公开(公告)号：PL321754A1

公开(公告)日：1997-12-22

申请号：PL32175496

申请日：1996-01-16

Applicant: IBM

Inventor： AHMADI HAMID ,  BAUCHOT FREDERIC JACQUES ,  BONNET ROSELYNE ,  KESSLER ILAN ,  KRISHNA ARVIND ,  LANNE FABIEN P ,  NAGHSHINEH MAHMOUD ,  SOLER CATHERINE ,  WETTERWALD MICHELLE MARIE

IPC: H04B7/26 ,  G06F13/00 ,  H04L12/56 ,  H04L29/06 ,  H04L29/12 ,  H04W8/26 ,  H04W40/24 ,  H04W40/26 ,  H04W40/36 ,  H04W80/04 ,  H04W92/02 ,  H04Q7/24

Abstract: A communications network having a number of routers, a number of base stations and a number of mobile units maintains communications with the mobile units by assigning a unique address known to the routing entities of the network to each mobile unit. By including the mobile units unique address in topology updates of the network, the location of the mobile unit at any time is made known to all routers of the network. That is, once a mobile unit moves into a domain of a new access point and establishes a new link with the new access point, it uses the topology update mechanism of the network to make its new location known to all routers. Once a router of the network receives topology update information specific to the mobile unit's new location, it updates its routing table such that packets destined to the mobile unit are routed in a path which terminates at the mobile unit and contains its new access point.

公开(公告)号：CA2089789C

公开(公告)日：1997-01-21

申请号：CA2089789

申请日：1993-02-18

Applicant: IBM

Inventor： AHMADI HAMID ,  CHEN JEANE SHU-CHUN ,  CHOW CHEE-SENG ,  GUERIN ROCH ,  GUN LEVENT ,  LEE ANTHONY MANGCHUEN ,  TEDIJANTO THEODORE E

IPC: G06F13/00 ,  H04L12/56 ,  H04Q3/42

Abstract: A packet communications system utilizes a route determining mechanism by identifying principal paths between the source and the destination in the system. Principal paths are minimum hop count paths with a transmission delay less than a specified threshold. Principal path links are accepted as legs of the optimum path, if feasible, i.e., if the resulting load on the link is less than a specified principal threshold. Secondary links are accepted only if the resulting load on the link is less than a specified secondary threshold, where the secondary threshold is less than the principal threshold. All paths must also have a transmission delay less than a specified threshold. Each request for a route includes the source node, the destination node, the load required, the maximum transmission delay and, if desired, the quality of service parameters which all of the legs of the route must satisfy. A modified Bellman-Ford breadth-first searchalgorithm is used to identify the principal links and, using these principal link identifications, determining the optimum path.

公开(公告)号：CA2170786A1

公开(公告)日：1996-09-07

申请号：CA2170786

申请日：1996-03-01

Applicant: IBM

Inventor： AHMADI HAMID ,  BAUCHOT FREDERIC JACQUES ,  BONNET ROSELYNE ,  KESSLER ILAN ,  KRISHNA ARVIND ,  LANNE FABIEN P ,  NAGHSHINEH MAHMOUD ,  SOLER CATHERINE ,  WETTERWALD MICHELLE MARIE

IPC: G06F13/00 ,  H04B7/26 ,  H04L12/56 ,  H04L29/06 ,  H04L29/12 ,  H04W8/26 ,  H04W40/24 ,  H04W40/26 ,  H04W40/36 ,  H04W80/04 ,  H04W92/02 ,  H04L12/46

Abstract: A communications network having a number of routers, a number of base statio ns and a number of mobile units maintains communications with the mobile units by assigning a unique address known to the routing entities of the network to e ach mobile unit. By including the mobile units unique address in topology update s of the network, the location of the mobile unit at any time is made known to all ro uters of the network. That is, once a mobile unit moves into a domain of a new access point and establishes a new link with the new access point, it uses the topology u pdate mechanism of the network to make its new location known to all routers. Once a router of the network receives topology update information specific to the m obile unit's new location, it updates its routing table such that packets destined to the mobile unit are routed in a path which terminates at the mobile unit and con tains its new access point.

公开(公告)号：CA2137484A1

公开(公告)日：1995-06-09

申请号：CA2137484

申请日：1994-12-07

Applicant: IBM

Inventor： AHMADI HAMID ,  BANTZ DAVID ,  BAUCHOT FREDERIC ,  NATARAJAN KADATHUR ,  WETTERWALD MICHELE M

IPC: H04L12/28 ,  H04W8/02 ,  H04W8/26 ,  H04B7/26

公开(公告)号：HK7795A

公开(公告)日：1995-01-27

申请号：HK7795

申请日：1995-01-19

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.

公开(公告)号：BR9401518A

公开(公告)日：1994-12-27

申请号：BR9401518

申请日：1994-04-18

Applicant: IBM

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

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.

公开(公告)号：DE3788649T2

公开(公告)日：1994-06-23

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.