3478 results about "Network congestion" patented technology

A multicast repair tree is established, the repair tree having one sender station and a plurality of repair head stations. A repair head station has an affiliated group of member stations. A repair head station retransmits a lost message to its affiliated group of member stations upon receipt from a member station of a NACK message indicating that the selected message was not received. Acknowledgment windows (ACK windows) are established in a member station for transmission of ACK or NACK message by the member station. A number of messages transmitted by the sender station during a transmission window is established. Also a same size of ACK window is established in the receiving stations, with a slot in the ACK window corresponding to each message transmitted by the repair head station. Each receiving station is assigned a slot in the ACK window during which time that receiving station transmits its ACK or NACK messages. Thus the ACK window slots assigned to receiver stations for transmission of ACK/NACK windows are staggered so that different receiver stations transmit their ACKNACK messages at different times. The slot for a particular receiver station to use may be assigned by a random process.

One embodiment of the present invention provides a system that avoids network congestion. During operation, the system can detect an onset of congestion in a first queue at a first node. Next, the first node can generate a first control-message, wherein the first control-message contains a congestion-point identifier which is associated with the first queue. The first node can then send the first control-message to a second node, which can cause the second node to delay sending a second message to the first node, wherein the second message is expected to be routed through the first queue at the first node. Next, the second node may propagate the control-message to a third node which may cause the third node to delay sending a third message to the second node, wherein the third message is expected to be routed through the first queue at the first node.

A new Fast Recovery Plus (FR+) mechanism, and associated method, for wireless and/or mobile network applications to control data flow and avoid network congestion in a TCP/IP packet-switched network.

Methods and apparatus for dynamically adapting the degree of compression used in compressing data based upon the type of contents contained within a packet are disclosed. According to one aspect of the present invention, an apparatus that forwards data across a digital communications network includes a compression switch, a compression system, and an output interface. The compression switch receives the data, determines a content type associated with the data by examining the data, and assigns a compression level to the data in response to the determined content type. The compression system is arranged to compress the data based upon the compression level, while the output interface forwards the compressed data across the network. In one embodiment, the apparatus also includes a network congestion estimator that determines a level of network congestion.

The present invention relates to a method and network for controlling congestion in a packet-switched network, comprising traffic sources, traffic destinations and network nodes, wherein a packet queue length in a network node is determined and a congestion notification is transmitted back towards the source address of an incoming data packet received at the network node, if the detected packet queue length exceeds a predetermined threshold. Then, congestion control is performed at a predetermined intermediate network node in response to the receipt of the congestion notification. Thereby, burts of source traffic can be constrained and unnecessary packet losses can be avoided already at an intermediate access node and within the network. The congestion notification message generated due to an incipient congestion is immediately routed back according to its source address. As a result, control delay time is shortened, such that buffer size requirements and number of congestion notification messages are reduced.

The present invention provides a multi-service queuing method and apparatus that provides exhaustive arbitration, load balancing, and support for rapid port failover. Routers and switches according to the present invention can instantaneously direct the flow of traffic to another port should there be a failure on a link, efficiently handle multicast traffic and provide multiple service classes. The fabric interface interfaces the switch fabric with the ingress and egress functions provided at a network node and provides virtual input and output queuing with backpressure feedback, redundancy for high availability applications, and packet segmentation and reassembly into variable length cells. The user configures fixed and variable-length cells. Virtual input and output queues are coupled to a switch fabric. Statistics regarding the virtual input and output queues are collected and packet queuing for the virtual input and output queues is controlled using the collected statistic to provide congestion control for the virtual input and output queues and the switch fabric.

A new concept of soft quality-of-service (soft-QoS) is developed that bridges the gap between the efficient provision of network-level QoS and the requirements of multimedia applications. Soft-QoS is defined by a satisfaction index (a number that rates users' perceptual quality) and a softness profile (a function that captures the robustness of multimedia applications to network congestion). Another aspect of this invention is a bandwidth allocation scheme for multimedia applications with soft-QoS requirements is presented. The implementation of the bandwidth allocation scheme on a network element realizes a soft-QoS controller. The controller uses the connections' softness profiles to compute a bandwidth allocation that maximizes the minimum satisfaction index of active connections.

A method and system for Mobile Internet Protocol (IP) device redundancy. As mobile devices roam away from a home network and change a connective status, mobility binding records are sent to a multicast network address on the home network. The multicast network address multicasts the mobility binding records to other active Mobile IP home agent control nodes, standby home agent control nodes and standby home agents on the home network. The method and system allows standby home agent control nodes or standby home agents to be transparently switched for active home agent control nodes or active home agents that fail without downloading or uploading large numbers of mobility binding records after a failure. The method and system may also help reduce failed calls (e.g., data sessions including Voice over IP (VoIP), H.323, etc.), network congestion and improve user satisfaction in Mobile IP systems.

A system and process for controlling the coding bit rate of streaming media data is presented where a server streams data that exhibits one of a number of coding bit rates supported by the server. Initially, the server chooses the coding bit rate. However, after this startup period, the client provides coding bit rate requests. The server transmits the streaming media data at the most appropriate supported coding bit rate closest to the rate requested. The coding bit rates requested are those estimated to provide a high quality playback of the streaming data while still keeping a decoder buffer of the client filled to a desired level. A leaky bucket model is incorporated so that the changes in buffer duration due to natural variation in the instantaneous coding bit rate are not mistaken for changes in buffer duration due to network congestion.

A scalable video transmission scheme is provided in which client interaction and video content itself are taken into consideration during transmission. Methods and arrangements are provided to prioritize/classify different types of information according to their importance and to packetize or otherwise arrange the prioritized information in a manner such that lower priority information may be dropped during transmission. Thus, when network congestion occurs or there is not enough network bandwidth to transmit all of the prioritized information about an object, some (e.g., lower priority) information may be dropped at the server or at an intermediate network node to reduce the bit rate. Thus, when the server transmits multiple video objects over a channel of limited bandwidth capacity, the bit rate allocated to each object can be adjusted according to several factors, such as, e.g., information importance and client interaction.

Relay units (1002-1-1002-n) terminate a plurality of transport layer connections from terminals in a transport layer and relay each of these connections to other transport layer connections (relay connections). A transmission rate control unit (1003) determines the total transmission rate of the relay connections according to the number of connections that are being relayed and network congestion conditions such that a desired effective rate is obtained, and moreover, allots the total transmission rate as transmission rates to each of relay units (1002-1-1002-n) in accordance with the results of the analysis of information of the applications being carried on the transport layer connections during relay.

One embodiment of the present invention provides a system that facilitates congestion management in a Fibre Channel (FC) network. During operation, the system determines a threshold data rate on an outgoing link coupled to an FC switch. The system further determines the number of sources that send data to the outgoing link and an aggregate arrival rate of data for the outgoing link. Next, the system determines an injection data rate for a respective source based on the threshold data rate on the outgoing link, the number of sources transmitting data to the outgoing link, and the aggregate arrival data rate for the outgoing link. Subsequently, the system communicates the injection data rate to the source, thereby allowing the source to throttle its data injection in the FC network to prevent network congestion.

Methods and apparatus are provided for controlling congestion in a network such as a fiber channel network. Techniques are provided for detecting congestion at a shared resource such as a network node. When a controller sends data to a shared resource, the delay between sending the data and receiving a credit is measured. If the delay is significant, it is assumed that the path towards the destination associated with the data is congested and subsequent traffic from the port associated with the data is blocked.

A system and method for providing quality of service (QoS) service over a mobile IP network with dynamic domains, multiple or distributed QoS managers per domain and/or with network congestion feedback being used to establish an estimated total domain bandwidth which is used for regulating access to a domain.

A system designed for increasing network communication speed for users, while lowering network congestion for content owners and ISPs. The system employs network elements including an acceleration server, clients, agents, and peers, where communication requests generated by applications are intercepted by the client on the same machine. The IP address of the server in the communication request is transmitted to the acceleration server, which provides a list of agents to use for this IP address. The communication request is sent to the agents. One or more of the agents respond with a list of peers that have previously seen some or all of the content which is the response to this request (after checking whether this data is still valid). The client then downloads the data from these peers in parts and in parallel, thereby speeding up the Web transfer, releasing congestion from the Web by fetching the information from multiple sources, and relieving traffic from Web servers by offloading the data transfers from them to nearby peers.

An admission controller and its method of operation for controlling admission of data flows into an aggregate data flow are described. Admitted data flows are aggregated into an aggregate data flow for transmission by a router, for example, over a data network. The aggregate data flow typically follows a pre-established path through the network; for example a multi-protocol label switched (MPLS) path. The path has minimum and maximum bandwidth limits assigned to it. The admission controller controls admission of new data flows into the aggregate data flow by granting or denying new session requests for the new data flows. Congestion notifications received from the network and bandwidth limits of the path are considered in determining whether to grant or deny a new session request. In this way, the admission controller provides elastic sharing of network bandwidth among data flows without exacerbating network congestion and while remaining within the path's bandwidth limits. The data flows may include transaction oriented traffic.

The invention herein described consists of an algorithm, which performs an end-to-end estimation of the bandwidth available in an end-to-end connection established between a server and a client via a packet switching network such as the Internet Protocol Network (IP). This algorithm is used to properly regulate the input rate at the send side. Typical applications are delivering best effort traffic over TCP, or audio and video traffic over RTP/UDP. The invention is particularly effective over wireless Internet and can be used in a content delivery system to dynamically choose the best server between a set of servers to satisfy the request of a client, or to select the best route in a content deliver or global hosting system.

A network system for actively controlling congestion to optimize throughput is provided. The network system includes a sending host which is configured to send packet traffic at a set rate. The network system also includes a sending switch for receiving the packet traffic. The sending switch includes an input buffer for receiving the packet traffic at the set rate where the input buffer is actively monitored to ascertain a capacity level. The sending switch also includes code for setting a probability factor that is correlated to the capacity level where the probability factor increases as the capacity level increases and decreases as the capacity level decreases. The sending switch also has code for randomly generating a value where the value is indicative of whether packets being sent by the sending switch are to be marked with a congestion indicator. The sending switch also includes transmit code that forwards the packet traffic out of the sending switch where the packet traffic includes one of marked packets and unmarked packets. The network system also has a receiving end which is the recipient of the packet traffic and also generates acknowledgment packets back to the sending host where the acknowledgment packets are marked with the congestion indicator when receiving marked packets and are not marked with the congestion indicator when receiving unmarked packets. In another example, the sending host is configured to monitor the acknowledgment packets and to adjust the set rate based on whether the acknowledgment packets are marked with the congestion indicator. In a further example, the set rate is decreased every time one of the marked packets is detected and increased when no marked packets are detected per round trip time (PRTT).

Methods and apparatus are provided for controlling congestion in a network such as a fibre channel network. Techniques are provided for characterizing traffic flow at a congested network node. The congested network node can generate various instructions such as quench messages to control traffic flow towards the congested network node. The quench messages can optionally include information about the characteristics of the congestion. The instructions are distributed to other nodes in the network. The other network nodes can interpret the instructions and control traffic flow towards the congested node.

A queue length measurement device that is comprised of a number of queues that are capable of holding data cells. A differential counter is coupled to each queue. The counter is incremented when a cell is written into the queue and decremented when a cell is read from the queue. An interval measurement device, coupled to the differential counter, generates a pulse to reset the counter at fixed intervals equivalent to n cells time (where n is the maximum number of cells the queue counter can measure). A multiplexer is coupled to the multiple differential counters. A transfer control circuit coupled to the interval measurement device selects the appropriate queue measurement to be output from the multiplexer to the other switch elements. A system and methodology provide for queue flow statistics and closed loop control of cell flow into the queue. A congestion control system is provided comprising a queue (having an input and an output, and capable of storing and outputting a plurality of data cells), an input processor (for coupling a plurality of data cells to the queue input), an output processor, an interval measurement device (generating a pulse at predetermined intervals), and differential queue length generation logic. The output processor, couples to the queue output, for receiving a plurality of data cells from the queue, which generates a queue change in size signal in response to determining for each of the predefined intervals of the difference between a present and a previous queue length.