Abstract: An arbitration mechanism provides quality of service guarantees for time-sensitive signals sharing a local area computer network with non-time-sensitive traffic. Device adapters are placed at all access points to an Ethernet network. The device adapters limit admission rates and control the timing of all packets entering the network. By doing so, collisions are eliminated for time-sensitive traffic, thereby guaranteeing timely delivery. A common time reference is established for the device adapters. The time reference includes a frame with a plurality of phases. Each of the phases is assigned to a device adapter. Each device adapter is allowed to transmit packets of data onto the network only during the phase assigned thereto. The length of the phases may be modified in accordance with the number of packets to be transmitted by a particular device adapter. A master device adapter may be appointed to synchronize each of the device adapters.

Abstract: An apparatus and method for determining the QoS of a communication system. In one embodiment a service verification equipment device (SVE) is placed into the communications link between the wide area network and the transmitting customer premise and an SVE is placed into the communications link between the wide area network and the receiving customer premise. The transmitting SVE inserts a test cell into the customer's data stream over communications link which informs the receiving SVE that a test is commencing. After a predetermined number of customer data cells are sent, the transmitting SVE inserts a termination cell into the communications link at the end of the test. The receiving SVE then compiles data related to the QoS of the communications link and that data is analyzed to determine the QoS.

Abstract: A switch for connecting a peripheral device to a downstream USB device includes a plurality of peripheral interfaces operably connectable to respective peripheral devices; a USB downstream interface operably connectable to the downstream USB device, where the downstream interface is adapted to simulate insertion and removal of an upstream USB device; and a switcher for selectively establishing communication between a desired peripheral interface and the USB downstream interface.

Abstract: A network system for providing efficient transmission of real-time data and non-real-time data between a plurality of network devices, including an arbitration mechanism that provides a low cost and high performance mechanism for delivery of quality of service guarantees for time-sensitive data sharing a local area with non-time-sensitive data. Device adapters are placed at all access points to a local network. The device adapters limit admission rates and control the timing of all packets entering the network. An X-Hub placed at the center of the network provides for transparent, concurrent transport of signals transmitted by device adapters. Collisions may therefore be eliminated for time-sensitive traffic, thereby guaranteeing timely delivery. A common time reference is established for the device adapters and the X-Hub. The time reference defines a frame with a plurality of phases. Each of the phases defines a state of the X-Hub, and a state for each of the device adapters.

Abstract: A data transmission system includes probes connected between end user sites and a data switching network. Each probe is connected to the switching network via an access channel wherein transmission circuits establish paths between the sites through the access channel and switching network. The probes capture and retransmit data traveling between the sites over respective transmission circuits, and can thereby insert service level analysis (SLA) messages into the data traffic in order to actively communicate network performance information to other probes. For each transmission circuit, the probes periodically collect measurements related to one or more network performance metrics, including: round-trip delay (RTD), data delivery ratio (DDR) and network availability. During each SLA measurement cycle, a sequence of SLA messages is exchanged over each transmission circuit, which messages contain data used to determine RTD and DDR.

Abstract: An antenna enclosure comprising building elements and a support structure is disclosed. The enclosure is designed to be substantially transparent to electromagnetic waves and to have the appearance of the surrounding architecture or locale so that the antenna does not cause an obtrusive visual distraction.

Abstract: A data multiplexer system is comprised of a space division multiplexer having a plurality of space divided (SDM) input channels, each SDM channel adapted to carry a first number of time divided TDM channels at a first clock rate; at least one digital data source; apparatus for generating a second clock rate derived from the first clock rate, which is at the clock rate of the data source; apparatus for selecting data from the one source in synchronism with the second clock rate; and apparatus for applying the selected data to at least one of the SDM channels; whereby data from a digital data source having a clock rate either the same or different from the clock rate of a TDM channel may be applied to and be carried by any SDM channel.