Showing papers on "Handshake published in 1999"

Method and apparatus for establishing a secure connection over a one-way data path

Abstract: Improved techniques for facilitating secure data transfer over one-way data channels or narrowband channels are disclosed Often, these channels are wireless channels provided by wireless data networks The techniques enable cryptographic handshake operations for a one-way data channel to be performed over a companion two-way data channel so that the one-way data channel is able to effectively satisfy security protocols that require two-way communications for the cryptographic handshake operations Once the cryptographic handshake operations are complete, data can be transmitted over the one-way data channel in a secure manner Additionally, the techniques also enable the cryptographic handshake operations to be performed more rapidly because the two-way channel is typically a wideband channel In which case, the use of a wideband channel instead of a narrowband channel for the cryptographic handshake operations results in latency reductions, regardless of whether the narrowband channel is a one-way channel or a two-way channel

Reversing the collision-avoidance handshake in wireless networks

Abstract: Many medium-access control (MAC) protocols for wireless networks proposed or implemented to date are based on collisionavoidance handshakes between sender and receiver. In the vast majority of these protocols, including the IEEE 802.11 standard, the handshake is sender initiated, in that the sender asks the receiver for permission to transmit using a short control packet, and transmits only after the receiver sends a short clear-to-send notification. We analyze the effect of reversing the collision-avoidance handshake, making it receiver initiated and compare the performance of a number of these receiver-initiated protocols with the performance of protocols based on sender-initiated collision avoidance. The receiver-initiated protocols we present make use of carrier sensing, and are therefore applicable to either baseband or slow frequencyhopping radios in which an entire packet can be sent within the same frequency hop (which is the case of FHSS commercial radios that support IEEE 802.11). It is shown that the best-performing MAC protocol based on receiver-initiated or sender-initiated collision avoidance is one in which a node with data to send transmits a dual-purpose small control packet inviting a given neighbor to transmit and asking the same neighbor for permission to transmit.

Method, system and computer program product for physical link layer handshake protocol analysis

Abstract: A method, system and computer program product for analyzing link failure in a network is described, wherein a protocol analyzer captures handshake protocol frames exchanged by two nodes attempting to establish a physical link. The captured handshake protocol frames ordered sets are displayed to the user in a merged, time-ordered list, and the information contained in the frames is decoded and displayed. If an attempt to establish a link fails, the symptoms of the failure and a possible diagnosis are identified and displayed. The user is thereby provided with a complete, understandable picture of the events leading up to the link failure, and with symptoms and possible cause of the link failure.

Hula: An Efficient Protocol for Reliable Delivery of Messages

Abstract: We present a new protocol for reliable delivery of messages over a network that might lose, duplicate, reorder, or arbitrarily delay packets It is the first protocol that guarantees exactly-once and ordered delivery on a connection while avoiding precursory handshakes Avoiding handshakes reduces the overhead for sending small, intermittent messages as in remote procedure calls and protocols like HTTP Like other practical protocols, it permits discarding information for idle connections The protocol works by combining existing handshakebased and time-based protocols It uses loosely synchronized clocks to avoid handshakes A handshake is executed only upon an unexpectedly long packet delay or clock skew Thus, unexpected conditions degrade performance but do not compromise reliability The resultant protocol has the reliability of handshake-based protocols and the efficiency of time-based protocols

Use of a soundcard in teaching audio frequency and analog modem communications

Abstract: Sound cards have become standard features of personal computers in the home, office and classroom. This paper demonstrates the usefulness of these inexpensive devices in the teaching of some of the basic and not so basic concepts of communications. These devices can be very effective in the explanation of amplitude, frequency and frequency multiplexed circuits, as well as modem handshake standards.

On Handshake Protocols

Abstract: A frequently recurring theme in the area of communication is the transmission of information from one place to another while there is no buffering facility in between. Such situations, for instance, occur in electronic circuits where wires must carry signals from one end to the other. The problem also pops up when synchronous communication has to be implemented by asynchronous means. The algorithms that take care of such a “bufferless” information transmission are known as handshake protocols, and they are at the heart of the (physical) realization of communication and synchronization between otherwise autonomous computer installations. Also, they are nowadays beneficially used as a starting point for the construction of asynchronous circuitry [Mar96].