WO1996038959A1 - Reseau et procede de mise en oeuvre d'un groupe de travail - Google Patents

Reseau et procede de mise en oeuvre d'un groupe de travail Download PDF

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Publication number
WO1996038959A1
WO1996038959A1 PCT/EP1996/002339 EP9602339W WO9638959A1 WO 1996038959 A1 WO1996038959 A1 WO 1996038959A1 EP 9602339 W EP9602339 W EP 9602339W WO 9638959 A1 WO9638959 A1 WO 9638959A1
Authority
WO
WIPO (PCT)
Prior art keywords
network
port
switch
workgroup
ports
Prior art date
Application number
PCT/EP1996/002339
Other languages
English (en)
Inventor
Tadhg Creedon
Anne O'connell
Eugene O'neill
Vincent Gavin
Ciaran Murphy
John Hickey
Original Assignee
3Com Ireland
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 3Com Ireland filed Critical 3Com Ireland
Priority to GB9725273A priority Critical patent/GB2316281A/en
Priority to AU75138/96A priority patent/AU7513896A/en
Publication of WO1996038959A1 publication Critical patent/WO1996038959A1/fr

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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
    • H04L49/00—Packet switching elements
    • H04L49/35—Switches specially adapted for specific applications
    • H04L49/351—Switches specially adapted for specific applications for local area network [LAN], e.g. Ethernet switches

Definitions

  • the present invention relates to computer networks and more particularly networks which are usually known as local area networks (LANs).
  • LANs local area networks
  • Local area networks are now well known and can vary in size considerably. With a network of anything more than a few ports, it is customary to separate the network into operational areas so that those devices which will normally wish to share information and/or send information to each other are grouped together but are able to communicate with other portions of the network via a device known variously as a bridge or switch.
  • a bridge or switch One of the features of a bridge or switch is that it contains an up-to-date list of all device addresses and the ports to which those devices are connected.
  • the network is separated not only notionally by the bridges and switches and even by routers but also physically into a plurality of separate housings which are interconnected in order to form the network. Even with this degree of physical separation of parts of the network, it is not possible to efficiently handle all the traffic which may occur with large networks particularly when multicasts or broadcasts are being transmitted.
  • the present invention provides a method whereby each port in a switch or bridge is provided with an additional identifier whereby ports may be grouped together, to create a separable network.
  • the grouping of the ports is in fact achieved by adding additional addressing bits to a packet, which additional addressing bits are indicative of the work group of the source port.
  • the destination port logic checks its own additional addressing bits against the additional addressing bits in the packet and if there is a disparity at that stage it ignores the packet.
  • the additional addressing bits be added by the port logic as the packets enter a switch or bridge so that the extra addressing bits do not appear on the network and thus the packets as seen by the network conform with the normal network standard.
  • Fig. 1 shows diagrammatically a computer network inco orating a number of bridges or structures
  • Fig. 2 shows one embodiment of a bridge or switch used in the network shown in Fig. 1;
  • a local area network will be separated up into a number of discrete areas using bridges or switches and that the ports incorporated within one or more areas will be provided as ports on a box which is also provided with its own microprocessor and CAM.
  • Fig. 1 where a network is shown as being formed by a main network 1 to which is attached bridges or switches 2 and 3.
  • Each switch supports a number of devices attached to ports of the switch in a conventional manner. It is common to supply multi-port bridges or switches with a predetermined number of ports but problems arise when a user wishes to connect more devices to a bridge than there are ports available. In the past this has required replacing the multi-port bridge with another having a greater number of ports or adding another complete bridge.
  • a bridge or switch be assembled from one or more identical modules and for the sake of this example we will use four identical modules ABCD as shown in Fig. 2 which when connected together will function as a single bridge or switch as far as the network is concerned.
  • Each module is provided with a number of ports to which devices can be connected.
  • Fig. 2 we show that there are ten ports numbered 0-9 for each module for this purpose although it will be noted that port 0 of module A is in fact the port which connects to the rest of the network.
  • Each module is also provided with an additional port 10 which is used as a communications port with access to a local bus 11 so that data can be transferred from module to module.
  • an additional port 10 can be provided for a bridge or switch simply by supplying one or more modules and connecting them to the data bus 11.
  • the microprocessor and CAM of each module knows the relationship between all ports and the MAC addresses of all devices attached thereto for its own module.
  • each module has built up a table of port and device addresses in the normal fashion.
  • each entry in the table indicative of the device MAC address and its associated port will also contain additional addressing information which will be used to associate ports with each other even though they may be separated from each other by a bridge or switch.
  • the amount of additional addressing required is a function of the number of work groups. For the purposes of this example we will assume that the additional addressing is in the form of a four bit word. A four bit word will allow up to 16 work groups. Other sizes of word from a single bit to a much larger word could also be used depending on the user's requirements.
  • the microprocessor inspects the destination address in the packet for additional addressing information in the form of a four bit word which is indicative of the work group of the source port. Packets with no known destination address for that box can be switched based on the additional addressing information to one of a number of down links no matter where they are on the stack.
  • additional addressing bits indicating the work group of a port allows ports to be grouped together functionally but each group of ports to be separable from each other although all ports will be on the same bridge or switch. It also allows devices connected to ports of one bridge or switch to be functionally associated with devices or another bridge or switch. Each work group on a switch is provided with its own port for communicating with the rest of the network and in this way virtual networks can be created.
  • the communications port need not be port 0 as shown in the drawings. This is shown in Fig. 1 where the switch or bridge 2 has only one down link to the rest of the network whereas switch 3 has two down links one from module A and one from module D indicating two work groups present in switch 3. In this example, since a four bit word is being used as additional addressing it will be appreciated that up to 16 down links would be present from just one switch.
  • Fig. 1 Asynchronous Transfer Mode (ATM) network.
  • ATM Asynchronous Transfer Mode
  • the main network 1 in Fig. 1 could be either an ethernet network or an ATM network.
  • An ATM network takes a packet and breaks it up into smaller blocks each with its own header. The blocks are then sent down a single down link together with blocks from the parts of the network in a multiplexed fashion.
  • Work groups can also be used to improve the security of unicast traffic and there is no need to construct a switch or bridge from a number of modules.
  • the general principles outlined apply to all bridges and switches.

Landscapes

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

Abstract

Chaque port d'un commutateur ou d'un pont est pourvu d'un identificateur additionnel, les ports pouvant être regroupés les uns avec les autres pour créer un réseau virtuel séparé. Chaque port émetteur ajoute des bits d'adressage supplémentaires à un paquet dont les bits d'adressage indiquent le groupe de travail du port émetteur. Cette opération s'effectue de préférence lorsque les paquets entrent dans un commutateur ou dans un pont. Chaque port destinataire comporte une logique qui vérifie ses propres bits additionnels par rapport aux bits additionnels du paquet. En cas de disparité à ce stade, le port destinataire concerné ignore ledit paquet. Ce système permet d'améliorer considérablement l'efficacité du traitement des données.
PCT/EP1996/002339 1995-05-31 1996-05-30 Reseau et procede de mise en oeuvre d'un groupe de travail WO1996038959A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB9725273A GB2316281A (en) 1995-05-31 1996-05-30 Network and method for implementing a workgroup
AU75138/96A AU7513896A (en) 1995-05-31 1996-05-30 Network and method for implementing a workgroup

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9510933.6 1995-05-31
GB9510933A GB9510933D0 (en) 1995-05-31 1995-05-31 Simple work group implementation mechanism

Publications (1)

Publication Number Publication Date
WO1996038959A1 true WO1996038959A1 (fr) 1996-12-05

Family

ID=10775244

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP1996/002339 WO1996038959A1 (fr) 1995-05-31 1996-05-30 Reseau et procede de mise en oeuvre d'un groupe de travail

Country Status (3)

Country Link
AU (1) AU7513896A (fr)
GB (2) GB9510933D0 (fr)
WO (1) WO1996038959A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999029072A1 (fr) * 1997-11-28 1999-06-10 3Com Technologies Troncs communs dispositifs de communication empiles
WO2000072533A1 (fr) * 1999-05-21 2000-11-30 Broadcom Corporation Configuration d'empilement pour commutateurs de reseau
US6236654B1 (en) 1997-02-14 2001-05-22 Advanced Micro Devices, Inc. Method and apparatus for managing learning in an address table in memory
US6813268B1 (en) 1999-05-21 2004-11-02 Broadcom Corporation Stacked network switch configuration
US7581038B1 (en) 2006-03-16 2009-08-25 Polycom, Inc. Multicast distribution over one or more addressable buses wherein a switch includes a remapping table for inputting address for one or more destinations
US7715328B2 (en) 1999-12-07 2010-05-11 Broadcom Corporation Mirroring in a stacked network switch configuration

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
"VIRTUAL LANs GET REAL", DATA COMMUNICATIONS, vol. 24, no. 3, 1 March 1995 (1995-03-01), pages 87 - 92,94,96,98,100, XP000496027 *
MANDEVILLE R: "ETHERNET SWITCHES EVALUATED HANDS-ON TESTING SHOWS THAT SOME VENDORS' GEAR CAN HIT FULL WIRE SPEED ON EVERY PORT WITHOUT DROPPING PACKETS - AND NO NEW ADAPTERS OR CABLING ARE REQUIRED", DATA COMMUNICATIONS, vol. 23, no. 4, 1 March 1994 (1994-03-01), pages 66 - 70, 72, 74, 76, 78, XP000432076 *

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6236654B1 (en) 1997-02-14 2001-05-22 Advanced Micro Devices, Inc. Method and apparatus for managing learning in an address table in memory
US6269098B1 (en) 1997-02-14 2001-07-31 Advanced Micro Devices, Inc. Method and apparatus for scaling number of virtual lans in a switch using an indexing scheme
US6356551B1 (en) 1997-02-14 2002-03-12 Advanced Micro Devices, Inc. Method and network switch having dual forwarding models with a virtual lan overlay
WO1999029072A1 (fr) * 1997-11-28 1999-06-10 3Com Technologies Troncs communs dispositifs de communication empiles
GB2346524A (en) * 1997-11-28 2000-08-09 3Com Technologies Ltd Trunking in stacked communication devices
GB2346524B (en) * 1997-11-28 2002-10-02 3Com Technologies Ltd Trunking in stacked communication devices
WO2000072533A1 (fr) * 1999-05-21 2000-11-30 Broadcom Corporation Configuration d'empilement pour commutateurs de reseau
US6813268B1 (en) 1999-05-21 2004-11-02 Broadcom Corporation Stacked network switch configuration
US7593403B2 (en) 1999-05-21 2009-09-22 Broadcom Corporation Stacked network switch configuration
US7715328B2 (en) 1999-12-07 2010-05-11 Broadcom Corporation Mirroring in a stacked network switch configuration
US7581038B1 (en) 2006-03-16 2009-08-25 Polycom, Inc. Multicast distribution over one or more addressable buses wherein a switch includes a remapping table for inputting address for one or more destinations

Also Published As

Publication number Publication date
GB2316281A (en) 1998-02-18
GB9725273D0 (en) 1998-01-28
AU7513896A (en) 1996-12-18
GB9510933D0 (en) 1995-07-26

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