複数データユニットを用いてメッセージを伝送する通信システムにおける同時発生メッセージ制御方式
JPH10190733A (ja) 1996-12-25 1998-07-21 Hitachi Ltd Ｉｐスイッチ、該ｉｐスイッチに用いるインターフェース回路及びａｔｍスイッチ、及びｉｐスイッチネットワークシステム
GB2320396B (en) * 1996-11-29 1998-11-11 Northern Telecom Ltd Scaleable data network router
GB2321568A (en) * 1997-01-22 1998-07-29 Northern Telecom Ltd ATM communications system and method
US6721271B1 (en) 1999-02-04 2004-04-13 Nortel Networks Limited Rate-controlled multi-class high-capacity packet switch
DE19907019A1 (de) * 1999-02-19 2000-08-24 Bosch Gmbh Robert Verfahren zur verbindungsorientierten Übertragung von Datenpaketen
US6882799B1 (en) 2000-09-28 2005-04-19 Nortel Networks Limited Multi-grained network
US7965729B2 (en) * 2001-05-23 2011-06-21 Polytechnic University Transferring data such as files
US7672639B2 (en) * 2003-01-29 2010-03-02 Globalstar, Inc. Method and system for routing telemetry in a simplex mode
JP4499489B2 (ja) * 2004-06-18 2010-07-07 株式会社エヌ・ティ・ティ・ドコモ 送信装置、受信装置、通信システム及び通信方法
GB2418565B (en) * 2004-08-18 2006-09-20 Wecomm Ltd Transmitting data over a network

Family Cites Families (1)

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Publication number Priority date Publication date Assignee Title
US4975906A (en) * 1988-02-15 1990-12-04 Hitachi, Ltd. Network system

Non-Patent Citations (1)

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Title
See references of WO9217014A1 *

Also Published As

Publication number Publication date
AU1562992A (en) 1992-10-21
JPH05507605A (ja) 1993-10-28
GB9206253D0 (en) 1992-05-06
GB2254529A (en) 1992-10-07
GB9106111D0 (en) 1991-05-08
WO1992017014A1 (fr) 1992-10-01

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