Packet loss

About: Packet loss is a research topic. Over the lifetime, 21235 publications have been published within this topic receiving 302453 citations.

Congestion control in computer networks

Abstract: This thesis examines the problem of congestion control in reservationless packet switched wide area data networks We define congestion as the loss of utility to a network user due to high traffic loads and congestion control mechanisms as those that maximize a user's utility at high traffic loads In this thesis, we study mechanisms that act at two time scales: multiple round trip times and less than one round trip time At these time scales, congestion control involves the scheduling discipline at the output trunks of switches and routers, and the flow control protocol at the transport layer of the hosts We initially consider the problem of protecting well-behaved users from congestion caused by ill-behaved users by allocating all users a fair share of the network bandwidth This motivates the design and analysis of the Fair Queueing resource scheduling discipline We then study the efficient implementation of the discipline by doing an average case performance evaluation of several data structures for packet buffering Since a Fair Queueing server maintains logically separate per-conversation queues and approximates a bitwise-round robin server, it partially decouples the service received by incoming traffic streams This allows us to deterministically model a single conversation in a network of Fair Queueing servers Analysis of the model shows that a source can estimate the service rate of the slowest server in the path to its destination (the bottleneck) by sending a pair of back-to-back packets (a packet-pair probe), and measuring the inter-acknowledgement spacing The probe values can be used to control a user's data sending rate We formalize this notion by modeling a conversation as a linear system in a simple control-theoretic approach This is used to synthesize a robust and provably stable flow control protocol The network state, that is, the service rate of the bottleneck, can be estimated from the series of probe values using an estimator based on elementary fuzzy logic Our analysis and performance claims are examined by simulation experiments on a set of eight test scenarios We show that under a wide variety of test conditions, both of our schemes provide users with good performance Thus, these mechanisms should prove useful in future high-speed networks

Energy-Efficient Algorithm for Reliable Routing of Wireless Sensor Networks

Abstract: Quality of service (QoS) routing is one of the critical challenges in wireless sensor networks (WSNs), especially for surveillance systems. Multihop data transmission of WSNs, due to the high packet loss and energy-efficiency, requires reliable links for end-to-end data delivery. Current multipath routing works can provision QoS requirements like end-to-end reliability and delay, but suffer from a significant energy cost. To improve the efficiency of the network with multiconstraints QoS parameters, in this paper we model the problem as a multiconstrained optimal path problem and propose a distributed learning automaton (DLA) based algorithm to preserve it. The proposed approach leverages the advantage of DLA to find the smallest number of nodes to preserve the desired QoS requirements. It takes several QoS routing constraints like end-to-end reliability and delay into account in path selection. We simulate the proposed algorithm, and the obtained results verify the effectiveness of our solution. The results demonstrate that our algorithm has a better performance than current state-of-the-art competitive algorithms in terms of end-to-end delay and energy-efficiency.

MTCP: scalable TCP-like congestion control for reliable multicast

Abstract: We present MTCT, a congestion control scheme for large-scale reliable multicast. Congestion control for reliable multicast is important because of its wide applications in multimedia and collaborative computing, yet nontrivial, because of the potentially large number of receivers involved. Many schemes have been proposed to handle the recovery of lost packets in a scalable manner; but there is little work on the design and implementation of congestion control schemes for reliable multicast. We propose new techniques that can effectively handle instances of congestion occurring simultaneously at various parts of a multicast tree. Our protocol incorporates several novel features: (1) hierarchical congestion status reports that distribute the load of processing feedback from all receivers across the multicast group, (2) the relative time delay (RTD) concept which overcomes the difficulty of estimating round-trip times in tree-based multicast environments, (3) window-based control that prevents the sender from transmitting faster than packets leave the bottleneck link an the multicast path through which the sender's traffic flows, (4) a retransmission window that regulates the flow of repair packets to prevent local recovery from causing congestion, and (5) a selective acknowledgment scheme that prevents independent (i.e., non-congestion-related) packet loss from reducing the sender's transmission rate. We have implemented MTCP both on UDP in SunOS 5.6 and on the simulator ns, and we have conducted extensive Internet experiments and simulation to test the scalability and inter-fairness properties of the protocol. The encouraging results we have obtained support our confidence that TCP-like congestion control for large-scale reliable multicast is within our grasp.

pTunes: runtime parameter adaptation for low-power MAC protocols

Abstract: We present pTunes, a framework for runtime adaptation of low-power MAC protocol parameters. The MAC operating parameters bear great influence on the system performance, yet their optimal choice is a function of the current network state. Based on application requirements expressed as network lifetime, end-to-end latency, and end-to-end reliability, pTunes automatically determines optimized parameter values to adapt to link, topology, and traffic dynamics. To this end, we introduce a flexible modeling approach, separating protocol-dependent from protocol-independent aspects, which facilitates using pTunes with different MAC protocols, and design an efficient system support that integrates smoothly with the application. To demonstrate its effectiveness, we apply pTunes to X-MAC and LPP. In a 44-node testbed, pTunes achieves up to three-fold lifetime gains over static MAC parameters optimized for peak traffic, the latter being current - and almost unavoidable - practice in real deployments. pTunes promptly reacts to changes in traffic load and link quality, reducing packet loss by 80% during periods of controlled wireless interference. Moreover, pTunes helps the routing protocol recover quickly from critical network changes, reducing packet loss by 70% in a scenario where multiple core routing nodes fail.

Traffic engineering with forward fault correction

Abstract: Faults such as link failures and high switch configuration delays can cause heavy congestion and packet loss. Because it takes time to detect and react to faults, these conditions can last long---even tens of seconds. We propose forward fault correction (FFC), a proactive approach to handling faults. FFC spreads network traffic such that freedom from congestion is guaranteed under arbitrary combinations of up to k faults. We show how FFC can be practically realized by compactly encoding the constraints that arise from this large number of possible faults and solving them efficiently using sorting networks. Experiments with data from real networks show that, with negligible loss in overall network throughput, FFC can reduce data loss by a factor of 7--130 in well-provisioned networks, and reduce the loss of high-priority traffic to almost zero in well-utilized networks.