Abstract: A method of operating in a network in which stations communicate over a shared medium is described. The method provides regularly repeated contention free intervals, CSMA communication during times outside the contention free intervals, and distributed control over the initiation and makeup of the contention free intervals to a plurality of stations so that any of the plurality of stations can independently initiate transmission within the contention free interval.

Abstract: A system and method is described for reliably transferring a node in a communications network from one Logical Network to another Logical Network. The system and method is reliable and robust with respect to potentially varying implementations of host devices in the communications network, and is compatible with other network management operations as specified in HomePlug Specifications.

Abstract: Media Access Control (MAC) layer transmit and receive buffering with multi-level prioritization. The receive buffering allocates receive buffers for receiving frame data from a PHY interface in priority order using both a static and dynamic buffer allocation, and delivers completed buffers queued in a multi-level priority queue to a host interface highest priority first. The transmit buffering delivers completed buffers queued in a multi-level priority queue to the PHY interface in priority order. When the multi-level priority queue contains a buffer that is higher priority than one being prepared for transmit, a priority-based interruption causes the transmit processing of the buffer to be suspended at its current state with the higher priority buffer taking its place. Upon completion of the higher priority buffer, the suspended buffer is resumed at its current state.

Abstract: In a powerline network, a power line node device coupled to a host bridge application detects a “jam packet” in response to an attempt to pass a frame to the host bridge application. The powerline node device uses internal logic to override a conventional ARQ response to this and subsequent frames, in particular, when such frames are of the type for which a response is expected, with an automatic FAIL response for a predetermined time interval.

Abstract: A transmit process that limits the time during which a reduced network bandwidth exists between two powerline nodes because a receiving node fails to respond to frame transmission attempts by a transmitting node is described. The transmit process restricts the number of retries that occur in a lower date rate transmission mode and, for a predetermined time period to follow, drops all subsequent frames destined for the non-responding node.

Abstract: A robust Media Access Control (MAC) scheme for network stations operating in an OFDM transmissions network. The MAC scheme uses robustly transmitted frame control information to ensure network synchronization (for media access) and convey channel access prioritization for QoS. Frame control information can occur in a frame before and after the frame's payload, or in a response.

Abstract: A source-aware bridging scheme for supporting bridging between a noisy (“unreliable”) network and another, reliable network. Each device connected to the medium of the unreliable network includes a source-aware MAC that maintains a Bridge Proxy Destination Address list (BPDAlist) of all destination addresses that reside on the other network and are reached by a bridge. The BPDAlist information can be learned by the source-aware MAC during a frame receive and/or received during a channel estimation cycle. The list associates destination addresses with the address of the particular bridge through which the destination addresses are accessed. The bridge serves as a proxy with respect to those destination addresses and thus maintains its own list of the destination addresses for which it serves as proxy, or, IAPlist. The IAPlist can be learned, or passed down to the source-aware MAC from a learning bridge process or from the local host to which the device is coupled.

Abstract: A partial ARQ protocol for multicast and broadcast transmissions in network devices operating in a shared medium access network. To support the partial ARQ, a media access control (MAC) protocol uses robustly transmitted frame delimiters and a MAC management frame structure. In a multicast or broadcast frame with partial ARQ, a destination address field is set to that of a selected proxy device's address, and the address of the intended recipients (of group address of the intended recipients) is placed in an entry in the MAC management frame structure. The frame also contains a multicast flag set to indicate that the transmission is intended for more than one device and a value in the frame delimiters to indicate that a response is requested. Upon receipt of such a frame, the proxy device specified by the destination address field provides an appropriate response type on behalf of the group.

Abstract: A printing apparatus having a moving carriage with a snap action switch mounted thereon to initialize the left and right margins of the printing apparatus. The carriage is moved to the left until the snap action switch strikes a stop on the frame of the machine. The carriage is then moved a predetermined distance to the right, and a left margin counter is set to zero while a right margin counter is set to a count representative of the width of printing between margins. The counters are incremented and decremented by movement of the carriage with the zero point of each counter representing presence of the carriage at that associated margin. Manual devices are provided for setting a narrower printing field with wider margins at either side by resetting the margin counters. Also, a margin release allows movement of the carriage outside of the narrowed printing field but never outside of a maximum printing field.