WO1991009366A1 - Procede et appareil de commande de la circulation entre des entites terminales reparties dans des reseaux informatiques - Google Patents

Procede et appareil de commande de la circulation entre des entites terminales reparties dans des reseaux informatiques Download PDF

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Publication number
WO1991009366A1
WO1991009366A1 PCT/US1990/007377 US9007377W WO9109366A1 WO 1991009366 A1 WO1991009366 A1 WO 1991009366A1 US 9007377 W US9007377 W US 9007377W WO 9109366 A1 WO9109366 A1 WO 9109366A1
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WIPO (PCT)
Prior art keywords
entity
data
station
receiving
transmitting
Prior art date
Application number
PCT/US1990/007377
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English (en)
Inventor
Roger W. Flynn
Larry P. Lipke
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E-Systems, Incorporated
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 E-Systems, Incorporated filed Critical E-Systems, Incorporated
Publication of WO1991009366A1 publication Critical patent/WO1991009366A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/10—Flow control; Congestion control
    • H04L47/30—Flow control; Congestion control in combination with information about buffer occupancy at either end or at transit nodes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/10—Flow control; Congestion control
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/10—Flow control; Congestion control
    • H04L47/26—Flow control; Congestion control using explicit feedback to the source, e.g. choke packets
    • H04L47/266—Stopping or restarting the source, e.g. X-on or X-off
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L69/00—Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F11/00—Error detection; Error correction; Monitoring
    • G06F11/07—Responding to the occurrence of a fault, e.g. fault tolerance
    • G06F11/14—Error detection or correction of the data by redundancy in operation
    • G06F11/1402—Saving, restoring, recovering or retrying
    • G06F11/1415—Saving, restoring, recovering or retrying at system level
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F11/00—Error detection; Error correction; Monitoring
    • G06F11/07—Responding to the occurrence of a fault, e.g. fault tolerance
    • G06F11/16—Error detection or correction of the data by redundancy in hardware
    • G06F11/20—Error detection or correction of the data by redundancy in hardware using active fault-masking, e.g. by switching out faulty elements or by switching in spare elements

Definitions

  • the present invention relates to a method and apparatus for controlling the flow of data among a plurality of computing devices. More particularly it relates to a protocol for allowing an end-entity in a network computer to be placed in and removed from a temporary condition of flow control that is recognizable in real time by the other end-entities in the computer network.
  • An end-entity is the tasks or processes within a station which perform the information processing for a particular system in a local area network (LAN) computer environment.
  • LAN local area network
  • Computer networks providing data communication channels between communicating end-entities in interconnected systems rely primarily on embedded software for protocols and services to support a reliable mode of behavior. Examples are: the TCP-IP and X.25 protocols used by the Department of Defense and the emerging International Standards Organization's (ISO) Open System Interconnection (OSI) Model targeted for new applications.
  • ISO International Standards Organization's
  • OSI Open System Interconnection
  • connection establishment In conventional LANs a connection is required to be established prior to reliable communications in an OSI environment.
  • the connection has three distinct phases: (a) connection establishment;
  • a connection is the controlling mechanism set forth to provide not only reliable communications, but flow control between peer end-entities as well.
  • every end-entity pair desiring to communicate must first establish a connection.
  • resources at all routers are set aside during each individual connection setup.
  • the number of simultaneous connections allowed, in any application is therefore a function of the resources available throughout the LAN.
  • the number of simultaneous connections required in many applications can quickly become prohibitive.
  • management of the limited connection resources is difficult, time-consuming, and is usually an additional requirement for end-entities.
  • LANs employing a partial connection of hardware offer an improvement over the conventional systems.
  • the Prioritized Carrier Sense Multiple Access with Collision Detect (P-CSMA/CD) with Tack-on Acknowledgement (T-ACK) access method and apparatus described in U.S. Patent Nos. 4,536,877 and 4,584,679 includes a reliable datagram mechanism between stations in a LAN implemented primarily in hardware.
  • a reliable datagram service as employed here is defined as a perfect channel: one that has no lost or duplicated data messages as a result of the transmission media, and one in which data messages sent from the transmitting entity, through the transmission media to the receiving entity, arrive in the order sent.
  • the P-CSMA/CD with T-ACK access method also provides station level flow control as a function of message priority and of the number of buffers currently available at the receiving station. It provides two levels of filtering: filtering based on destination address, and filtering based on priority of input data frame versus number of remaining receive buffers to handle the incoming frame.
  • the filtering by priority may be viewed as station level flow control.
  • the P-CSMA/DC with T-ACK mechanism provides a hardware connection-like or virtual circuit service between stations, it does not provide a mechanism to prevent one or more end-entities from monopolizing the resources available at that station; that is, there is a station-to-station level of flow control in the P- CSMA/CD with T-ACK protocol, but no entity-to-entity level of flow control.
  • Some LANs provide end-entity flow control in a higher level of software protocol as a means to equitably share the end system resources among end users.
  • the mechanism used in these LANs relies on a broadcast control message transmitted to every sending station in the network to convey any state change for any destination end-entity in any end system.
  • flow control tables in this protocol are global in nature, requiring the protocol entity component that is resident in every end system to track the current state of every end- entity in every other end system, regardless of the intention to ever send to that entity;
  • congestion is managed by a central controller (see, for example, U.S. Patent No. 4,677,616 to Franklin dated June 30, 1987) or by node controllers (see U.S. Patent No. 4,475,192 to Fernow, et al. dated October 2, 1984). These devices require additional hardware and do not substantially reduce the flow control management overhead.
  • Figure 1 is a functional block diagram of a prior art computer network in which the present invention may be used.
  • FIG. 2 is a functional block diagram of the transmitting station acknowledgment handler of the present invention.
  • FIG. 3 is a functional block diagram of the receiving station acknowledgment generator of the present invention.
  • the present invention provides flow control between communicating end-entities in a computer network.
  • a preferred embodiment of the invention utilizes an architecture based on the International Standards Organization (ISO) Open Systems
  • Application Serves as window between correspondent end- entities using OSI. Constitutes the sole interface between end station applications and the LAN. Presentation — Concerned with syntax or representation of data (may include services such as encryption) . Session — Controls a dialogue established between communicating end-entities (concerned with data checkpoint/restart problem, dialogue recovery, or change of turn) . Transport — Provides end-to-end transfer of data messages between communicating entities in open systems (message packetization and flow control) . Network — Controls routing of message packets to end systems worldwide. Datalink — Controls routing of message packets between stations. This layer is further subdivided into the Logical Link Control (LLC) and Media Access Control (MAC) sublayers.
  • LLC Logical Link Control
  • MAC Media Access Control
  • CSMA/CD Carrier Sense Multiple Access with Collision Detect
  • MAC Media Access Control
  • the IEEE 802.3 standard is actually a family of specifications.
  • the particular member of the 802.3 standard used in this embodiment is the 10BASE5 subset. This subset specifies that the transmission speed is 10 Mbits/sec, that the keying method is baseband (DC levels) , that the medium used is Ethernet coaxial cable, that the maximum cable length without repeaters is 500 meters, and that the maximum number of end stations allowed without repeaters is 100. Only one cable can be used.
  • SUBSTITUTESHEET Messages to be transmitted under 10BASE5 are presented to the MAC sublayer from the Logical Link Control (LLC) sublayer of the Datalink layer.
  • the MAC sublayer encapsulates the message data (LLC Data) with header and trailer information, forming a MAC frame. Frames sent by this access method are made up of a number of octets which are transmitted serially on the medium.
  • Each MAC frame contains the following information:
  • Preamble 7 octets of a fixed bit pattern (10101010) which allows receiving stations to synchronize with the incoming frame's timing.
  • Start Frame Delimiter SFD
  • Destination Address 6 octets specifying the physical address of the destination (receiving) end station.
  • Source Address 6 octets specifying the physical address of the source (transmitting) end station.
  • Length 2 octets specifying the length of the frame.
  • LLC Data Up to 1500 octets of data. Note that this data may include header information used in higher layers of the protocol.
  • Frame Check Sequence FCS
  • FCS Frame Check Sequence
  • CRC Redundancy Check
  • a station waits (defers) for a quiet period on the medium (no other station is transmitting) and then sends the intended message in bit serial form.
  • the transmitting station continues to monitor the physical medium for interference from other sending stations while transmitting. If transmission is completed without contention, then a successful status is returned to the LLC sublayer. The only error status returned from this MAC service is maximum collisions (currently set to 16 in 10BASE5) .
  • the arrival of a MAC frame causes the receiving hardware to respond by synchronizing with the incoming preamble. After receipt of the FCS, the frame's Destination Address field is checked to decide whether the frame is to be received by this station. If so, the rest of the fields are brought in and the frame is checked for correctness.
  • a frame is incorrect if it is too short, too long, not an integer number of octets, or if it contains an incorrect CRC in the FCS field. Tw or more stations transmitting simultaneously (a collision) will also result in the creation of an incorrect frame, known as a frame fragment.
  • Valid LLC Data fields are presented to the Logical Link Control sublayer of the Datalink layer for reading and further processing in the destination end-entity.
  • the MAC sublayer continually monitors the physical medium for traffic. Whenever the medium is busy, the MAC sublayer defers to the passing frame by delaying any pending transmission of its own. After the medium goes idle, the MAC sublayer continues to defer for a proper Interframe Spacing (9.6 microseconds in 10BASE5) to ensure that effects of medium propagation delay and hardware delays at receiving stations are factored into the medium idle (Carrier Sense) decision. Then, if a frame is ready to be sent, transmission begins.
  • Interframe Spacing 9.6 microseconds in 10BASE5
  • each transmitting station intentionally sends a few additional bytes (jamming) to ensure propagation of the collision throughout the system.
  • the station then remains silent for a random amount of time (backoff) before attempting to transmit again. It is possible for repeated collisions to occur in a heavily loaded system. Since repeated collisions indicate a busy medium, the MAC sublayer attempts to adjust to the medium load by expanding the interval from which the random backoff time is selected.
  • the present invention contains an enhanced Carrier Sense Multiple Access/Collision Detection (CSMA/CD) protocol designed around the 10BASE5 CSMA/CD media access method specified in IEEE 802.3.
  • the enhancements are:
  • T-ACK TACK-ON Acknowledgment
  • the hardware generated T-ACK (see aforementioned U.S. Patent Nos. 4,536,877 and 4,584,679) contains status information sent by the receiving station back to the sending station at the completion of the transmitted frame. This feature is implemented by making use of a portion of the interframe gap (thereby extending it) to transmit the acknowledgement. Since no other station is allowed to transmit during this period, collisions should not occur. Since only the sending station is expecting the acknowledgment, destination and source address fields are not required and the size of the frame can be quite small.
  • the T-ACK consists of:
  • Preamble and SFD Identical in structure to the Preamble and SFD in the MAC frame previously defined; Status — a one-octet status field currently containing only three bits of significant information (8 states) ; and FCS - a two-octet FCS using the CRC-CCITT international standard generator polynomial.
  • the other enhancement is the addition of fields to the MAC frame for end-entity flow control.
  • the MAC frame to be transmitted in the present invention is identical to the 802.3 MAC frame with three additional extra fields incorporated. These additional fields are: Sequence number — a single-octet field containing the sequence number for the transmitted frame. Used in maintaining in-sequence frames in a multimedium environment.
  • Priority a single-octet field containing the message priority of the transmitted frame.
  • Logical Address A two-octet field uniquely identifying the destination end-entity of the transaction in the receiving station.
  • the additional MAC frame header fields and the status contained in the T-ACK frame provide the following services:
  • Priority A priority mechanism indicating a quality of service expected to be provided by the underlying protocol, for each message sent.
  • the MAC sublayer in conjunction with upper layer protocol, provides end-entity flow control at the media level.
  • Message reliability is ensured at the media level, by the addition of the T-ACK and the sequence number field. Message reliability means that there are no lost or duplicated messages and that a stream of messages sent between any two stations will remain in the original order of transmission. Fast sending stations are prevented from overrunning slower receiving stations.
  • the T-ACK contains status information informing the sending station as to the success or failure of each transmission. If the receiving station rejects the incoming frame, for any reason, it conveys this information back to the sender via the T-ACK. The sending station then responds by resending the frame.
  • a level of determinism is added to the transmission access method by the establishment of priority levels on a message-by- message basis. Eight priority levels are available for use; seven are available to sending end-entities, and one is reserved for internal network management services. The priority of a
  • SUBSTIT T particular message may be established by the user of the sending end-entity and passed in the Datalink layer.
  • the MAC sublayer adjusts the value of the 9.6 microsecond interframe gap timer by lengthening it in increments of 9.6 microseconds per priority level. So a message to be sent at priority level seven will be deferred for a much longer period than a higher priority message before beginning a transmission. Transmitting stations initiate a final carrier sense operation prior to transmitting (look before leap) and defer if a higher priority frame has already acquired the cable.
  • the total number of receive buffers available for receipt of frames is distributed on a priority basis.
  • the receiving station hardware either accepts or rejects the incoming frame based on the number of remaining buffers in the receive buffer pool. Higher priority messages are allocated a larger share of the overall receive buffer pool. If a receiving station rejects an incoming frame for lack of buffers at that frame's priority level or below, then the receiving station will indicate this to the sender by returning a "NO BUFFERS" status in the T- ACK status field. The sender will then defer before sending messages at that priority level, or lower, allowing the receiving station to work off the load.
  • End-entity flow control is made possible by the addition of the T-ACK, and the logical address field in the MAC frame.
  • the MAC sublayer derives the value to be placed in the logical address field of the MAC header from the service access point address of the destination end- entity.
  • This derivation algorithm uses maps and compresses the overall address of the destination end-entity into an address in the destination end system. Mapping is from an address unique within the entire LAN into an address unique only within the destination end system.
  • the MAC sublayer maintains the current state of each of its embedded end-entities. There are three possible states for these end-entities to be in: detached (or nonexistent) , attached and ready to receive, or attached and in flow control. As a station is powered up, every end-entity address is mapped into the detached state in the MAC sublayer hardware. As end-entities are activated, the MAC sublayer is commanded to activate them at the media level. As end-entities enter and exit flow control, the MAC sublayer hardware is updated by commands from upper level protocol to reflect the current state.
  • the receiving station accepts or rejects an incoming MAC frame based on the current state of the locally resident end- entity pointed to by the logical address field in the frame. In either case, the sending station is notified via the T-ACK. In the case of a rejection, the sending station defers from sending to that destination entity until: (a) normal exit (notification by broadcast from the receiving station that end-entity flow control is removed) , or (b) time-out retry (end of time-out countdown started at the time the frame was enqueued) . The sending station also notifies upper layer protocol to allow back pressure to be applied to the local users, thereby avoiding congestion in the local BIU.
  • the apparatus of the present invention may use multiple media, such as a dual cable configuration.
  • a selection process such as a round-robin scheme may be employed to that end.
  • End-entities that communicate on the LAN contain a component of the Application layer built in at link time. There are basically two classes of services:
  • the network management services allow end-entities to attach (announce themselves to the network) , detach (remove themselves f * om the network) , and perform directory lookups of other end- entities for purposes of communicating.
  • An end-entity must be attached prior to sending or receiving data communications. This provides an access point to the LAN and gives other end-entities the opportunity to look up and communicate with this newly attached end-entity.
  • the communication services provide end- entities with the basic sending and receiving capabilities.
  • the upper layer protocol in the end station using the underlying MAC sublayer flow control services, provide the flow control between each receiving end-entity and all other transmitting end-entities.
  • the portion of the protocol related to data transmission is in the sending host, and the portion of the protocol related to data reception is in the receiving host.
  • This database contains a set of parameters used to tune the network.
  • This parameter set includes a minimum and maximum threshold for the number of receive buffers waiting for . an end-entity.
  • the parameters are set by the LAN manager based on the total number of buffers in the local receive buffer pool (a parameter in the database) and the maximum number of expected end-entities to be simultaneously attached to the network (also a parameter) .
  • the current number of messages in the entity's queue is compared against the upper level threshold in the receiving host. If this threshold is crossed, the receiving host sends a control primitive to the MAC sublayer, placing this end-entity into flow control. No further data communications for this end-entity are allowed to enter this end station. As the end-entity removes data elements from the queue (via a component of the Application layer resident in the end-entity's task space) the lower threshold is checked against the current queue size. When the lower threshold is crossed, the MAC sublayer is commanded to remove the end-entity from flow control. This built-in hysteresis is designed to prevent thrashing.
  • SUBSTITUTESHEET A computer network in which the present invention may be used is illustrated in Figure 1 wherein a plurality of transmission media 10 are connected to a plurality of bus interface units 20 such as in a local area or metropolitan area network.
  • the transmission media may be any suitable electronic transmission media including such media as twisted pair wire, high speed busses, fiber optic cables, coaxial cable, or radio frequency (RF) carrier waves.
  • RF radio frequency
  • Each of the bus interface units 20 interconnects an end station 22 to the plurality of transmission media 10.
  • the end station 22 can be any conventional computer or computer-based device, such a work station, printer, or memory unit.
  • Messages are generated at one of the end stations 22 and relayed through the associated bus interface unit 20 for forwarding to a second end station 22 through its associated bus interface unit 20.
  • the message is propagated along one of the plurality of transmission media 10 and is available for receipt by any of the bus interface units 20 connected to the transmission medium 10 along which the message is propagating.
  • the receiving bus interface unit 20 buffers and relays the message from the transmission medium 10 to the end station 22.
  • Each end station includes one or more end-entities which process the information in the message or perform specific tasks.
  • An end system 15 includes a bus interface unit 20 and its corresponding end station 22 with associated end-entities.
  • the present invention may be divided into two portions: the transmitting station acknowledgment handler, and the receiving station acknowledgment generator.
  • the transmitting station acknowledgment handler is further divided into two portions: the transmitting bus interface unit (BIU) acknowledgment handler 120 (hereafter referred to as the sending BIU) , and the transmitting end station acknowledgment handler 122 (the sending host) .
  • BIU transmitting bus interface unit
  • the receiving station acknowledgment generator is further divided into two portions: the receiving bus interface unit (BIU) acknowledgment handler 140 (hereafter referred to as the receiving BIU) , and the receiving end station acknowledgment handler 142 (the receiving host) .
  • BIU receiving bus interface unit
  • the receiving end station acknowledgment handler 142 the receiving host
  • the sending BIU 120 places a receiving end-entity 150 unique identifier in a control area of the sending data frame received from a transmitting end-entity 130. After sending the data frame, the sending BIU 120 receives the short hardware generated acknowledgment from the receiving end station 42 containing status information. As previously described, the present invention adds three new hardware states that the receiving end- entity 150 can be in, and therefore adds three new values of status to report back to the sending BIU 120 in the acknowledgment generated by acknowledgment reporter 45 in BIU 40. These new states are: (a) Entity Detached, (b) Entity Attached and Currently Receiving Data Frames, (c) Entity Attached and Currently in Flow Control.
  • the sending BIU 120 Upon receiving in acknowledgment receiver 25 an Entity Flow Control status (state (c) above) in the hardware generated acknowledgment, the sending BIU 120 informs its sending host 122 that the receiving end-entity is in a flow control status.
  • the sending host 122 exerts back pressure on the end station 22 by deferring future attempts at sending data communications to this receiving end-entity 150.
  • This back pressure is applied to all locally resident end-entities 130 that attempt to send to the receiving end-entity 150 in flow control status and may be manifested in several ways. For example, (1) operation of end- entities 130 attempting to transmit to an end-entity 150 in flow control may be suspended until flow control is exited, or (2) attempted transmission may be returned to the end-entity 13 in error status.
  • the choice may be made by the user of the transmitting end-entity 130 when end-entity parameters are established. Transmissions of end-entities 130 attempting to send to an end-entity 150 in a Detached status (state (a) above) are returned in error status.
  • the sending BIU 120 enqueues messages rejected by the receiving end station 42 due to Entity Flow Control status until one of two events occur: (a) Normal Exit, or (b) Time-out Retry.
  • the receiving BIU 140 parses the incoming data frame, extracting the receiving end-entity 150 identifier from the frame and accepting or rejecting the frame based on the current flow control state for that end-entity. This decision is made by the receiving BIU 140 so that the decision to accept or reject may be conveyed back to the sending station in the acknowledgment generated in acknowledgment reporter 45.
  • the receiving host 142 monitors the state of the receiving end-entities 150 in its receiving station 42 that are currently attached to and using the services of the LAN. Receiving end- entities 150 are placed in flow control and removed from flow control based on a measurement of the receiving end-entity's current congestion. The number of data messages in the end- entity's input queue may be used as such a measure of congestion.
  • FIGS 2 and 3 depict the transmitting and receiving components as separate entities, it is understood that each end system on the computer network may contain both components.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Computer Security & Cryptography (AREA)
  • Communication Control (AREA)

Abstract

Dans un système de réseau informatique, un procédé et un appareil permettent de placer une entité terminale (150) situé dans un ordinateur du réseau dans un état temporaire de commande de la circulation reconnaissable en temps réel par d'autres entités terminales (130) du réseau informatique, et de la faire quitter ledit état. Une station de réception (22) évalue et dresse un rapport sur les communications qui attendent d'être traitées par une entité terminale incorporée (150). Le rapport indique si l'entité terminale réceptrice (150) est (a) déconnectée, (b) disponible ou (c) dans un état de commande de la circulation. Si l'entité terminale réceptrice (150) est en état de commande de la circulation, la station émettrice met les communications adressées à l'entité terminale (150) dans sa propre queue (120) d'attente pour transmission ultérieure, déclenchée par la réception d'un message de changement d'état émis par l'entité terminale (150) ou par l'écoulement d'une période déterminée. La station émettrice (22) vérifie si les communications de données ont été transmises avec succès par le milieu de transmission (10) et dans la négative, lorsque l'entité terminale réceptrice (150) est en état de commande de la circulation, arrête des transmissions futures à cette entité terminale (150) jusqu'à la cessation de l'état de commande de la circulation. La station réceptrice (42) accepte ou rejette le message entrant selon l'état actuel de commande de la circulation de lentité terminale destinataire (150). Les entités terminales sont placées en état de commande de la circulation ou quittent cet état en fonction d'une mesure de l'encombrement actuel de l'entité terminale réceptrice (150).
PCT/US1990/007377 1989-12-19 1990-12-17 Procede et appareil de commande de la circulation entre des entites terminales reparties dans des reseaux informatiques WO1991009366A1 (fr)

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US452,429 1989-12-19

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EP0561381A3 (en) * 1992-03-18 1995-09-20 Fischer & Porter Co Network architecture suitable for multicasting and resource locking
WO1998037668A1 (fr) * 1997-02-25 1998-08-27 Telefonaktiebolaget Lm Ericsson (Publ) Reseau de communication multi-acces a gestion dynamique des acces
US6078568A (en) * 1997-02-25 2000-06-20 Telefonaktiebolaget Lm Ericsson Multiple access communication network with dynamic access control
EP1361696A1 (fr) * 2002-05-09 2003-11-12 Altima Communications, Inc. Ajustement dynamique d'un seuil d'abandon pour le traitement équitable des trames de données unicast et multicast
US7286547B2 (en) 2002-05-09 2007-10-23 Broadcom Corporation Dynamic adjust multicast drop threshold to provide fair handling between multicast and unicast frames
US7764704B2 (en) 2002-05-09 2010-07-27 Broadcom Corporation Dynamic adjust multicast drop threshold to provide fair handling between multicast and unicast frames
EP1730899A1 (fr) * 2004-01-30 2006-12-13 Telefonaktiebolaget LM Ericsson (publ) Distribution de paquets pour transmission continue de donnees

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