A method of conducting bit error rate testing of an electronic device under test using a bit error rate tester (BERT) includes configuring the BERT with one or more of jitter, noise, and timing settings to derive a desired receiver stressed eye diagram; connecting the electronic device under test to the BERT via an inter-symbol interference channel that introduces delays for creation of the desired receiver stressed eye diagram at the electronic device under test; the BERT placing the electronic device under test into a loopback mode whereby data transmitted to the electronic device under test by the BERT is transmitted back to the BERT for comparison to the data transmitted to the electronic device under test; the BERT transmitting a data pattern into the electronic device under test; and the BERT comparing the data pattern transmitted to the electronic device under test by the BERT to data received back from the electronic device under test during the loopback mode to detect a bit error rate.

A device includes a transmitter coupled to a node, where the node is to couple to a wired link. The transmitter has a plurality of modes of operation including a calibration mode in which a range of communication data rates over the wired link is determined in accordance with a voltage margin corresponding to the wired link at a predetermined error rate. The range of communication data rates includes a maximum data rate, which can be a non-integer multiple of an initial data rate.

Systems and methods are disclosed herein for determining that a diagnostic mode is enabled for a port of a switch, the port being part of a VLAN, and responsively designating a port of the plurality of ports as a loopback port, where a packet transmitted on the loopback port is forwarded according to an entry of a forwarding database. The disclosure further describes generating a layer 2 multicast index comprising an entry for the port and an entry for the loopback port, programming the forwarding database with an entry for a destination address of the switch pointing to the layer 2 multicast index, generating a diagnostic packet, and transmitting the diagnostic packet on the loopback port. Additionally, the disclosure describes determining that the diagnostic packet is received by any port of the plurality of ports, and responsively determining a network problem exists and causing a diagnostic protocol to be executed.

Systems, methods, and storage media for detecting a security intrusion of a network device are disclosed. Exemplary implementations may include a method involving, in the network device including a processor, monitor a light signal associated with a security enabled port of the network device; and in response to detecting a change in the light signal, initiate a security alert.

A test instrument or host device can apply inverse transmitter and receiver functions to data transmitted or received by an electrical and optical transponder. The inverse transmitter and receiver functions are applied to counteract internal signal conversion processes of the transponder. Forward error correction and test pattern analysis may be performed on signals received from the transponder after the inverse receiver function is applied to the received signals.

Apparatus and methods for front-end systems with reactive loopback are provided. In certain configurations, a front-end system includes an antenna port, a transmit port, a receive port, an antenna switch configured to selectively provide a transmit signal from the transmit port to the antenna port, a low noise amplifier having an input electrically connected to the antenna port and an output electrically connected to the receive port, and a loopback circuit including a reactive loopback impedance and a back switch electrically connected in series between the antenna switch and the receive port. The reactive loopback impedance includes a plurality of capacitors in series with the back switch and operable to provide a portion of the transmit signal to the receive port when the back switch is activated.

Methods and systems for an optoelectronic built-in self-test (BIST) system for silicon photonics optical transceivers may include an optoelectronic transceiver having a transmit (Tx) path and a receive (Rx) path, where the Rx path includes a main Rx path and a BIST loopback path. The system may generate a pseudo-random bit sequence (PRBS) signal, generate an optical signal in the Tx path by applying the PRBS signal to a modulator, communicate the optical signal to the BIST loopback path and convert the optical signal to an electrical signal utilizing a photodetector, where the photodetector is a replica of a photodetector in the main Rx path, and assess the performance of the Tx and Rx paths by extracting a PRBS signal from the electrical signal. The transceiver may be on a single complementary-metal oxide semiconductor (CMOS) die, or on two CMOS die where a first comprises electronic devices and a second comprises optical devices.

A device includes a transmitter coupled to a node, where the node is to couple to a wired link. The transmitter has a plurality of modes of operation including a calibration mode in which a range of communication data rates over the wired link is determined in accordance with a voltage margin corresponding to the wired link at a predetermined error rate. The range of communication data rates includes a maximum data rate, which can be a non-integer multiple of an initial data rate.

A method of determining the presence of a loopback in one or more networks comprises storing information related to a test instance; sending a loopback detection beacon (LPDB) containing information related to the test instance from a port on an originating device; monitoring the port for a predetermined time period to detect LPDBs arriving at the port during the predetermined time period; and determining whether a detected LPDB contains information corresponding to the stored information, to detect the presence of a loopback. The method may determine whether a detected loopback is a port loopback, a tunnel loopback or a service loopback. The stored information related to the test instance may be deleted if an LPDB arriving at the port and containing information corresponding to the stored information is not detected within the predetermined time period.

Aspects of the invention include calculating, by a transmitter, source cyclic redundancy code (CRC) bits for payload bits. The source CRC bits include source CRC bits for a first type of CRC check and source CRC bits for a second type of CRC check. The source CRC bits are stored at the transmitter. The payload bits and the source CRC bits for the first type of CRC check are transmitted to the receiver. The receiver performs the first type of CRC check based at least in part on the payload bits and the source CRC bits for the first type of CRC check. The receiver also calculates and stores at the receiver calculated CRC bits for the second type of CRC check. If the first type of CRC check indicates an error, a comparison of the source and calculated CRC bits for the second type of CRC check is initiated.