Search results for "ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS"
showing 10 items of 449 documents
An evaluation of switched ethernet and linux traffic control for real-time transmission
2008
Switched Ethernet networks are spreading to industrial environments more are more. The current trend is using them at all levels of a factory, replacing this way field-buses and other industrial networks. Switched Ethernet lacks the drawback of the non-deterministic collision resolution of coax cabling. However there are still some sources of indeterminism, mostly due to contention problems in message queues at switches and network interfaces. These problems can be dealt with using traffic control mechanisms for packet prioritisation and scheduling. These features have been largely inaccessible in Ethernet for a long time but, nowadays, they are widely available in industrial switches and a…
Gigabit Ethernet backbones with active loops
2001
The current standard Ethernet switches are based on the Spanning Tree (ST) protocol. Their most important restriction is that they can not work when the topology has active loops. In fact, the ST protocol selects a tree from the real topology by blocking the links that are not involved in the tree. This restriction produces a network traffic unbalancing behavior saturating those link near the root switch while rest of links will be idle or with a very low utilization. This paper proposes a new transparent switch protocol for Gigabit Ethernet backbones that considerably improves the performance of current ones. The proposed protocol is named ALOR for Active Loops and Optimal Routing. ALOR pr…
SmartARP: merging IP and MAC addressing for low-cost gigabit Ethernet networks
1999
Abstract Address Resolution Protocol (ARP) is one of the key TCP/IP stack protocols, used on LANs to map 32 bit IP addresses into 48 bit hardware addresses. Regular ARP uses MAC layer broadcasts to perform the mapping. In this paper a new server-based ARP extension (smartARP) is proposed, which allows the extension of ARP functionality beyond a single MAC layer broadcast domain. Compared to regular IP router, smartARP together with simple broadcast-filtering switches presents a low-cost alternative for forwarding packets between MAC layer broadcast domains. SmartARP is transparent to existing IP hosts, operates independent of LAN speed, and scales for big networks.
Adding Real-Time Networking and QoS Capabilities to RTLinux-GPL
2006
This paper presents an architecture to build distributed embedded real-time systems in the RTLinux-GPL platform. The architecture (built in a layered fashion) has being built around open source projects ranging from Ethernet drivers to a CORBA environment. The paper focuses on those layers that give support for QoS and real-time networking over Ethernet networks. The main ideas are: to accomplish deterministic access times by using a TDMA protocol over Ethernet and to multiplex different types of traffic in that real-time network, providing different service types (QoS) to each type of traffic without jeopardizing the a priori guarantee of the system's real-time properties. Traffic types in…
LSOM: A Link State protocol Over MAC addresses for metropolitan backbones using Optical Ethernet switches
2003
This paper presents a new protocol named "Link State Over MAC" (LSOM) for Optical Ethernet switches to allow the use of active loop topologies, like meshes, in Metropolitan Area Networks (MAN) or even Wide Area Networks (WAN) backbone. In this respect, LSOM is an alternative to a ring topology as proposed in draft IEEE 802.17 Resilient Packet Ring (RPR) or a tree topology using IEEE802. 1D Rapid Spanning Tree Protocol (RSTP). LSOM provides higher scalability and is able to achieve better bandwidth utilization and lower latency than RSTP and RPR. Simulation results for 4-node and 9-node topologies show that LSOM can improve throughput over RPR by a factor of up to 1.7. Furthermore, full free…
ZERO: An Efficient Ethernet-Over-IP Tunneling Protocol
2013
An Ethernet over IPv4 tunneling protocol is proposed, which categorizes all Ethernet frames to be tunneled into NICE and UGLY frames. The UGLY frames are tunneled by traditional methods, such as UDP or GRE encapsulation, resulting in substantial overhead due to additional headers and fragmentation usually required to transport long Ethernet frames over IP network typically limited to MTU=1,500 bytes. Meanwhile the NICE Ethernet frames are tunneled without any overhead as plain IPv4 packets due to non-traditional reuse of “fragment offset” or “identification” field in the IP header. It is shown that for typical Internet traffic transported over Ethernet, the proposed ZERO tunneling protocol …
DEMO: Unconventional WiFi-ZigBee communications without gateways
2014
Nowadays, the overcrowding of ISM bands is becoming an evident limitation for the performance and widespread usage of 802.11 and 802.15.4 technologies. In this demo, we prove that it is possible to opportunistically exploit the inter-technology interference between 802.11 and 802.15.4 to build an unconventional low-rate communication channel and signalling protocol, devised to improve the performance of each contending technology. Differently from previous solutions, inter-technology communications do not require the deployment of a gateway with two network interfaces, but can be activated (when needed) directly between two heterogeneous nodes, e.g. a WiFi node and a ZigBee node. This capab…
Enabling Backoff for SCM Wake-Up Radio: Protocol and Modeling
2017
In sub-carrier modulation (SCM) wake-up radio (WuR) enabled wireless sensor networks, a node can initiate data transmission at any instant of time. In this letter, we propose to activate a backoff procedure before sending wake-up calls (WuCs) in order to avoid potential collisions among WuCs. Consequently, no backoff is needed for the main radio after a WuC is received. A discrete-time Markov chain model is developed to evaluate the performance. Numerical results on network throughput, energy efficiency, average delay, and collision probability reveal the benefits of enabling backoff for SCM-WuRs, especially under heavy traffic loads or saturated traffic conditions.
A survey on pseudonym changing strategies for Vehicular Ad-Hoc Networks
2017
International audience; The initial phase of the deployment of vehicular ad-hoc networks (VANETs) has begun and many research challenges still need to be addressed. Location privacy continues to be in the top of these challenges. Indeed, both academia and industry agreed to apply the pseudonym changing approach as a solution to protect the location privacy of VANETs' users. However, due to the pseudonyms linking attack, a simple changing of pseudonym shown to be inefficient to provide the required protection. For this reason, many pseudonym changing strategies have been suggested to provide an effective pseudonym changing. Unfortunately, the development of an effective pseudonym changing st…
Investigating Low Level Protocols for Wireless Body Sensor Networks
2016
The rapid development of medical sensors has increased the interest in Wireless Body Area Network (WBAN) applications where physiological data from the human body and its environment is gathered, monitored, and analyzed to take the proper measures. In WBANs, it is essential to design MAC protocols that ensure adequate Quality of Service (QoS) such as low delay and high scalability. This paper investigates Medium Access Control (MAC) protocols used in WBAN, and compares their performance in a high traffic environment. Such scenario can be induced in case of emergency for example, where physiological data collected from all sensors on human body should be sent simultaneously to take appropria…