Collision Avoidance Tree networks

The Collision Avoidance Tree is a new local area network based on a hardware device called collision avoidance switch, which arbitrates random access to a shared communications channel. Collision Avoidance Tree combines the benefits of random access (low delay when traffic is light; simple, distributed, and therefore robust, protocols) with concurrency of transmission, excellent network utilization and suitability for the domain of high-speed, optical networking.The Collision Avoidance Tree is classified in two classes: the Collision Avoidance Single Broadcast (CASB) Tree and the Collision Avoidance Multiple Broadcast (CAMB) Tree. The CASB Tree allows only a single transmission on the network at a given time, while the CAMB Tree is more general and allows concurrent transmissions on the network.This paper describes network architectures (e.g., station and switch protocols) and designs and implementations of the CASB and CAMB Trees. Performance results derived from analyses, simulations, measurements of experimental networks are also presented

A VLSI implementation of the collision avoidance switch protocol for CAMB tree LANs

To solve a performance bottle neck in random access LANs due to packet collisions and their resolution, collision avoidance switches are introduced. These switches allow random access protocols to achieve high performance by resolving collisions among packets. A conventional hardware implementation of these switches is the use of TTL chips. In this implementation; a handful of TTL chips are required to forma single switch (e.g., 18 TTL chips are needed for an implementation of the CAMB switch [7]). Thus, implementation of a complete network, which requires several of these switches, could very well result in a large and complex hardware system.Today's modern chip technology allows us to pack large quantity of logic in a single chip. By transferring the conventional implementation of the collision avoidance switches into a VLSI chip, the complexity of the resultant hardware is greatly reduced, not to mention the improvement in hardware performance and ease of packaging.This report provides an overall study of the collision avoidance protocols for the tree LANs with emphasis on the implementation of collision avoidance switches. Hardware implementations of sorne of these switches are discussed. And a VLSI implementation of the CAMB switch protocol is introduced

Traffic control in coherence-multiplexed networks

Coherence multiplexing (CM) is a relatively unknown form of optical CDMA, which is particulary suitable in medium bit rate, short-range optical networks like LANs. The main purpose of the technique is to allow multiple users to transmit through a common optical fiber simultaneously. When this number is too large, however, the BER will become unacceptably high. Therefore a protocol is needed to control the traffic. In this paper several protocols are presented. An adapted version of synchronous TDMA, two new protocols and a central control unit will be proposed and discussed. Finally, the protocols will be compared with respect to performance and practical implementation aspects

Ethernet - a survey on its fields of application

During the last decades, Ethernet progressively became the most widely used local area networking (LAN) technology. Apart from LAN installations, Ethernet became also attractive for many other fields of application, ranging from industry to avionics, telecommunication, and multimedia. The expanded application of this technology is mainly due to its significant assets like reduced cost, backward-compatibility, flexibility, and expandability. However, this new trend raises some problems concerning the services of the protocol and the requirements for each application. Therefore, specific adaptations prove essential to integrate this communication technology in each field of application. Our primary objective is to show how Ethernet has been enhanced to comply with the specific requirements of several application fields, particularly in transport, embedded and multimedia contexts. The paper first describes the common Ethernet LAN technology and highlights its main features. It reviews the most important specific Ethernet versions with respect to each application field’s requirements. Finally, we compare these different fields of application and we particularly focus on the fundamental concepts and the quality of service capabilities of each proposal

Tree LANS with collision avoidance : protocol, switch architecture, and performance

Packet collisions and their resolution create a performance bottleneck in random access LANs. A hardware solution to this problem is to use collision avoidance switches. These switches allow the implementation of random access protocols without the penalty of collisions among packets. We review and compare the designs of some tree LANs that use collision avoidance switches. They have the potential of combining the benefits of random access (low delay when traffic is light, simple and distributed, and therefore robust, protocols) with excellent network utilization and concurrency of transmission. The collision avoidance LANs we review are broadcast star, Hubnet-like tree, Tinker-Tree, and a treenet that allows concurrent broadcasts within non-intersecting subtrees. After this review, we present a slotted-time, infinite user analysis of the broadcast star network

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

Preparation and characterisation of irradiated waste eggshells as oil adsorbent

Adsorption method had been developed by using natural organic adsorbent for the removal of oil because of its ability to bind the oil molecules into the surface of adsorbent. In this study, chicken eggshells waste was used and it undergoes irradiation process with four different amount of dose which was 0.5 kGy, 1.0 kGy, 1.5 kGy, and 2.0 kGy by using Gamma Cell Irradiator. Three equipment had been used for the characterization process which were the Scanning Electron Microscope (SEM), Energy Dispersive X-ray spectroscopy (EDX), and Fourier-Transform Infrared Spectroscopy (FTIR). The adsorption experiment was conducted to calculate the sorption efficiency by using different mass of samples. The result showed that irradiated chicken eggshells powder with 2.0 kGy amount of radiation dose has a best performance as oil adsorbent