184 results about "Message delay" patented technology

A distributed computing system, having a sufficient number of devices and requiring a sufficiently large number of devices to select any proposal, can maintain synchronization between its constituent devices and respond to client requests with as few as two message delays. A leader can synchronize the devices of the system and establish a safe proposal number for all current and future steps of the system. Devices can then receive client requests directly, treating the request as a proposal having the proposal number determined previously by the leader, and voting for the proposal. If the client receives an indication from a least a quorum of devices, where a quorum can be the minimum number of devices that can be operational at a given time, the client can know that the request was selected. If two or more clients attempt to request different functions at approximately the same time, the system may not select either request, in which case a leader can be requested to determine if any requests may have been selected, and to reestablish a safe proposal number. Systems with fewer devices can also implement the message-delay-reducing algorithm if they can also revert to the standard Paxos algorithm if an insufficient number of devices are operational. Such algorithms can be used to provide an efficient method for determining whether to commit or abort a client transaction.

An automated bandwidth monitoring and control method and system provides for real time, dynamic control of the allocation of bandwidth to selected applications in a communications network based on the selected operational context and the fixed bandwidth available at a network access point. A graphical user interface, using operational terms common to the overall enterprise in which and for which the network is implemented and understandable by an operator, displays the bandwidth allocation strategy, and in substantially real time displays statistics representative of actual bandwidth use at the access point, input functions for modifying the bandwidth allocation strategy in substantially real time and estimated message delay distributions for the applications of the strategy determined based on the actual bandwidth use statistics.

New failure detector mechanisms particularly suitable for use in asynchronous distributed computing systems in which processes may crash and recover, and two crash-recovery consensus mechanisms, one requiring stable storage and the other not requiring it. Both consensus mechanisms tolerate link failures and are particularly efficient in the common runs with no failures or failure detector mistakes. Consensus is achieved in such runs within 3□ time and with 4n messages, where □ is the maximum message delay and n is the number of processes in the system.

A distributed computing system can operate in the face of malicious failures on the part of some of its constituent devices, and provide a minimum of message delays between receiving a client request and providing a response, when each device within the system verifies the sender of any message it receives, and the propriety of the message. The sender can be verified through message authentication schemes or digital signature schemes. The propriety of a message can be verified by receiving a sufficiently large number of equivalent, properly authenticated messages. If the number of malicious devices is represented by the variable “M”, a sufficient number of equivalent, properly authenticated messages to verify that the message is true can be any number of messages greater than M. Furthermore, to verify that a leader device is not maliciously submitting different proposals to different devices using the same proposal number, a quorum of devices can be required to select a proposal, where a quorum is a sufficiently large number of devices such that any other quorum has, as a majority of its devices, non-malicious devices from the first quorum. Therefore, the distributed computing system can operate properly with M number of malicious failures and F number of total failures, and with a minimum of message delays, if the number of constituent devices in the distributed computing system is greater than 3F+2M. Additionally, if the distributed computing system can revert to a more traditional algorithm if too many devices fail or become malicious, it can use a message-delay-reducing algorithm while having as few as 2Q+F+2M+1 constituent devices, where Q is the number of devices that can fail and still allow the system to use a message-delay-reducing algorithm.

An apparatus, system, and method are provided for automatically freeing locked server resources using a timeout value closely related to actual real-time message delays plus a delta value that can be adjusted at a plurality of levels. The levels include default, server, connection, and transaction. The apparatus includes a timer, a communication module, a computation module, and a lock handler. The timer determines a timeout value for communications from a client to a server. The communication module sends an output message to the client and locks a server resource in anticipation of an acknowledgement (ACK) message from the client. The computation module, which calculates an ACK timer, includes a difference between a send time and a current time. If no ACK message has been received from the client and the ACK timer exceeds the timeout value, the lock handler may free the locked server resource.

A distributed computing system can achieve consensus while introducing fewer message delays by using an algorithm that allows the constituent devices to vote on functions received directly from one or more clients. If a conflict occurs, a leader device from among the devices can be selected such that the leader device already knows of the other devices' previous votes, and can determine an appropriate function to propose, using an immediately subsequent proposal number, without performing the first phase of the Paxos algorithm. Alternatively, each device can independently determine, by using the same repeatable mechanism used by a leader device, what function the leader device would propose, and can then vote for that function using the immediately subsequent proposal number. If the devices' votes again result in a conflict, the Paxos algorithm can be used, or additional iterations can be performed prior to resorting to the Paxos algorithm.

The utility model provides a network constrained moving object database-based traffic flow data acquisition and analysis method; wherein, the time and space trace is acquired and stored by means of the technology of network restricted mobile object database, the acquired data is online counted in denomination of atomic driving section and by the technology of time and space statistics and analysis, then a plurality of traffic parameters of the traffic network are acquired on a real-time basis, and the temporal data of the traffic parameter changing is stored. The acquired data reflects the integral time and space trace of the mobile object, simplifies the complexity of the statistics and analysis, enhances the processing efficiency, and provides more sufficient information for data analysis and intensifies the precision of the data processing. Moreover, message delay is eliminated because the process of traffic parameter refreshing can be triggered by updating the positions of the mobile objects on a real-time basis. Compared with the prior traffic flow statistics and analysis method, the utility model has the advantages of high efficiency, high precision and real-time availability..

A conflict tolerant message delay reducing consensus algorithm is presented for operating a distributed computing system. The devices of the distributed computing system can directly receive client requests, and can execute the requests and respond directly to the clients, saving message delays. If there is a conflict, the ultimately selected request can be the request submitted by the client with the highest client identifier. A device can change its vote, and execute a different request, if it is made by a client having a more dominant client identifier. All but one of the clients can also be a device implementing the system. A device that has executed a requested function may no longer submit a request in the same step. Consequently, a request is executed by the system when all devices have executed the request. If one or more devices fails, any fault tolerant consensus algorithm can be used.

The invention discloses a time-triggered based airborne optical network simulation system. The system comprises a configuration input and output module (1), an optical network topology configuration module (2), an optical network message configuration module (3), an optical network generation module (4), an optical network simulation module (5) and a result output display module (6). By simulating the generation of communication tasks and a running process in the airborne optical network, the airborne optical network simulation system provided by the invention solves the technical problem in the existing airborne optical network that time certainty is not provided for messages transmitted in real time in a transmission mechanism. The airborne optical network simulation system provided by the invention can add a Time-Triggered in the airborne optical network, and can make the airborne optical network have certain timeliness and can more efficiently use network bandwidth resource, so as to realize a technical effect that the airborne optical network has time certainty in transmitting message delay.

A system using two algorithms for scheduling packets in a multi-hop network. The objective of the algorithms is to reduce end-to-end message (not packet) transmission delays. Both algorithms schedule packet transmissions based on the length of the original message to which the package belongs. The first algorithm is preemptive and is based on the shortest-message-first principle and the second is based on the shortest-remaining-transmit-time principle. We develop simulation models for analyzing the algorithms. The simulations show that when message sizes vary widely, these algorithms can significantly reduce average end-to-end message delays compared to the First-Come-First-Serve scheduling.

The invention discloses a routing control method based on big-scale WSN (wireless sensor network) emergency monitoring, which comprises four steps of building a network model, initializing a network, electing a cluster and transmitting data, wherein in the data transmission process, a cluster node selects a trunking mode of one hop or multiple hops to send effective monitoring data back to a gateway node according to the fact whether the gateway node is in a self 'neighbor node log sheet'; and in the trunking mode of multiple hops, the current node selects different algorithms to find a next-hop route node according to the self residual energy situation. The routing control method has the outstanding effects that the cluster node and the gateway node are communicated in the trunking mode of one hop or multiple hops to avoid excessive energy loss caused by long-distance transmission. According to the mechanisms of a cluster node and relay node election method, self-adaption power regulation, message delay forwarding control and the like, network energy consumption is saved and balanced so as to delay the time of the first dead node and improve the network performance.

Methods and apparatus for a Secure Time Communication System (10) are disclosed. One embodiment of the invention provides secure and non-interactive communication of clock information over an unsecured communications channel. This communication provides perfect forward secrecy, while detecting and blocking message spoofing, message replay, denial of service and cryptographic performance attacks. This mechanism also bounds the effect of message delay manipulation. The mechanism consists of two components, a filtered time encryptor (16) and a filtered time decryptor (28). The filtered time encryptor (16) produces a message in two parts; a time token followed by an encrypted message body. The time token is used as a filter to detect most attacks and to determine the message key.

The invention discloses a short message delay reminding terminal and a method, which belong to the communication field. The terminal comprises a main control module, a memory module, a setup module and a reminding module, wherein the main control module is used for receiving operation order of the user; the memory module is used for storing the short message received by the cell phone and for managing the delay reminding time; the setup module is used for setting the delay reminding of the short message; and the reminding module is used for reminding the user to check and accept the short message after the delay time is ended. The method comprises the following steps that: user can set up the short message delay reminding for particular phone number and/or strange phone number; a delay reminding time is set up on the cell phone for the short message with the delay reminding; and when the reminding time is up, the cell phone reminds the user to check and accept the short message. By utilizing the short message delay reminding terminal, not only the disturbing of the strange short message can be avoided within a given period of time, but also the useful short message can be avoided to miss.

The invention provides a business locking and unlocking method and device which are applied to the technical field of data clusters. The business locking and unlocking method includes that: a local lock manager (LLM) receives a locking or unlocking request of a business; the LLM places the locking or unlocking request of the business into a batch message packet when determining that the locking or unlocking request of the business cannot be met locally, wherein the batch message packet is used for storing a plurality of locking or unlocking requests; and the LLM transmits the batch message packet to a general lock manger (GLM) when judging that batch messages meet batch conditions, so that the GLM can process the locking or unlocking request in the batch message packet conveniently. By adopting the business locking and unlocking method and device, the quantity of the locking or unlocking requests transmitted to the GLM by the LLM in a short time can be reduced, pressure of a channel between the LLM and the GLM is reduced, message delay is reduced, and linear scalability of the database clusters is improved.

The invention discloses a smart home communication system based on dual-mode communication. A Lora communication module is added in a gateway, and a Lora communication module is also added in a terminal module. Based on the above, the communication modes of the two modes are merged. The communication signal strength of the Lora network is set to the lowest signal strength to meet the communicationstability, so as to avoid interference with the zigbee network system and the physically adjacent lora communication system. Meanwhile, the smart home communication system preferentially uses the zigbee link for communication. When the zigbee link fails, the LoRa link is used for re-delivery to ensure reliable communication. When the gateway broadcasts a message, the message is sent by the LoRa link, and the message delay is short to avoid the zigbee broadcast storm. The system has the beneficial effects that the smart home communication system can be stable and reliable, the device respondsin time, and the requirements of low power consumption of the device can be met.

The invention discloses a centralized internet of vehicle MAC layer combination and collision predicting and preventing method, belonging to the field of VANET. The method permits reuse of a node timeslot beyond two hops, thereby making the timeslot resource more efficient. First, a road side unit (RSU) can access an idle timeslot set in an RSU timeslot broadcast node in each timeslot period, and a new node selects a timeslot to access randomly according to the timeslot set; then the RSU acquires a position, a speed and timeslot use condition of a vehicle in a range through a relay node, so as to predict the possibility that combination and collision occur; and finally, the RSU adjusts timeslot allocation and broadcasts an adjustment result, so as to prevent combination and collision effectively. In the method, timeslot reuse and assistance of RSU help lower the possibility of combination and collision, so as to shorten message delay of the MAC layer and increase throughput. The method can be used as an MAC layer protocol for sending a broadcast message by a node in the VANET.

The invention discloses a method and system for realizing a delay message queue, and the method comprises the steps that a client module transmits a message to a server module, and the server module writes the message into a relational database for storage; the server module judges that the expiration time of the message is greater than the time of the current server, and generates a delay messagerecord; the server module writes the delay message record into a delay message queue in a memory database, and periodically polls the delay message queue; the client module pulls a delay message record to the server module, and the server module checks the delay message queue, reads the message content in the relational database and feeds back the message content to the client module; and the client module receives the message content, sends ACK to the server module, and displays that the message is successfully received. According to the method, an extension strategy is adopted, various service scenes needing message delay are supported, functions of an existing message queue system are fully utilized to achieve zero invasion, and risks caused by modification of an original message queuesystem are avoided.

Improved protocols for wireless networking are disclosed. At low/zero marginal cost, embodiments enable increased throughput and reduced delays at high traffic density, while greatly reducing message collisions and ensuring that each user is able to transmit in order. By providing a sequencing advantage to nodes that have already been delayed, embodiments can eliminate the “blocked node” problem in which some nodes are suppressed indefinitely while other nodes are allowed to dominate a communication channel with multiple transmissions. As the wireless traffic density soars in the coming years, embodiments can improve system utility while enhancing user satisfaction by providing higher message success rates, reducing user frustration, minimizing message delays and message collisions, and eliminating node blocking. An array of embodiments can be implemented on existing and planned equipment with appropriate programming. And of vital importance in emergencies, the likelihood of a blocked 911 call can be significantly reduced.

Asynchronous messages are used to prefetch and/or relinquish tokens used in providing locking of shared resources. A message is sent to prefetch one or more tokens, and prior to receiving a reply for the message, another message (e.g., an acquire) is sent for at least one of those tokens. Similarly, a message is sent indicating a voluntary relinquish of one or more tokens and without having acknowledgment that the relinquish request was processed, a further message (e.g., an acquire) is sent for at least one of the tokens. Multiple tokens may be acquired and/or relinquished in a single message to the token server. This reduces message delays and overall message traffic.

This method securely transmits data from a secure control system [110] located on an isolated computer network [100] to a separate computer [210] outside the isolated control network [100]. The method includes several features designed to minimize the risk of outside cyber attack on the control system [110] while ensuring that the data is transmitted correctly and promptly. The system uses a non-routable unidirectional physical data link [300]. Messages [400] are redundantly transmitted to computer [210] without acknowledgement along with checksums [430,450]. The checksum information is used to validate that the message header [420] and the message data [440] have been received correctly. Redundant information contained in repeated message data blocks [440] is discarded after the transmitted message [400] is correctly received and decoded. An ordered transmission sequence is used to minimize the message delay if an individual message [400] was not received correctly on its first transmission.