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.

Graceful degradation over packet erasure channels through forward error correction

Abstract: We present an algorithm that assigns unequal amounts of forward error correction to progressive data so as to provide graceful degradation as packet losses increase. We use the SPIHT coder to compress images in this work, but our algorithm can protect any progressive compression scheme. The algorithm can also use almost any function as a model of packet loss conditions. We find that for an exponential packet loss model with a mean of 20% and a total rate of 0.2 bpp, good image quality can be obtained, even when 40% of transmitted packets are lost.

Method and apparatus for cut-through data packet transfer in a bridge device

Abstract: A technique for reducing latencies in bridge operation, by facilitating cut-through transmission of a receive data packet while the packet is still being received, but without the need for starting or ending delimiters,or packet lengths, in the packet data. The technique can be applied to packets inbound from a network, packets outbound to a network, or packets being looped back to a client to which the bridge is connected. In the technique of the invention, each received packet is stored in a buffer memory and a count is maintained of the number of bits in the received packet. A transmit operation is started as soon as possible, preferably while the packet is still being received, and bytes are retrieved from the buffer memory for transmission. The transmit operation is terminated when a transmit byte count reaches the packet length as determined by the receive byte count. For cut-through operations, the transmit operation is started without knowledge of the packet length, but the packet length is made available to the transmit operation upon completion of the receive operation. For store-and-forward operations, the packet length is stored with the packet in the buffer memory, and retrieved for use in the transmit operation.

Packet Transmission Control Device and Packet Transmission Control Method

Abstract: The present invention relates to a packet transmission control device which controls transmission of packets to a plurality of mobile stations. A scheduling unit of the packet transmission control device according to the present invention is configured to schedule the packets to each of the plurality of mobile stations, based on an average transmission rate, a minimum guaranteed transmission rate, a scheduling frequency and capability information.

Effect of speedup in nonblocking packet switch

Abstract: The nonblocking packet switch under consideration has N inputs and N outputs and operates L times as fast as the input and output trunks. The effect of speedup (L) on packet loss probability and average transmission delay in the case of an arbitrary number L, such that 1 >

The Design and Use of Hazard-Free Switching Networks

Abstract: When combinational switching networks of relay contacts or of electronic gate elements are analyzed or synthesized, the network components are usually idealized in such a way that they may be adequately described by the Boolean algebra. I t is usually postulated [1] that, at all times, all the normally open (or normally closed) contacts on a given relay open and close in synchronism with each other, and that each normally open contact is open (closed) when the normally closed contacts are closed (open), and vice versa. Similarly in a network of electronic gate elements it is usually postulated [2] that an input variable can affect the network output with no intervening time lag. These assumptions, when put to use in synthesis procedures, lead to networks which behave correctly for steady-state situations but which may not for transient conditions (during which a network input variable is changing from one of its binary states to the other). When combinational networks which do not behave ideally (in a sense to be considered below) during changes of input state are incorporated into larger switching networks which have sequential action (that is, which act as if they had memories) a hazard [3] exists and the sequential circuit may not operate as it was meant to by the designer. The significance of a network hazard can be substantially reduced and sometimes eliminated by \"smoothing\" of the network output [4]. In a relay circuit, for example, the contact networks are used to control relays which in turn contribute contacts to the various other contact networks. If the response time of a given relay is increased so as to increase its smoothing action, the effect of a hazard in its controlling network may be eliminated. But now contacts from the given relay which appear in other networks of the circuit may behave even less ideally than they did originally, thus creating new hazards in the other networks. Moreover, in both relay and electronic circuits, the stratagem of smoothing at critical points in the circuit will always increase the reaction time of the circuit. In most applications this is undesirable. This paper suggests a method for the elimination of hazards without resort to signal smoothing. It is shown here that it is always possible to synthesize a combinational switching network which behaves ideally even though its individual components do not. The technique proposed here does not involve the use of a new switching algebra. The terminal behavior of the resulting hazard4ree net-