Abstract: Described are systems and methods of monitoring network health and traffic. Monitoring network health and traffic can include sending a request to a compute instance to trigger a response from the compute instance, monitoring, via a network virtualization device, communications from a virtual network interface card (VNIC) associated with the compute instance, storing information indicative of a last received packet by the VNIC, monitoring the stored information indicative of the last received packet to determine a health status of the compute instance associated with the VNIC, updating a table configured to track received responses from the compute instance, and notifying a downstream user of the health status of the compute instance.

Abstract: Described are systems and methods of monitoring network health and traffic. Monitoring network health and traffic can include sending a request to a compute instance to trigger a response from the compute instance, monitoring, via a network virtualization device, communications from a virtual network interface card (VNIC) associated with the compute instance, storing information indicative of a last received packet by the VNIC, monitoring the stored information indicative of the last received packet to determine a health status of the compute instance associated with the VNIC, updating a table configured to track received responses from the compute instance, and notifying a downstream user of the health status of the compute instance.

Abstract: A method is provided in which a call agent process that supports one or more Internet Protocol (IP) calls, stores to persistent memory a set of data associated with the one or more IP calls. An outage is detected affecting the one or more IP calls. Using the data retrieved from the persistent memory, the one or more IP calls are resynthesized using a device simulator process to simulate connectivity with endpoints that were participating in the one or more IP calls prior to the outage. After resynthesizing, depending on activity detected from devices associated with the one or more IP calls, the one or more IP calls are internally re-stitched/re-establishing (without signaling to endpoints) with the endpoints involved in the one or more IP calls, or the one or more calls are fully re-stitched/re-established by signaling an endpoint that was participating in the one or more IP calls.

Abstract: A method is provided in which a call agent process that supports one or more Internet Protocol (IP) calls, stores to persistent memory a set of data associated with the one or more IP calls. An outage is detected affecting the one or more IP calls. Using the data retrieved from the persistent memory, the one or more IP calls are resynthesized using a device simulator process to simulate connectivity with endpoints that were participating in the one or more IP calls prior to the outage. After resynthesizing, depending on activity detected from devices associated with the one or more IP calls, the one or more IP calls are internally re-stitched/re-establishing (without signaling to endpoints) with the endpoints involved in the one or more IP calls, or the one or more calls are fully re-stitched/re-established by signaling an endpoint that was participating in the one or more IP calls.

Abstract: In one embodiment, a network interruption may be determined to have occurred at an active node of a communication system, wherein the active node may be facilitating a first communication dialog between a first end point and a second end point. In response to the network interruption, a stateful switchover can be initiated between the active node and a standby node of the communication system. A reroute message may be transmitted to the first end point and the second end point, wherein the reroute message can instruct the first end point and the second end point to cease use of the first communication dialog and begin use of a second communication dialog, wherein the second communication dialog may be facilitated by the standby node.

Abstract: In one embodiment, a network interruption may be determined to have occurred at an active node of a communication system, wherein the active node may be facilitating a first communication dialog between a first end point and a second end point. In response to the network interruption, a stateful switchover can be initiated between the active node and a standby node of the communication system. A reroute message may be transmitted to the first end point and the second end point, wherein the reroute message can instruct the first end point and the second end point to cease use of the first communication dialog and begin use of a second communication dialog, wherein the second communication dialog may be facilitated by the standby node.

Abstract: In one embodiment, a clock on a network device is initialized, and then a first timing message is received at the network device from a reference device having a first timestamp indicating when the first timing message was transmitted from the reference device. The network device may then determine and store a one-way delay from the first timestamp to a first time at which the first timing message was received at the network device. In response to restarting the clock, the network device may receive a second timing message from the reference device having a second timestamp indicating when the second timing message was transmitted from the reference device. The network device may then calibrate the clock such that a second time at which the network device received the second timing message is the second timestamp plus the stored one-way delay.

Abstract: A system may generate from a first value, based on rounding information, a first security key that matches a second security key whenever the first value and a second value from which the second security key is generated differ by less than a non-zero predetermined amount. The second security key may be generated from the second value rounded to a multiple of a rounding interval that is nearest to the second value. The rounding information may include a rounding direction indication. The rounding direction indication may indicate the direction in which the second value is rounded to the multiple of the rounding interval nearest to the second value.

Abstract: A system for verifying VoIP call routing information. The system may include an apparatus integrated with a private branch exchange (PBX). The apparatus may store at least one call attribute of a public switched telephone network (PSTN) call initiated to a destination telephone number. The apparatus may verify a destination Voice-over-Internet-Protocol (VoIP) call agent for the destination telephone number based on demonstrated knowledge of the PSTN call. The apparatus may route a new call either over a VoIP network to the destination VoIP call agent or over a circuit switched network based on whether the destination VoIP call agent is verified for the destination telephone number.

Abstract: In one embodiment, an apparatus may receive at least one call attribute of a public switched telephone network (PSTN) call initiated to a destination telephone number. The apparatus may verify a destination Voice-over-Internet-Protocol (VoIP) call agent for the destination telephone number based on demonstrated knowledge of the PSTN call. The apparatus may transmit an indication the destination VoIP call agent is verified for the destination telephone number.

Abstract: In one embodiment, a clock on a network device is initialized, and then a first timing message is received at the network device from a reference device having a first timestamp indicating when the first timing message was transmitted from the reference device. The network device may then determine and store a one-way delay from the first timestamp to a first time at which the first timing message was received at the network device. In response to restarting the clock, the network device may receive a second timing message from the reference device having a second timestamp indicating when the second timing message was transmitted from the reference device. The network device may then calibrate the clock such that a second time at which the network device received the second timing message is the second timestamp plus the stored one-way delay.

Abstract: A system may generate from a first value, based on rounding information, a first security key that matches a second security key whenever the first value and a second value from which the second security key is generated differ by less than a non-zero predetermined amount. The second security key may be generated from the second value rounded to a multiple of a rounding interval that is nearest to the second value. The rounding information may include a rounding direction indication. The rounding direction indication may indicate the direction in which the second value is rounded to the multiple of the rounding interval nearest to the second value.

Abstract: A system for verifying VoIP call routing information. The system may include an apparatus integrated with a private branch exchange (PBX). The apparatus may store at least one call attribute of a public switched telephone network (PSTN) call initiated to a destination telephone number. The apparatus may verify a destination Voice-over-Internet-Protocol (VoIP) call agent for the destination telephone number based on demonstrated knowledge of the PSTN call. The apparatus may route a new call either over a VoIP network to the destination VoIP call agent or over a circuit switched network based on whether the destination VoIP call agent is verified for the destination telephone number.

Abstract: In one embodiment, an apparatus may receive at least one call attribute of a public switched telephone network (PSTN) call initiated to a destination telephone number. The apparatus may verify a destination Voice-over-Internet-Protocol (VoIP) call agent for the destination telephone number based on demonstrated knowledge of the PSTN call. The apparatus may transmit an indication the destination VoIP call agent is verified for the destination telephone number.

Abstract: Disclosed is a radiation detector which includes at least one photoconductive detector and a modulator, which modulates in an on-off manner radiation passing to the photoconductive detector from a radiation source. A bias source is connected to one terminal of the photoconductive detector. A first amplifier is connected to the other terminal of the photoconductive detector, and a second amplifier receives an output of the first amplifier. A first phase detector detects the phase of modulation of the radiation source by the modulator and generates a reference signal relating thereto. A switch in the second amplifier changes, in response to the reference signal generated by the first phase detector, the second amplifier between an inverting state and a non-inverting state as the modulator changes the phase of modulation of the radiation.