Enabling limited traffic scheduling in asynchronous ad hoc networks

We present work-in-progress developing a communication framework that addresses the communication challenges of the decentralized multihop wireless environment. The main contribution is the combination of a fully distributed, asynchronous power save mechanism with adaptation of the timing patterns defined by the power save mechanism to improve the energy and bandwidth efficiency of communication in multihop wireless networks. The possibility of leveraging this strategy to provide more complex forms of traffic management is explored

Innovative communication processors: A survey

Some existing innovative processors for execution of multilayer protocols are surveyed in order to identify performance limits and processor architectural trade-offs. The survey is restricted to packet or message handling processors with dedicated software and/or hardware. The processors are compared with respect to; performance, i.e. throughput and delay, to available protocols, and to implementation trade-offs, i.e. modularity, service access point accessibility, interface to host machine, dependability, implementation language, buffer handling, and context switch with state information. Of special interest are processors for protocols designed according to the OSI-model. One conclusion is that the implementation of buffer handling and context switch is crucial for the performance. The surveyed processors are divided into two categories; switches for X.25/ARPANET and controllers for Local Area Networks. The switches are often designed as multiprocessor systems, optimizing throughput, while the controllers often are designed with dedicated processors and chips, optimizing not only for throughput, but also for delay and for off-loading the host

The DTM packet service and protocol

The purpose of this document is to describe and specify the service of the DMT Packet Service (DPS) and Segmentation and Re-assembly (SAR) protocol, implementing the service. The document consists of two sections, one for the service and one for the protocol. The intent of the document is to specify, not to justify the design

SPIMS: A tool for protocol implementation performance measurements

In the combination of high-speed communication networks and layered protocol implementations, there is a large difference between the performance a user perceives at the application layer and the performance at the physical layer of the network. Still, there exists few general tools to aid a designer in tracing down the performance bottlenecks in the protocol implementations. In this paper we present such a tool which provides an environment where it is easy to develop, specify, and execute communication 'benchmarks', that can be used to compare the performance of different protocol stack implementations running on different hardware and operating systems. The tool measures user-oriented performance parameters such as throughput and response time without relying on special hardware or operating system support. The measurements are specified in a protocol independent specification language, thus different protocols can be compared by using the same measurement specification. The tool has been used to compare the performance of the ISODE OSI (FTAM) stack and the Arpa (FTP/TCP) protocols on Sun, MicroVAX and DS90 machines running UNIX

Surrounded by the Clouds A Comprehensive Cloud Reachability Study

In the early days of cloud computing, datacenters were sparsely deployed at distant locations far from end-users with high end-toend communication latency. However, today's cloud datacenters have become more geographically spread, the bandwidth of the networks keeps increasing, pushing the end-users latency down. In this paper, we provide a comprehensive cloud reachability study as we perform extensive global client-to-cloud latency measurements towards 189 datacenters from all major cloud providers. We leverage the well-known measurement platform RIPE Atlas, involving up to 8500 probes deployed in heterogeneous environments, e.g., home and offices. Our goal is to evaluate the suitability of modern cloud environments for various current and predicted applications. We achieve this by comparing our latency measurements against known human perception thresholds and are able to draw inferences on the suitability of current clouds for novel applications, such as augmented reality. Our results indicate that the current cloud coverage can easily support several latency-critical applications, like cloud gaming, for the majority of the world's population.Peer reviewe

ATM as a memory interconnect in a Desk Area Network

ATM has been successfully used in Wide Area Networks (WAN) and Local Area Networks (LAN). A possible next step in this evolution is to use ATM for cluster and desk area networks and to replace busses used for memory interconnect. This paper discusses how ATM can fulfill the functional and performance requirements in a memory interconnect, and the implications this will have for external ATM communication. We conclude that ATM can be used as a memory interconnect. It can meet the throughput requirements but will have problems with the latency requirements for the transfer of small cache lines. The fixed 48 byte payload in ATM results in inefficient use of bandwidth and increased latency. The ATM and the ATM Adaptation Layers do not have sufficient functionality and must be extended to offer the functionality required by the memory interconnect. Using ATM internally in the memory interconnect has a limited synergy effect when the system is connected to an ATM based LAN or WAN. 1. Introdu..

Innovative communication processors: A survey

Some existing innovative processors for execution of multilayer protocols are surveyed in order to identify performance limits and processor architectural trade-offs. The survey is restricted to packet or message handling processors with dedicated software and/or hardware. The processors are compared with respect to; performance, i.e. throughput and delay, to available protocols, and to implementation trade-offs, i.e. modularity, service access point accessibility, interface to host machine, dependability, implementation language, buffer handling, and context switch with state information. Of special interest are processors for protocols designed according to the OSI-model. One conclusion is that the implementation of buffer handling and context switch is crucial for the performance. The surveyed processors are divided into two categories; switches for X.25/ARPANET and controllers for Local Area Networks. The switches are often designed as multiprocessor systems, optimizing throughput, while the controllers often are designed with dedicated processors and chips, optimizing not only for throughput, but also for delay and for off-loading the host.Oríginal report number R87003.</p

On porting VMTP to the x-kernal

This report describes our port of Stenford transaction protocol VMTP from the BSD 4.3 UNIX kernal implementation to the x-kernal operating system from University of Arizona. The BSD UNIX kernal dependent functions in the VMTP Implementation are Identified. It is described how we have replaced these functions with corresponding parts from the x-kernal. In particular we describe how BSD UNIX "sockets" are replaced with x-kernal parts and how the BSD UNIX buffer system, "mbufs", is moved into user space. The ported version is the so called minimal implementation of VMTP. It only runs in the simulator of the x-kernal