Abstract: A communications apparatus is capable of being disposed in-line in a communications link that supports a main communications channel. The communications link connects a first host to a second host. The communications apparatus comprises an application logic that supports a sub-channel within the main channel. When the main channel is potentially faulty, the application logic is arranged to monitor the main channel to determine an error condition and send a message by replacing data reserved for control purposes in order to communicate the error condition as sub-channel data.

Abstract: Aspects of the disclosure embody a multi-master two-wire serial bus that comprises two or more chained two-wire serial busses. The chained two-wire serial busses include a host two-wire serial bus with a first master device and one or more slave devices. One or more chained two-wire serial busses are coupled to the host bus wherein one or more slave devices on the host two-wire serial bus operate as second master devices, which comprise a digital state machine including a two-wire serial slave component coupled to the master device and a two-wire serial master component coupled to the slave devices on the chained two-wire serial bus. The digital state machine emulates a slave device on the host two-wire serial bus and a master device on the chained two-wire serial bus.

Abstract: A method for real time monitoring of at least one TCP flow involves monitoring TCP packets flowing past a particular point in a TCP network. A flow trace including at least source and destination addresses for each TCP packet is determined and a packet record for each monitored TCP packet within a determined flow trace is created. Each of the packet records includes at least a transmitted order number and an actual received sequence number, from which an expected received sequence number for each packet record is determined and stored in the packet record. The difference between the expected received sequence number for each packet record and the expected received sequence number for the previous packet record is used to thereby determine by how much a particular packet was moved out of sequence.

Abstract: A method of testing optical network equipment involves plugging a tester device into a standard electrical socket on the optical network equipment to be tested. The tester device communicates with the optical network equipment to be tested via the standard electrical socket, appearing to the optical network equipment as though it was an optical transceiver that would be plugged into the standard electrical socket in normal use. The tester device thus has a plug with the same physical and electrical properties as the optical transceiver, and uses the same electrical signaling protocols and or formats that are used by the optical transceiver.

Abstract: An in-line network simulator is provided that disrupts packets traveling through it to simulate network conditions. According to one embodiment, a method comprises receiving, at an in-line network simulator, packets sent from a source node to a destination node. The in-line network simulator classifies the received packets into respective ones of a plurality of different classifications, and disrupts the received packets based on corresponding disruption characteristics defined for their respective classifications. Such disrupting of the packets may include selectively performing at least one of delaying, dropping, and reordering of the received packets.

Abstract: By equipping receiving devices in a network with synchronizable clocks it is possible to periodically send an “impulse” signal that is received by all of the clocks at the same (or relatively the same) instant of time. The accuracy of the impulse clock need not be high, only that its signal reach all the clocks approximately at the same time. In one embodiment, a transmitting device, upon receipt of the synchronizing impulse signal, sends a packet of data bearing the sending device's epoch time-stamp to a receiving device. The data packet makes its way through the network element to the receiving device and the time-stamp is used by the receiving device to calculate the difference between the epoch time of the receiver and the epoch time of the sender. Effectively, this procedure removes the unknown network element transit times from the equation and allows the devices to operate in a synchronized manner.

Abstract: Arbitrary numerical distributions are presented for use in devices having limited processing and storage capabilities by having the device accept strings of arbitrarily distributed numbers from a source outside of the device. In one embodiment, a master controller creates a table of values which follow the desired minimum, maximum, mean, and standard deviation, etc. of the particular desired statistical distribution required. The created table is then communicated to the limited capacity device and can be used whenever a distribution of random values is required. The master controller could have one of several slave devices associated with it in the system. In another embodiment, where the storage capability of the device is large enough to store a table of values with sufficient different entries to create a distribution of satisfactory “randomness” for the particular application, a random number generator within the device is used to select the order of presentation of the table of values.

Abstract: A monitoring system comprises a first network probe coupled to a first point in a communications link and a second network probe coupled to a second point in the communications link. Each of the first and second network probes is arranged to sample packets from a predetermined flow of packets and store timestamps associated with packet samples. The timestamps stored by the probes are subsequently correlated.

Abstract: A tether assembly includes a tether cable containing optical fibers and adapted to be attached to a fiber optic distribution cable at a mid-span access location. A furcation at the end of the tether cable separates and transitions the optical fibers into furcation legs terminating in individual connector ports. Each connector port may be a receptacle for receiving a connector mounted upon one of the optical fibers and a mating connector of a drop cable, a plug mounted upon one of the optical fibers that is received within a plug alignment member operable to align the plug with a mating plug of a drop cable, or a connector that is routed to a receptacle disposed within an external wall of a network connection terminal from within the enclosure. The tether assembly provides a distribution cable assembly and method for mitigating a span length measurement difference in a pre-engineered communications network.

Abstract: A network element is provided with the capability to perform monitoring and/or measurement functions on the element and the network of which it is a part. The monitoring/measurement functionality is implemented by programmable devices to enable the functionality to be modified and updated without removing the network element from service.

Abstract: A tester for testing communication links in a network which carries data frames between communications ports having respective station addresses includes a plurality of communications ports and a test data generator for generating test data frames to be transmitted via the communications ports. A store holds a plurality of sets of predefined station addresses to be associated with the communications ports. A selector receives an indication of user selection of one of a plurality of test modes of the tester, and selects in accordance with that indication a respective one of the sets of predefined station addresses for association with the communications ports. The selector may also receive an indication of user selection of one of several test modes, and select a respective mode of operation of the communications ports and of the test data generator.