An adapter is configured to connect to a network. The adapter including a controller configured to receive a stream of network communication from a computer system physically connected to the adapter. The controller is further configured to detect a first identifier. The first identifier is related to a first communication unit of the stream of network communication. In response to detecting the first identifier, the controller is further configured to direct the first communication unit away from the network and back toward the controller through a loopback pathway. The controller is further configured to direct the stream of network communication away from the computer system and to the network.

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.

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 operable to receive a transmit signal, a receive port, an antenna switch, a back switch, a transmit port DC blocking capacitor coupled between a first end of the antenna switch and the transmit port, an antenna port DC blocking capacitor coupled between a second end of the antenna switch and the antenna port, a receive port DC blocking capacitor coupled between a first end of the back switch and the receive port, and a reactive loopback impedance coupled between a second end of the back switch and the first end of the antenna switch. The reactive loopback impedance provides a portion of the transmit signal to the receive port when the back switch is activated.

One embodiment is a method including configuring a first network element of a fiber channel (FC) network as a generator element, wherein the generator employs a link diagnostic protocol to cause a second network element comprising a peer of the first network element as a reflector element, wherein the first and second elements are connected via a link; entering a first diagnostic phase, wherein in the first diagnostic phase, diagnostic capabilities of the first and second elements are determined; and subsequent to completion of the first diagnostic phase, entering a second diagnostic phase in which a deep loopback test is performed, wherein the deep loopback test comprises a frame level loopback test for exposing an issue in a path between the first and second network elements beyond a Media Access Control (MAC) layer.

In a device and a method for monitoring a clock signal of a position measuring device, which is connected to sequential electronics via a data transmission channel, and the data transmission channel has a data line, via which data signals are transmittable from an interface unit of the position measuring device to an interface unit of the sequential electronics, the interface unit of the position measuring device including a pulse generation unit, by which a test pulse is able to be generated based on the time pattern of the clock signal, and is transmittable via the data line to the interface unit of the sequential electronics. The interface unit of the sequential electronics includes a pulse measuring unit, by which a pulse duration of the test pulse in the time pattern of a clock signal of the sequential electronics is measurable in a functionally reliable manner and by which a measured value representing the pulse duration is able to be output to a control unit for analysis.

Apparatus and methods for front-end systems with reactive loopback are provided. In certain configurations, a front-end system includes a transmit port that receives a transmit signal, an antenna port, a receive port, and an antenna switch connected along a transmit path between the transmit port and the antenna port. The front-end system further includes a loopback circuit including a reactive loopback impedance and a back switch electrically connected in series in a loopback path between the transmit port and the receive port. The loopback circuit provides a portion of the transmit signal to the receive port when the back switch is activated. Using reactive loopback impedance in the loopback circuit reduces an insertion loss of the transmit path relative to a configuration using resistive loopback impedance.

A network control apparatus includes a processor. The processor calculates a first OSNR corresponding to an allowable limit BER from an OSNR yield strength curve of a transmission end in a node of a transmission end. The processor acquires a reception BER of a second node of a reception end, and calculates a second OSNR corresponding to the reception BER from the OSNR yield strength curve of the transmission end. The processor calculates a first noise intensity corresponding to the allowable limit BER from the first OSNR. The processor calculates a second noise intensity corresponding to the reception BER from the second OSNR. The processor calculates a noise intensity margin, based on the first noise intensity and the second noise intensity.

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 for verifying the integrity of data transmission between a main upstream unit (10a) and a main downstream unit (20a). The method includes the implementation of the following steps: a data-processing module (11a) of the main upstream unit (10a) generates a first frame (T1) including a packet (P1) of data to be transmitted and a cyclic redundancy code (E1) of the packet (P1); encapsulates the first frame (T1) in a second frame (T2) which also includes a cyclic redundancy code (C1) of the first frame (T1); encapsulates the cyclic redundancy code (E1) of the packet (P1) in a third frame (T3); the data-processing module (11b) of the at least one auxiliary upstream unit (10b) compares each of the cyclic redundancy codes (E1) extracted from the first frame (T1) with those extracted from the third frame (T3); and confirms the integrity of data transmission to the main downstream unit (20a) only if the comparison is positive.

According to embodiments of the disclosed subject matter, a system electronic device can include circuitry configured to receive a frame from a sender via a network as outbound traffic. Next, the system electronic device can return the received frame to the sender as return traffic. Additionally, a copy of the outbound traffic frame can be generated for analysis via a statistics measurement component, the statistics measurement component being local to the reflector. Further, the system electronic device can measure, via the statistics measurement component, performance parameters corresponding to the outbound traffic frame.