Techniques for testing a networked system using simulated abnormal node failure are disclosed. In some embodiments, a computer system performs operations comprising: repeatedly transmitting simulated requests to a networked system on which a software application is implemented using a plurality of nodes, the networked system being configured to respond to the simulated requests using the plurality of nodes; randomly selecting one or more nodes from the plurality of nodes; terminating the randomly selected one or more nodes; restarting the terminated randomly selected one or more nodes; repeating the randomly selecting one or more nodes, the terminating the randomly selected one or more nodes, and the restarting the terminated randomly selected one or more nodes until each one of the plurality of nodes has been terminated and restarted at least once during the first period of time; and determining response times of the networked system in responding to the simulated requests.

In some examples, a computing device may determine a prediction of a network outage of a network. The computing device may determine a priority of one or more data types expected to be received during the network outage. Further, the computing device may determine a latency category of the one or more data types expected to be received during the network outage. The computing device may store a data transmission rule for the one or more data types at least partially based on the priority and the latency category. The computing device may receive, from one or more data generators, during the network outage, data for transmission to the network. The computing device may transmit at least some of the received data to the network at least partially based on the data transmission rule.

In one embodiment, a network device, including packet processing circuitry, which includes at least one interface configured to receive packets, and packet forwarding circuitry configured to make respective forwarding decisions for respective ones of the packets, wherein the packet processing circuitry is configured to assign sequence numbers to the packets in at least one stage of packet processing, find missing packets in at least one corresponding later stage of the packet processing responsively to checking for missing sequence numbers among the assigned sequence numbers, and report the missing packets.

In one embodiment, a network device, including packet processing circuitry, which includes at least one interface configured to receive packets, and packet forwarding circuitry configured to make respective forwarding decisions for respective ones of the packets, wherein the packet processing circuitry is configured to assign sequence numbers to the packets in at least one stage of packet processing, find missing packets in at least one corresponding later stage of the packet processing responsively to checking for missing sequence numbers among the assigned sequence numbers, and report the missing packets.

Systems and methods for routing trade orders based on exchange latency are disclosed. An example method includes measuring a first latency associated with a first exchange based on a processing time of a first trade order; and routing a second trade order from a trading device to one of the first and a second exchange based on the first latency.

In a transceiver, the accuracy of a packet time stamp can be improved by compensating for errors introduced by processing of the packet. A received packet can be received via multiple lanes. A packet time stamp can be measured using a start of frame delimiter (SFD). A last arriving lane can be used to provide a recovered clock signal. A phase offset between the recovered clock signal and the system clock of the transceiver can be used to adjust the time stamp. A position of the SFD within a data block can be used to adjust the time stamp. A position of the data block within a combined group of data blocks can be used to adjust the time stamp. Also, a serializer-deserializer delay associated with the last arriving lane can be used to adjust the time stamp.

A system includes at least one server that is configured to provide a multi-client network service to a plurality of existing users. When the server receives requests to join the multi-client network service from new users, the server may issue timestamps to each new user, obtain load metric based on the requests or timestamps, and collect the load metric to obtain historical data characterizing a demand in the multi-client network service over time. Further, based on the historical data, the server can predict a future load demand in the multi-client network service and selectively enable to join the multi-client network service by at least one of the plurality of new users based on the future load demand.

A system includes at least one server that is configured to provide a multi-client network service to a plurality of existing users. When the server receives requests to join the multi-client network service from new users, the server may issue timestamps to each new user, obtain load metric based on the requests or timestamps, and collect the load metric to obtain historical data characterizing a demand in the multi-client network service over time. Further, based on the historical data, the server can predict a future load demand in the multi-client network service and selectively enable to join the multi-client network service by at least one of the plurality of new users based on the future load demand.

In one embodiment, a system includes a first data communication device including packet processing circuitry to provide a probe packet including an egress timestamp TS1 indicating a time at which the probe packet egresses the first data communication device, and a network interface to send the probe packet via at least one network connection to a second data communication device, and receive from the second data communication device a response packet including the egress timestamp TS1, wherein the packet processing circuitry is configured to associate with the response packet an ingress timestamp TS2 indicating a time at which the response packet ingresses the first data communication device, and a network metric processor to compute a data latency in the at least one network connection responsively to TS1, TS2, and an indication of an internal latency of the probe packet in the second data communication device.

Described is a method and system for connectivity diagnostics in communication systems. The method comprises: querying a first communication device at a first time and a second time to determine whether a second communication device is connected to the first communication device and to determine a value of an operational parameter at the first and second times; and determining the second communication device disconnected from the first communication device based on detecting the second communication device was connected to the first communication device at both the first time and the second time, and detecting the value of the operational parameter at the second time is inside a range of threshold values. In one embodiment, the method comprises determining a link is unstable for connectivity based on connection duration, number and/or pattern of connection and/or disconnection events, and/or traffic activity during connection and/or disconnection events.