International Business Machines Corporation

Ibm Canada Limited - Ibm Canada Limitee

Murray C Baker

Roger Y Cheung

Mahmoud Naghshineh

Peter E Reissner

Partha P Bhattacharya

Arvind Krishna

John V Taglione

Danny N McKay

Jeane S Chen

Nelson Jean

Partha Pratim Bhattacharya

Alan C Chau

David Newton

Daniel Y Wong

Eduardo M Kolbe

Roberto M Kobo

Rupam Sinha

Aron D Wallaker

Charles E Perkins

The invention provides a method for communication between a plurality of stations in a communication network using media access protocol, in which medium access is granted to stations obtaining a successful reservation of the medium and in which data transmission verification is performed by the protocol within the reservation. In the method a station sends a request message on the communication medium for a reservation of the medium to a recipient station in the network. The recipient station sends a reservation confirmation message back to the sending station which receives it and responds to the reservation confirmation message by sending an ordered sequence of data frames to the recipient station. After sending the ordered sequence of data frames the sending station sends an end of transmission message to the recipient station, which replies by sending back an end of transmission confirmation identifying the number of frames received in their original sequence. If the number is not correct remedial action can be taken by the sending station to resend missing data. Address conflict resolution is also provided by another aspect of the invention. The invention has embodiments which handle unicast and groupcasting transmissions.

Data link layer extensions to a high latency wireless MAC protocol

A method and means for information transmission over a medium for a wireless communication system comprising a network of stations capable of sending and receiving data transmissions over a number of communication channels. The method includes sending a data transmission in a packet including a header and a data portion, the header includes identification (ID) of the network; identification of the next channel to be used in communications; an address; a channel busy count field; and a network command.

Channel hopping protocol

A method and apparatus for providing a three-way connection between a mobile computing device, a stationary computing device and a computer network. When there is an established connection between a mobile computing device (e.g. a notebook computer) and the stationary computing device (e.g. desktop PC) over the wireless communication channel (e.g. infrared link), the system operates in BRIDGE mode. In BRIDGE mode the system redirects information packets in the OSI layer 2 (data link layer). When a notebook computer is not attached, the system operates in PASSTHROUGH mode and all non-broadcast message traffic from the Ethernet LAN is filtered by the Ethernet adapter based on the network address or group address of the desktop PC.

Method and apparatus for providing a 3-way connection between a mobile

An internetworking node for providing internetworking services for mobile wireless nodes is disclosed. Each mobile wireless node is associated with at the most one internetworking node. Each mobile wireless node selects which internetworking node it will associate with. The internetworking node will then act for all wireless nodes associated to it in relaying messages between wireless nodes or between a wired LAN and the wireless nodes. A tracking mechanism for such a system which maintains a table of all the internetworking nodes the wireless node has recently heard and deleting all such internetworking nodes which have not been heard recently is disclosed. A switching mechanism for such a system for determining when the wireless mobile node should switch its association from one internetworking node to another is also disclosed. The switching mechanism determines whether a particular internetworking node overheard by the mobile wireless node has been heard recently, and if not will associate with such an internetworking node. Otherwise the wireless node maintains its current association, with a particular internetworking node until a failure to communicate occurs or the said tracking mechanism deletes its reference to the said internetworking node.

Access point for mobile wireless network node

In communication systems which include high speed wired local area networks (LANs) and low speed wireless LANs, the bandwidth of the wireless LANs can be severely impacted. It has been found that many broadcast or multicast messages which are forwarded to the wireless LANs are not required as the mobile terminals which would receive the messages are not required to act on them. The present invention provides a means and method to filter out unneeded messages so that they do not impact the bandwidth of the wireless network. Each access point for each wireless LAN maintains a table of parameters for each associated mobile terminal in the connected wireless LAN. The parameters in that table are compared to the parameters in message frames received by the access point and only those messages having parameters found in the table are put on the wireless LAN. The level of filtering can be controlled by specifying which parameters are to be used for filtering messages. The tables at each access point are maintained current by moving table entries from access point to access point as mobile terminals move from wireless LAN to wireless LAN and by removing inactive table entries from the table when a predetermined interval of inactivity is encountered and a terminal is determined to be no longer in active contact with the access point.

Broadcast/multicast filtering by the bridge-based access point

A method of routing packets through a fixed source routing communications network from and to mobile units. With this invention an initial access point is determined when a communications session is established to or from a mobile unit through the network. Location information is updated each time the mobile unit moves out of the range of one access point and into the range of another access point of the network. When packets for the session are to be transmitted to the mobile unit from the wired network, the packets are forwarded from the initial access point to a current access point, which by definition is in the range of the mobile unit. When packets for the session are to be transmitted from the mobile unit and to the wired network, the access point intercepts these packets and routes them to their destination and/or initiates route discovery to those destinations. When packets are to be transmitted between mobiles at different access points. The packets are sent between the current access points and not through the home access points.

Mobility enabling access point architecture for wireless attachment to

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Toronto, Canada

Murray C Baker