Fast packet switching

About: Fast packet switching is a research topic. Over the lifetime, 5641 publications have been published within this topic receiving 111603 citations.

Delay compensation in packet-switching networked controlled systems

Abstract: In this paper, we consider the problem of stabilizing sufficiently smooth nonlinear time-invariant plants over a network whereby feedback is closed through a limited-bandwidth digital channel. Reliable packet switching networks are explicitly considered, for which both the time between consecutive accesses to each node (MATI) and the delay by which each data packet is received, processed, and fed back to the plant are unknown but bounded. For what concerns networked feedback control, the main difference between a packet-switching and a circuit-switching network with the same bandwidth is that packets can convey larger amounts of feedback data (measurements and control inputs) with much higher latency and jitter than a conventional communication channel. To compensate the unpredictably varying delays in packet switching networked control systems, we propose a model-based strategy that exploits the relatively high payload which can be associated to each packet. A bound on the tolerable delays and access frequency is explicitly provided.

Packet generation systems and methods

Abstract: Disclosed herein are various embodiments of methods, systems, and apparatus for increasing packet generation in a digital communication system. In one exemplary method embodiment, multiple input signals are interpolated, shifted, and aggregated into a composite signal for transmission over a network.

Scheduling with different time intervals

Abstract: The invention describes a method for transmitting data packets over a packet switching network with widely varying link speeds. The switches of the network maintain a common time reference (CTR). Each switch along a route from a source to a destination forwards data packets in periodic time frames (TFs) of a plurality of durations that are predefined using the CTR. The time frame duration can be longer than the time duration required for transmitting a data packet, in which case the exact position of a packet in the time frame is not predetermined. In accordance with the present invention, different time frame durations: TF1, TF2, and so on are used for forwarding over links with different capacities. This invention further describes a method for transmitting and forwarding data packets over a packet switching and shared media networks. The shared media network can be of various types, including but not limited to: IEEE P1394 and Ethernet for desktop computers and room area networks, cable modem head-end (e.g., DOCSIS, IEEE 802.14), wireless base-station (e.g., IEEE 802.11), and Storage Area Network (SAN) (e.g., FC-AL, SSA). The invention further describes a method for interfacing a packet-switched network with real-time streams from various sources, such as circuit-switched telephony network sources. A data packet that is packetized at the gateway is scheduled to be forwarded to the network in a predefined time that is responsive to the common time reference. The invention relates, in particular, to timely forwarding and delivery of data packet between voice over IP (VoIP) gateways. Consequently, the invention provides a routing service between any two VoIP gateways where the end-to-end performance parameters, such as loss, delay and jitter, have deterministic guarantees. Furthermore, the invention enables gateway functions with minimum delay.

Deadlock-Free Packet Switching Networks

Abstract: Deadlock states have been observed in existing computer networks, emphasizing the need for carefully designed flow control procedures (controllers) to avoid deadlocks. Such a deadlock-free controller is readily found if we allow it global information about the overall network state. Generally, this assumption is not realistic, and we must resort to deadlock-free local controllers using only packet and node information. We present here several types of such controllers, we study their relationship and give a proof of their optimality with respect to deadlock-free controllers using the same set of local parameters.

A New Performance Measurement for Voice Transmission in Burst and Packet Switching

Abstract: Voice transmission in burst switching is characterized by the process of talkspurt clipping, while in packet switching, it is characterized by the process of packet delay. In most analyses, the talkspurt clipping has been measured by the clipping probability averaged over all bits, and the packet delay has been measured by the delay performance averaged over all packets. The resulting measures overlook the duration of clipping in a talkspurt and the significant difference of delay in packets arriving at different times. Because of the nature of voice, different effects of these may result in substantially different degrees of voice distortion. This paper studies the worst case performance of both processes. The voice traffic is modeled as a process alternating between overload and underload periods. Statistically, more clipping and delay will be incurred while in the overload period. By worst case we mean that, in burst switching, we measure the worst case of talkspurt clipping duration in an overload period, while in packet switching, we measure the worst case of packet delay in an overload period. Furthermore, a simple closed form equation is derived which gives a very good approximation of the worst case mean packet delay performance. This equation can be more generally applied when the packet service time is to be geometrically distributed or when voice and data are to be integrated. The voice performances in burst switching and packet switching are also compared.