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Packetized-voice/data integrated transmission on a token passing ring local area network
This paper investigates the performance of a token passing ring network with packetized-voice/data mixed traffic through extensive simulations. Both data and voice users are modeled in the simulations. Data users produce bursty traffic. Voice traffic is modeled as having alternating talkspurts and silences, with generation of voice packets at a constant rate during talkspurts and no packet generation during silence periods.The network performance measures obtained include: the distribution of transmission delays for voice packets, the average transmission delay and loss probabilities for voice packets, the number of voice users allowed on a network while satisfying the real-time constraints of speech, and the average transmission delay for data packets.Token passing ring local area networks are shown to effectively handle both voice and data traffic. The effects of system parameters (e.g., voice packet length, talkspurt/silence lengths, data traffic intensity, and limited versus exhaustive service disciplines) on network performance are discussed
Synchronization of a WDM Packet-Switched Slotted Ring
In this paper, we present two different strategies of
slot synchronization in wavelength-division-multiplexing (WDM)
packet-switched slotted-ring networks. Emphasis is given to the
architecture behind the WDM Optical Network Demonstrator
over Rings (WONDER) project, which is based on tunable
transmitters and fixed receivers. The WONDER experimental
prototype is currently being developed at the laboratories
of Politecnico di Torino. In the former strategy, a slotsynchronization
signal is transmitted by the master station on a
dedicated control wavelength; in the latter, slave nodes achieve
slot synchronization aligning on data packets that are received
from the master. The performance of both synchronization strategies,
particularly in terms of packet-collision probability, was
evaluated by simulation. The technique based on transmitting a
timing signal on a dedicated control wavelength achieves better
performance, although it is more expensive due to the need for an
additional wavelength. However, the technique based on aligning
data packets that are received from the master, despite attaining
lower timing stability, still deserves further study, particularly
if limiting the number of wavelengths and receivers is a major
requirement. Some experimental results, which were measured on
the WONDER prototype, are also shown. Measurement results,
together with theoretical findings, demonstrate the good synchronization
performance of the prototype
AIRNET: A real-time comunications network for aircraft
A real-time local area network was developed for use on aircraft and space vehicles. It uses token ring technology to provide high throughput, low latency, and high reliability. The system was implemented on PCs and PC/ATs operating on PCbus, and on Intel 8086/186/286/386s operating on Multibus. A standard IEEE 802.2 logical link control interface was provided to (optional) upper layer software; this permits the controls designer to utilize standard communications protocols (e.g., ISO, TCP/IP) if time permits, or to utilize a very fast link level protocol directly if speed is critical. Both unacknowledged datagram and reliable virtual circuit services are supported. A station operating an 8 MHz Intel 286 as a host can generate a sustained load of 1.8 megabits per second per station, and a 100-byte message can be delivered from the transmitter's user memory to the receiver's user memory, including all operating system and network overhead, in under 4 milliseconds
Performance modelling of the Cambridge Fast Ring protocol
The Cambridge Fast Ring is high-speed slotted ring. The features that make it suitable for use at very large transmission rates are the synchronous transmission, the simplicity of the medium-access-control protocol, and the possibility of immediate retransmission of erroneous packets. A novel analytical model of the Cambridge Fast Ring with normal slots is presented. The model is shown to be accurate and usable over wide range of parameters. A performance analysis based on this model is presented
Spacelab system analysis: A study of the Marshall Avionics System Testbed (MAST)
An analysis of the Marshall Avionics Systems Testbed (MAST) communications requirements is presented. The average offered load for typical nodes is estimated. Suitable local area networks are determined
Data communication network at the ASRM facility
The main objective of the report is to present the overall communication network structure for the Advanced Solid Rocket Motor (ASRM) facility being built at Yellow Creek near Iuka, Mississippi. This report is compiled using information received from NASA/MSFC, LMSC, AAD, and RUST Inc. As per the information gathered, the overall network structure will have one logical FDDI ring acting as a backbone for the whole complex. The buildings will be grouped into two categories viz. manufacturing critical and manufacturing non-critical. The manufacturing critical buildings will be connected via FDDI to the Operational Information System (OIS) in the main computing center in B 1000. The manufacturing non-critical buildings will be connected by 10BASE-FL to the Business Information System (BIS) in the main computing center. The workcells will be connected to the Area Supervisory Computers (ASCs) through the nearest manufacturing critical hub and one of the OIS hubs. The network structure described in this report will be the basis for simulations to be carried out next year. The Comdisco's Block Oriented Network Simulator (BONeS) will be used for the network simulation. The main aim of the simulations will be to evaluate the loading of the OIS, the BIS, the ASCs, and the network links by the traffic generated by the workstations and workcells throughout the site
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