Packet loss

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

Reliable communication over unreliable channels

Abstract: Layered communication protocols frequently implement a FIFO message fiacility cm top of an unrehable non-FIFO serwce such as that provided hy a packet-swltchmg network. This paper investigates the possibdity of Implementing a reliable message layer on top of an underlying layer that can low packets and deliver them out of order, with the addltlonzd restriction that the implementatmn uses only a fixed fimte number of different packets. A new formalism is presented to spcclfy communication layers and their properties, the notion of their implementation by 1/0 automata. and the properties of such implementations. An 1/0 automaton that Implements a rellable layer over an unreliable layer is presented In this implementation, tbe number ot packets needed to deliver each succeeding message increases permanently as additional packet-loss and reordering faults occur. A proof is gwen that no protocol can avoid such performance degradatmn.

Network architecture and methods for transparent on-line cross-sessional encoding and transport of network communications data

Abstract: A computer implemented method and system for transferring data packets includes intercepting a stream of data packets (402) at the connectionless network layer from a client or server, encoding and encapsulating the data packets (404), transmitting the encoded data packets (406), decoding and decapsulating the data packets (410), and injecting the decoded and decapsulated data packets into the connectionless network layer at a client or server (412). The encoding of the packets is based on detecting repetitions that could exist anywhere in the data stream. The repetitions are not necessarily within a single packet but could occur across multiple packets and multiple sessions. One of the encoding algorithms includes includes comparing the payloads of packets with identical signatures and transmitting the full packet only when the payload had not previously been sent.

Packet loss resilient transmission of MPEG video over the Internet

Abstract: A method is proposed to protect MPEG video quality from packet loss for real-time transmission over the Internet. Because MPEG uses inter-frame coding, relatively small packet loss rates in IP transmission can dramatically reduce the quality of the received MPEG video. In the proposed high-priority protection (HiPP) method, the MPEG video stream is split into high- and low-priority partitions, using a technique similar to MPEG-2 data partitioning. Overhead resilient data for the MPEG video stream is created by applying forward error correction coding to only the high-priority portion of the video stream. The high- and low-priority data, and resilient data, are sent over a single channel, using a packetization method that maximizes resistance to burst losses, while minimizing delay and overhead. Because the proposed method has low delay and does not require re-transmission, it is well suited for interactive and multicast applications. Simulations were performed comparing the improvement in video quality using the HiPP method, using experimental Internet packet loss traces with loss rates in the range of 0–8.5%. Overhead resiliency data rates of 0%, 12.5%, 25%, and 37.5% were studied, with different compositions of the overhead data for the 25% and 37.5% overhead rates, in an attempt to find the “best” composition of the overhead data. In the presence of packet loss, the received video quality, as measured by PSNR and the Negsob measure, was significantly improved when the HiPP method was applied.

Methods and apparatus for determining communication link quality

Abstract: Methods and apparatus for determining the quality of a communication link transmitting a specified packet type are disclosed. The methodology includes configuring first packets, which share transmission characteristics with a specific packet type, such as a Voice over IP packet, such that the first packets experience similar communication link treatment as the specific packet type. The first packets are then transmitted over the communication link to a quality monitoring server located near a termination equipment of the particular communication link. Second packets, which are transmitted by the server in response to the first packets, are received and evaluated to determine the quality of the communication link based on characteristics of the second packets. Corresponding apparatus are also disclosed.

Monitoring quality of service in a packet-based network

Abstract: A method arid apparatus for generating probe packets for network measurements, in which a first probe packet is generated by normal routing through a protocol stack, following which a packet processor determines, from the routing information added by the stack, a template for generating a series of packets. Based on parameters supplied to the packet processor, a complete stream of probe packets for measuring network performance to a remote endpoint can be generated without further use of the protocol stack. Also provided is a receive-end apparatus and method which determines, by processing a single received probe packet, the format necessary to loop back further packets received in a stream from the same source, and generates the return headers allowing each packet in the stream to be looped back without further involving the protocol stack.