摘要:
Deciphering and verification of the checksum of enciphered and encapsulated UDP datagrams, particularly those which enclose a tunnelling protocol such as L2TP, are achieved by the provision of a checksum verifier in parallel with a decipher block. Checksum logic creates a pseudo UDP header needed for checksum verification using fields that would occur at the start of the packet that encapsulates the UDP datagram. The first part of the packet to be deciphered is the UDP header; checksum logic can latch the checksum field into a local register. As the rest of the packet is deciphered the checksum verifier processes the data at the same time. Eventually the checksum logic will acquire a complete checksum which can be compared with the checksum that had been previously latched, so as to verify the checksum.
摘要:
A variable attenuation device for optical signal transmission has first and second ferrules or plugs having abutting end faces, one of the ferrules being rotatable with respect to the other while axial alignment therebetween is maintained. Each ferrule or plug has an axial bore aligned with the other and contains the end of an optical fiber, with a fiber having a smaller diameter than the diameter of the bore in which it is contained so that the fibers may have decreased engagement with each other when there is relative rotation of the ferrules although the ferrule bores remain aligned.
摘要:
A network router has a distributed processing scheme for multicast packets. The router has a look-up and forwarding engine operative in response to the reception of an internet protocol multicast packet to direct the packet to a multiplicity of transmit ports which may or may not be connected to the source network segment from which the multicast packet was received by the router. Each transmit port is associated with a predetermined default network segment and the engine directs the packet to the ports (e.g. across the router's backplane) with an identification of the source network segment and control flags which enable processing means associated with the ports to determine by comparison of the respective network segment and the source network segment whether the packet is bridged from the respective port or routed, with relevant modification of the packet, from that port. The control flags comprises a first flag which can be set to allow the relevant modification and a second flag which can be set to allow the comparison between the source segment and the predetermined default segment.
摘要:
A system and method for designing schematic diagrams of electronic circuits is provided. A library of electronic components represented in graphical form are selectable by a user for inclusion into a schematic diagram. The components are connected together to define a circuit that performs a function. In order to simulate and test a particular portion of the circuit rather than the entire circuit, the present invention provides a disabling routine that disables portions of the circuit not to be included in the simulation. The present invention allows a circuit designer/tester to focus on desired areas of a circuit while ignoring others.
摘要:
A system and method for designing schematic diagrams of electronic circuits is provided. A library of electronic components represented in graphical form are selectable by a user for inclusion into a schematic diagram. The components are connected together to define a circuit that performs a function. In order to simulate and test a particular portion of the circuit rather than the entire circuit, the present invention provides a disabling routine that disables portions of the circuit not to be included in the simulation. The present invention allows a circuit designer/tester to focus on desired areas of a circuit while ignoring others.
摘要:
Deciphering and verification of the checksum of enciphered and encapsulated UDP datagrams, particularly those which enclose a tunneling protocol such as L2TP, are achieved by the provision of a checksum verifier in parallel with a decipher block. Checksum logic creates a pseudo UDP header needed for checksum verification using fields that would occur at the start of the packet that encapsulates the UDP datagram. The first part of the packet to be deciphered is the UDP header; checksum logic can latch the checksum field into a local register. As the rest of the packet is deciphered the checksum verifier processes the data at the same time. Eventually the checksum logic will acquire a complete checksum which can be compared with the checksum that had been previously latched, so as to verify the checksum.
摘要:
A device and method for measuring changes in denier, percent finish-on-yarn, interlacing of polymer fiber, and other fiber properties, in real time as the fiber is being manufactured. The device uses an electrode driven at a discrete voltage to induce a current which changes in amplitude and/or phase in response to changes in denier, finish-on-yarn and/or interlacing of a fiber. A sensing system samples the current and detects changes in the amplitude and/or phase. A computer, running an application program, quantifies the change and determines the applicable property.