Abstract: The present invention provides a method and apparatus for scalable server clustering. In one embodiment, a plurality of servers service client requests. In one embodiment, responsibility for servicing a client is assigned to a primary server. Requests from the client are routed to the primary server. In one embodiment, the primary server is selected for a client using a round-robin method. In another embodiment, a server monitors how many clients it serves as a primary server. If a client is to be assigned a server as a primary server and the server determines that it is assigned to a sufficient number of clients, the server can select a different server to serve as the client's primary server. In one embodiment, an alternate server is assigned to the client. If the primary server is unavailable, the alternate server becomes the primary server and a new alternate server is selected.

Abstract: The present invention provides a method and apparatus for compound request processing. In one embodiment, a server maintains a cache of data items it has provided to a client. When the client requests a data item from the server, the server retrieves the data item and also retrieves all available associated data items. The server determines which associated data items are unchanged. Then, the server transmits the data item along with information indicating whether associated data items are unchanged. In one embodiment, when a client wishes to request an associated data item, it first determines whether the server indicated that the associated data item is unchanged. If the associated data item is unchanged, the client uses the copy of the associated data item in the client's cache. If the associated data item is changed, the client requests the associated data item from the server.

Abstract: Embodiments of the present invention relate to an adaptive transport protocol (ATP). A uniform datagram protocol (UDP) is used by one or more embodiments of the present invention to transmit the ATP data across a medium. When packets are lost and subsequent packets are received, the subsequent packets do not need to be re-sent if the lost packets later arrive, as in TCP/IP. One embodiment of the present invention builds an expected acknowledge time into the ATP data on top of the existing UDP protocol. The expected acknowledge time may be applied to every packet transmitted through the medium. When the expected acknowledge time in the medium changes, for instance if another transmission enters the shared environment or the characteristics of the transmission medium otherwise change, the expected acknowledge time is modified. If some of the packets in the window are not received by their expected acknowledge times, those packets are re-sent and the complete window of packets is re-ordered.

Abstract: A method and system for providing location-based information services to a requesting user. A subscriber unit transmits an access request message comprising an identification number to one or more receiving sites on a response channel. A forward channel message is sent to the subscriber unit, the forward channel message comprising the identification number of the subscriber unit and data defining the time slot for transmission of a response message. A response message comprising an information service request and a location signal is transmitted from the subscriber unit and received at at least three receiving sites during the time interval identified by the forward channel message. The time difference of arrival of the location signal is used to determine the location of the subscriber unit. Thereafter, an information service message is generated which is responsive to the information service request and the location of the subscriber unit and transmitted to the subscriber unit on the forward channel.