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    21.
    发明专利
    未知

    公开(公告)号：DE69327692D1

    公开(公告)日：2000-03-02

    申请号：DE69327692

    申请日：1993-08-24

    Applicant: IBM

    Inventor： AHMADI HAMID ,  GUERIN ROCH A ,  DERBY JEFFREY HASKELL ,  GUN LEVENT ,  MARIN GERALD ARNOLD ,  NAGHSHINEH MAMOUD ,  SOHRABY KHOSROW

    IPC: H04L29/06 ,  H04L12/56

    Abstract: A congestion control system for packet communications networks in which access to the network is controlled to prevent such congestion. Packets within the pre-specified statistical description of each packet source are marked as high priority ("green" packets) while packets exceeding the pre-specified characteristics are marked with a lower priority ("red" packets). The overall red packet rate is limited to prevent red packet saturation of the network. The introduction of red packets into the network is subjected to a degree of hysteresis to provide better interaction with higher layer error recovery protocols. The amount of hysteresis introduced into the red packet marking can be fixed or varied, depending on the statistics of the incoming data packets at the entry point to the network.

    Adaptive Medium Access Control Scheme for Wireless LAN
    22.
    发明专利
    Adaptive Medium Access Control Scheme for Wireless LAN 未知

    公开(公告)号：CA2115211A1

    公开(公告)日：1994-10-20

    申请号：CA2115211

    申请日：1994-02-08

    Applicant: IBM

    Inventor： AHMADI HAMID ,  BANTZ DAVID F ,  BAUCHOT FREDERIC ,  KRISHNA ARVIND ,  LAMAIRE RICHARD O ,  NATARAJAN KADATHUR S

    IPC: H04J3/00 ,  H04B7/24 ,  H04J3/16 ,  H04L12/28 ,  H04L12/56

    Abstract: A Medium Access (MAC) Protocol is utilized for wireless radio access for a plurality of remote stations to a base station on a LAN. The MAC protocol is based on a reservation scheme for user data traffic and a random access technique for control and signalling traffic. There is a time division fixed frame structure in which time is slotted, and time slots are grouped into fixed frames consisting of data and control subframes or periods. The fixed frame structure consists of three periods (A, B, and C) along with their respective headers. The first period, the A period, is the outbound channel which is used exclusively for data transfer from the base station to the remote stations. The following period, the B period, is the inbound channel that is used for contention-free data transfer from the remote stations to the base station. The allocation of the data slots in the A and B periods is performed by the base station. The last period of the frame, designated as the C period, is the control channel used for the transmission of reservation requests and data from the remote stations to the base station in a random-access contention mode using a slotted Aloha protocol. The duration of the three periods may be varied using a movable boundary technique. The base station estimates the number of actively transmitting remote stations utilizing feedback information from the remote stations. This estimate is broadcast to the remote stations as control indicia to control their transmission attempts in the C period, thus yielding high transmission efficiency.

    23.
    发明专利
    未知

    公开(公告)号：DE3788649D1

    公开(公告)日：1994-02-10

    申请号：DE3788649

    申请日：1987-10-20

    Applicant: IBM

    Inventor： AHMADI HAMID ,  BEHA JOHANNES GEORG ,  DENZEL WOLFGANG ,  ENGBERSEN ANTONIUS ,  LUIJTEN RONALD ,  MURPHY CHARLES ,  PORT ERICH

    IPC: H04L12/56 ,  H04L12/54 ,  H04L12/58

    Abstract: In a switching system interconnecting transmission links (21-i, 23-i) on which circuit switched (CS) and packet switched (PS) information is transferred, a switch fabric (11) is provided which interconnects a plurality of input ports (15-i) to a plurality of output ports (19-i). The information arriving on incoming links is converted in switch adapters (13-i) to uniform minipackets, each having a routing address designating the required output port. The switch fabric consists of parallel equal switching slices, e.g. binary routing trees (71), which transfer in a non-blocking manner each minipacket from its input port to one output port in response to the routing address. Collecting means (73, 75) are provided at each output port for accepting the minipackets arriving from the different input ports.

    26.
    发明专利
    未知

    公开(公告)号：AT199617T

    公开(公告)日：2001-03-15

    申请号：AT94105696

    申请日：1994-04-13

    Applicant: IBM

    Inventor： AHMADI HAMID ,  BANTZ DAVID FREDERICK ,  BAUCHOT FREDERIC JACQUES ,  KRISHNA ARVIND ,  LA MAIRE RICHARD ORVILLE ,  NATARAJAN KADATHUR S

    IPC: H04J3/00 ,  H04B7/24 ,  H04J3/16 ,  H04L12/28 ,  H04L12/56 ,  H04B7/204

    Abstract: A Medium Access (MAC) Protocol is utilized for wireless radio access for a plurality of remote stations to a base station on a LAN. The MAC protocol is based on a reservation scheme for user data traffic and a random access technique for control and signalling traffic. There is a time division fixed frame structure in which time is slotted, and time slots are grouped into fixed frames consisting of data and control subframes or periods. The fixed frame structure consists of three periods (A, B, and C) along with their respective headers. The first period, the A period, is the outbound channel which is used exclusively for data transfer from the base station to the remote stations. The following period, the B period, is the inbound channel that is used for contention-free data transfer from the remote stations to the base station. The allocation of the data slots in the A and B periods is performed by the base station. The last period of the frame, designated as the C period, is the control channel used for the transmission of reservation requests and data from the remote stations to the base station in a random-access contention mode using a slotted Aloha protocol. The duration of the three periods may be varied using a movable boundary technique. The base station estimates the number of actively transmitting remote stations utilizing feedback information from the remote stations. This estimate is broadcast to the remote stations as control indicia to control their transmission attempts in the C period, thus yielding high transmission efficiency.

    TRAFFIC MANAGEMENT IN PACKET COMMUNICATIONS NETWORKS
    29.
    发明专利
    TRAFFIC MANAGEMENT IN PACKET COMMUNICATIONS NETWORKS 未知

    公开(公告)号：CA2099031C

    公开(公告)日：1999-01-19

    申请号：CA2099031

    申请日：1993-06-23

    Applicant: IBM

    Inventor： AHMADI HAMID ,  GUERIN ROCH ,  GUN LEVENT

    IPC: H04L12/56 ,  H04L12/26 ,  H04Q1/24

    Abstract: In a packet communications network, the addition or deletion of a connection to the network by a user is governed by a link traffic metric which represents the effective capacity of each link in the network which participates in the packet connection route. The link metric is calculated in real-time and updated by simple vector addition or subtraction. Moreover, this link metric is also used to calculate leaky bucket parameters which govern the access of packet s to the network once the connection is set up. A packet network using these link metrics and metric generation techniques provides maximum packet throughput while, at the same time, preserving grade of service guarantees.

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