Nec Usa, Inc.

Nec Corporation

Arup Acharya

Jun Li

Dipankar Raychaudhuri

Rajiv S Dighe

Ruixi Yuan

Subir K Biswas

Mobile terminal handoff control is provided for point to multipoint (PMP) connections in Mobile ATM networks. Special issues for the handoff control in all three types of PMP connections are taken care of, including cross over switch discovery and handoff path re-routing. A protocol for a PMP connections signaling mechanism is presented, which works with all three types of PMP connections and has a lossless control function. The PMP connection tree topology is protected.

Handoff control for point to multipoint connections in mobile ATM networks

In a method of transmitting an IP packet between a source and a destination through an ATM network which has a node formed by an ATM switch and a packet router, a reception packet or cell is transmitted to the node on an unused or undefined VC and is sent to the packet router in the node. In the packet router, an output port is selected by the use of the unused VC to establish a switched virtual channel in the ATM switch and to transfer each packet through the switched virtual channel after the switched virtual channel is established, as long as the reception packet is sent on the same VCI. Neither signaling nor protocol is needed between the nodes.

System and method of transferring internet protocol packets using fast ATM cell transport

A handoff control process in a wireless ATM network replaces an old communications connection with a new communication connection. In order to guarantee that no data is lost during the replacement process, an ATM cell level mechanism is used to re-schedule the buffering and transmitting of data streams of the virtual channels (VCs) to be handed-off. In addition, this mechanism is transparent to user applications. The present invention performs three fundamental cell level scheduling functions. The first function is to mark and redirect cell transmission with operation and maintenance (OAM) cells. The second function is to disable and buffer cell transmission until the new path is connected. The third function is to enable cell transmission, starting with the buffered cells across the connected new path.

Handoff method for an ATM wireless network wherein both the switch and

Mobility in a wireless ATM network is accomplished by use of hand-off control protocols. A mobile terminal signals a first base station that a hand-off is to occur. In a first preferred embodiment the first base station signals a second base station requesting a hand-off. After the second base station signals the first base station that a datapath link is available from a hand-off switch to the second base station, the hand-off switch causes the datapath to change from the first base station to the second base station and the first base station signals the mobile terminal to commence communication with the second base station. In a second preferred embodiment, the mobile terminal signals a first base station that a hand-off is to occur. The first base station signals a second base station requesting a hand-off. At the same time a datapath link is established between the first and second base stations. When the second base station signals the first base station that the datapath link is available, the first base station signals the mobile terminal to change to the second base station and data is sent from the first base station to the second base station via the available established datapath link.

Handoff-control technique for wireless ATM

A method for transporting Internet Protocols (IP's) over an Asynchronous Transfer Mode (ATM) network that exhibits the strengths of ATM, namely packet interleaving (using cell-based transport) with Quality of Service support for connection-oriented traffic (such as multiclass native ATM traffic and flows-based IP traffic using RSVP), while optimizing the connectionless requirements of existing IP traffic. Advantageously, both the IP protocol stack and ATM protocol stack operate as peers over ATM cell transport hardware. The method exploits an 'implicit' signaling/control phase characteristic of IP traffic/protocols thereby minimizing setup. The implicit signaling phase is used to map a flow from a routed path to a switched path immediately upon transmission of a first packet. Similarly, particular packets may be immediately transported over the routed path even after establishment of the switched path. This mapping from the routed path to the switched path and vice versa is based upon the structure/semantics of the protocol driving the flow and not just the duration of the flow as done with prior-art methods. Consequently, while prior-art methods require cell-level counters to monitor activity (or lack thereof) for switching state, the method uses explicit control messages and soft-state at the IP level (as opposed to the cell level) to do the same. Advantageously, the method imposes no switching overhead as there is no coordination between neighboring nodes when a flow is moved from the routed path to the switched path.

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North Brunswick, NJ, United States of America

Arup Acharya