77 results about "Frame check sequence" patented technology

The present invention discloses an interfacing apparatus and method for adapting Ethernet directly to physical channel, which encapsulates MAC frames into SDH/SONET SPE/VC using LAPS. The LAPS encapsulation consists of the start Flag Sequence, address field (SAPI, Service Access Point Identifier), control field (0x03), Information field (Ipv4, Ipv6, or PPP protocol data unit), FCS (Frame check sequence) and the ending Flag Sequence. The Flag Sequence (0x7E) identifies the beginning/end of a LAPS frame. The present invention can be used to provide Ethernet interface in telecom SDH/SONET transmission device or provide facilities to remote access datacom device, such as core and edge routers, switch devices, IP based network accessing equipment, line cards, and interfacing units used in high speed application, e.g. Gigabit applications. By simplification of SDH/SONET, i.e. using simplified SDH/SONET, Ethernet could be applied to DWDM.

An improved method and system for generating a frame check sequence. A multiple-bit data string, M, is received in which M is of the form:M is thereafter parsed into multiple subframes of the form:andThe subframes are padded with zeros resulting in subframes of the form:andA partial check sum is then generated for each of the multiple subframes. Finally, each of the partial check sums are added together such that a frame check sequence for M is obtained.

A mobile ad-hoc network (MANET) may include a plurality of nodes for transmitting data therebetween using a media access layer (MAC), where each of the nodes has a respective MAC address associated therewith. The MANET may also include a policing node for detecting intrusions into the MANET by monitoring transmissions among the plurality of nodes to detect frame check sequence (FCS) errors from a MAC address, and generating an intrusion alert based upon detecting a number of FCS errors for the MAC address exceeding a threshold. The policing node may also detect intrusions based upon one or more of failed MAC address authentications, illegal network allocation vector (NAV) values, and unexpected contention or contention-free operation.

A method and apparatus are described for creating a multi-media stream (e.g., video, voice, audio, etc. . . . ) Super-MAC frame in a physical protocol data unit, including inserting a physical layer header into a channel time allocation and generating the multi-media stream SuperMAC frame further including, appending a media access control header after the physical layer header, calculating a header correction code, appending the header correction code after the media access control header, appending a media access control multi-media stream payload from a transmit queue, calculating a frame check sequence, appending the frame check sequence after the media access control multi-media stream payload and repeating the above acts, after inserting the physical layer header, until one of the channel time allocation is full or all transmit queues are empty.

A method of transmitting a data frame is disclosed and may include transmitting a preamble, transmitting a physical layer convergence protocol (PLCP) header, and transmitting a plurality of MAC protocol data units (MPDUs). Each MPDU may be configured to reset a convolutional decoder state after each MPDU. The method may also include transmitting an MPDU aggregation header. The MPDU aggregation header may include a count of packed MPDUs, an array of offsets, an array of lengths, a frame check sequence (FCS) for the MPDU aggregation header, a group of tail bits, or a combination thereof. Further, an end of the MPDU aggregation header may be aligned to an interleaved symbol boundary.

To allow performance monitoring of the end-to-end path from the Ingress node to the Egress node of the GFP network by an FCS (Frame Check Sequence) check in a GFP (Generic Frame Procedure) frame, the FCS generation target area is set in the payload field of the GFP frame, no FCS recalculation is performed at the relay node and the GFP frame is transferred to the next node with the FCS added when the GFP frame is received even if an error is detected by the FCS check.

A high speed communications interface divides data into a plurality of lanes, each lane encoded with clocking information, serialized, and sent to an interface. During cycles when there is no available data to send, IDLE_EVEN and IDLE_ODD cells are sent on alternating cycles. Data is transmitted by sending a header which spans all lanes and includes a START symbol. The final data transaction includes a Frame Check Sequence (FCS) which operates over the entire header and data. The packet is terminated by an END symbol, which is sent after the final data, and the remainder of the lanes are padded with IDLE_EVEN, IDLE_ODD, IDLE_EVEN_BUSY, or IDLE_ODD_BUSY cycles. The interface has a variable clock rate.

Provided is a method of generating a data frame used in a wireless personal area network (WPAN). The method of generating a data frame used in a wireless personal area network (WPAN), the method including: generating a plurality of sub frames by using one or more MAC service data units (MSDUs); and generating sub headers including information about each sub frame; generating a PHY service data unit (PSDU) by using the plurality of sub frames, the sub headers, and a MAC header, wherein each sub frame includes a frame check sequence (FCS) field for detecting an error of a corresponding sub frame.

A medium access control (MAC) frame provision method establishes security in an IEEE 802.15.4 network. A MAC frame is generated, which includes a MAC header, a payload field, and a frame check sequence (FCS) field, the payload field including relevant main data according to a frame type defined in the MAC header. A disguised decoy data sequence number (DSN) is generated and inserted into the MAC header. A real DSN, which is a corresponding transmission sequence number of the MAC frame, is generated and inserted into the payload field. The MAC frame is transmitted, including the encrypted payload field, to a counterpart node. A MAC ACK frame acknowledges reception of the transmitted MAC frame; and a DSN is compared in the received MAC ACK frame with the real DSN. An authentication of the counterpart node is performed when the received MAC ACK frame is equal to the real DSN.

Provided is a method for adjusting Fast Fourier Transform (FFT) window positioning in a Multi Band Orthogonal Frequency Division Multiplexing Ultra-Wideband (MB-OFDM UWB) system. The method includes the steps of acquiring an initial FFT window position and a frequency hopping position, demodulating a received signal by using the initial FFT window position and the frequency hopping position acquired in the acquiring step, transmitting received data information to a Media Access Control (MAC) layer with a reception frame (RX frame) structure and judging at the MAC layer whether or not a packet error is occurred based on Frame Check Sequences (FCSs), and if no packet error is occurred, returning to the demodulating step, and if the packet error is occurred, changing a register map by using a predetermined interface line in a MAC-physical layer (MAC-PHY) interface to thereby adjust the FFT window position and the frequency hopping position, and then returning to the demodulating step.

Data error often occurs during the process of data transmission or storage. Typically, a store-and-forward data switch uses the frame check sequence portion of a data frame to detect for error that occurred during transit to the switch. However, error could be introduced into the data frame when it is in the memory of the data switch. A network switch capable of single-error correction and double-error detection is provided to further protect the data frame while it is in the switch.

A wireless local or metropolitan area network may include a plurality of stations for transmitting data therebetween using a media access layer (MAC), where each of the stations has a respective MAC address associated therewith. The wireless network may also include a policing station for detecting intrusions into the wireless network by monitoring transmissions among the plurality of stations to detect frame check sequence (FCS) errors from a MAC address, and generating an intrusion alert based upon detecting a number of FCS errors for the MAC address exceeding a threshold. The policing station may also detect intrusions based upon one or more of failed MAC address authentications, illegal network allocation vector (NAV) values, and unexpected contention or contention-free operation.

The invention discloses a data encapsulation method for receiving side and sending side of a transmission apparatus and a synchronous digital system thereof. The encapsulation method for the receiving side comprises: A. identifying the protocol domain type of received data frame; B. acquiring play-load in the data frame; C. adding protocol domain type indication, source media access control sublayer protocol address and target media access control sublayer protocol address to the head of the play-load successively; D. calculating frame check sequence and adding the result to the tail of the play-load to form the Ethernet standard data frame. The method for encapsulating datum communicating among equipment net elements provided by the invention insures the route transmitting carried out by the hardware chip and reduces CPU load by encapsulating MAC address in the data frame and using Ethernet format in datum communicating among equipment net elements.

A DSL device performs a frame check sequence operation in a digital signal processor (DSP), i.e., layer one of the OSI seven layer model, heretofore performed only in layer two of the OSI seven layer model. Performing the layer two framing and calculating the frame check sequence in the DSP allows the DSP to use the layer two error detection results, and optionally, the mean squared error vector, to more accurately determine whether to update adaptive receiver parameters.

A system and method, associated with a receiver, for increasing the range or bandwidth of a wireless digital communication network and a receiver incorporating the system or the method. In one embodiment, the system includes: (1) a service class detector configured to determine a service class of a PDU received by the receiver from the wireless digital communication network and (2) a frame check sequence checker coupled to the service class detector and configured to disregard error-checking information in the PDU when the service class indicates that the PDU is a streaming media PDU.

The invention relates to the field of optical fiber communication, in particular to a method for acquiring wavelength values by remote equipment in a wavelength division multiplex-Ethernet passive optical network (WDM-EPON) passive optical network system. The key points of the method comprise that: the wavelength values of an optical network unit (ONU) uplink sending signal are filled in 31 byte filling domains between the 'synchronous time' field and the 'frame check sequence' field in a discovery message frame in IEEE802.3ah; and ONU transmits the message to an optical line terminal (OLT) according to the wavelength values of the ONU uplink sending signal filled in 31 byte filling domains. The method can correctly allocate the wavelength values of the uplink sending signal to the ONU which is not discovered by the OLT in the WDM-EPON mixed passive optical network system, so that the ONU can be registered successfully.

A communication device (1001) is provided. The communication device (1001) can include a transceiver (1003), for transmitting and receiving communications when operably connected to a communication network. Also, the communication device (1001) can include a processor (1009) cooperatively operable with the transceiver (1003). The processor (1009) can facilitate receiving (1015) one or more frames from a transmitting device. Also, the processor (1009) can obtain a frame check sequence result (1019). Before obtaining the frame check sequence result, the processor can initiate (1017) a transmission of a responsive frame corresponding to the one or more frames. The responsive frame will explicitly indicate an acknowledgement (ACK) or negative acknowledgement (NAK) of the one or more frames.

A system for embedding metadata in data packets has logic that is configured to insert metadata into a data packet after the payload data and padding, if any. The logic further adjusts the packet's overhead, such as a frame check sequence, to account for the added length of the packet. The packet remains compliant with applicable protocols, such as Ethernet, and can be successfully communicated in accordance with such protocols while carrying the metadata. In this regard, the insertion of the metadata is transparent to protocol stacks such that the metadata data does not cause an error or the protocol stacks to render the packet invalid. In particular, the protocol stacks view the inserted metadata as part of the packet's pad field, and the inserted metadata should not cause any errors in the operation of the protocol stacks or prevent the protocol stacks from processing the packet.

A system providing sound to a user, having at least one audio signal source; a transmission unit with a digital transmitter which transmits audio signals via a wireless digital audio link as audio data packets, each packet having a start frame delimiter, audio data and a frame check sequence; at least one receiver unit having at least two digital receivers connected to a common processing unit and an antenna, and including a demodulator and a buffer, and a mechanism for stimulating the hearing of the user. Each receiver receives, verifies and buffers the audio data packets, and the processing unit reads an audio data packet from the buffer of one of the receivers. If the packet is correctly received by the receiver, the buffer of the other receivers is flushed, and if the packet has been incorrectly received, the audio data packet from the buffer of another receiver is read.

An embodiment of the invention provides data frame transmission method and device. By the use of the method and device, expense on data frames can be decreased and transmission efficiency can be increased. The method includes: determining a value of each bit ToDS (to distributed system) coming to a distributed system and a value of each bit FromDS (from distributed system) from the distributed system according to data transmission directional information of a site used for indicating transmission of data frames; acquiring an DA (destination address) and/or an SA (source address) corresponding to the data transmission directional information; determining an address field, which is used for carrying the DA and/or the SA, according to the data transmission directional information; determining an FCS (frame check sequence) of a data frame according to a header, a frame entity and an RA (received address) of the data frame; and transmitting the data frame comprising the ToDS, the FromDS, the address field and the FCS to a receiver. Using the address field to carry the DA and/or the SA of the data frame according to data transmission directional information decreases expense of frame headers and increases transmission efficiency, and transmission can be completed in the presence of data frame forwarding.

Described embodiments provide for a frame check sequence (FCS) module with a cyclic redundancy check (CRC) unit that receives a data block (padded, if necessary, to a maximum width) and a first state vector and computes an internal vector based on an extended CRC transition matrix. The FCS module further includes a set of matrix units, each matrix unit configured to multiply the internal vector by a corresponding correction matrix wherein the multiplications result in a set of products. A multiplexer selects, by a control signal determined by a maximum number of bytes and the original width, a second state vector from the set of products.

An HDLC accelerator includes a deframer and framer to respectively accelerate the deframing and framing processes for PPP packets. The deframer includes an input interface unit, a detection unit, a conversion unit, and an output interface unit. The input interface unit receives a packet of data to be deframed. The detection unit evaluates each data byte to detect for special bytes (e.g., flag, escape, and invalid bytes). The conversion unit deframes the received data by removing flag and escape bytes, "un-escaping" the data byte following each escape byte, providing a header word for each flag byte, and checking each deframed packet based on a frame check sequence (FCS) value associated with the packet. The output interface unit provides deframed data and may further perform byte alignment in providing the deframed data. A state control unit provides control signals indicative of specific tasks to be performed for deframing.