ETHERNET NETWORKS

Ethernet is a flexible network, rather simple to use and nowadays universal. With low installation charges, it is relatively easy to maintain, leading in a very good cost / performance ratio. Anyway, Ethernet is a very complex matter, since it consists of a huge amount of varied technologies, and because Ethernet is evolving continuously by answering to the new needs generated by the continuously increasing capabilities of the emerging technologies.

This page lists some sources of technical informations and educational papers in relation with Ethernet basics, with industrial Ethernet networking, with some Ethernet implementations such as real time Ethernet ( RTE ) in association with IEEE 1588, Fast Ethernet, Gigabit Ethernet, and with subjects like Ethernet protocols, architectures, topologies, interfaces and more.

You will also find the presentation of some Ethernet utility software, such as Wireshark ( a popular and powerful protocol analyser ) or such as NTOPNG ( an Ethernet traffic analyser ) for instance.

After having read the good introduction to the local area network ( LAN ) protocols ( related to media, transmissions and topologies ), you can read two very complete and detailed documents on the Ethernet and Internet networks which can act as very good references.

• Internet networking handbook.

  www.cisco.com

  This mine of information could be considered as « THE » reference to Ethernet networking with its hundred of pages.

  If you are looking for more expert information or for the most detailed information as possible, such as network bridging, switching or routing, data integration technologies, broadband cabling and broadband data transfers, TCP / UDP protocols, ATM asynchronous transfer mode and more generaly the various asynchronous communication techniques, the different items concerning the IP internet protocol, network management, optical communication, storage networking, LAN local area networks, WAN wide area networks or mobile communication systems, available security technologies with a complete folder on VPN virtual private networking, QOS quality of services, or web cache memory techniques used to improve the performances and many other things, then you will get a great benefit by consulting this remarkable and very well structured reference manual.

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• Ethernet theory of operations. ( )

  ww1.microchip.com

  This paper reports on many subjects, from the protocol stack up to auto-crossover, illustrated with datagrams, timing diagrams and other schemes. It describes the frame encapsulation, the application, transport, network and physical / data link layers. It also presents a physical medium overview, and introduces to the Ethernet frame format, to control frames and to MAC addresses. Some other subjects carry on Ethernet system considerations such as stream timing, multiple access with collision detection ( CSMA/CD ), shared bus topology, full duplex, 10/100 Mb/s stream content, encoding overview, auto-negotiation and more.

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• Internet protocol overview. ( )

  https://fab.cba.mit.edu

  This document presents the basics of internet networking and the bases building its foundations, after having located its different fundamental protocols within the OSI communication layers.

  • The IP protocol

    The authors describe here the so called internet protocol, with the description of the IP packets, of the IPV4 addressing, of the address classes, of the sub-network addressing and of the subnetwork masking.

  • The transmission control TCP protocol

    The writers precise how connections are operating, what are the formats of the packets, which fields are building them, and what are the format and the possible usage of the user datagram protocol UDP.

  • The Internet application layers

    The team presents some application layers currently used within Internet, such as the file transfer protocol FTP, the network management protocol SNMP, the emailing protocol SMTP, Telnet, the domain name system DNS and so on …

  This introduction also shortly describes what are the ICMP control message protocol, the ARP address resolution protocol and how the data packets are routed.

This folder groups internal and external technical resources in relation with Ethernet networking. Particularly, Charles SPURGEON details the half-duplex Ethernet configuration in a guideline acting as a reference. In the Ethernet system section, he resumes the topologies, the different components and media, and all the fundamental knowledge needed to well understand the technology.

Charles SPURGEON - www.ethermanage.com

Automation engineers interested in industrial networking will discover here presentations, white papers, articles, FAQs and videos. They concern Ethernet 10 G UPON ( IEEE 802.3avTM ), Ethernet 10G base T ( IEEE 802.3an ), efficient energy Ethernet ( IEEE 802.3az ), higher speed Ethernet - 40 GB and 100 GB ( IEEE 802.3ba ), power over Ethernet POE or POE+ ( IEEE 802.3at ) and more.

www.ethernetalliance.org

Industrial Ethernet systems currently offer enough network stability and real time capability to build applications that would previously have been run under field buses. The attraction of these dedicated communicating systems rests in their use as a worldwide communications standard.

Industrial automation has the potential to be managed over the Ethernet at all levels : operations and control right through to the field level as part of a standardised data communications system. Reaching this goal requires replacement of existing field network protocols with real time protocols or/and to embed them into Ethernet frames, as it is done with the virtual serial port technique for instance. All that partially explains why the industrial communication networks are evolving constantly and converge more and more on Ethernet architectures, as it is shown in the following examples representing renewed technologies, which have sometimes adopted a new designation.

• Field buses.

  CC-Link, Ethernet-IP, Foundation Fieldbus HSE, Modbus TCP, Profinet and SafetyNet.

• Fast data buses.

  Ethercat, MACRO, Mechatrolink III, Powerlink, SERCOS III and SynqNet.

• Measuring instrumentation networks.

  HART-IP and LXI.

• Image transfer networks.

  Gige Vision.

• Sensors and actuators buses.

  Interbus, IO-Link and P-Net.

We also could eventually mention Arcnet with its « ArcnetPlus » version - its Ethernet adaptation trial, but the design started a little bit too late and other technologies won the run.

These slides explain first why Ethernet is needed and helpful in automation, what are the differences between office and factory usages, and which are the main Ethernet field networks in use ( 2004 ). Then, you will read an introduction to the real time requirements for automation, to the general behaviour of real time Ethernet ( RTE ) and how to improve performances in the Ethernet communication process. Finally, you will know the potential risks in automated plants with some considerations about safety on Ethernet and about safety standards for machines applications.

Professor Max FELSER - Berne University

http://felser.ch/

• Putting Industrial Ethernet to work in the field.
• Looking behind the automation protocols.
• Field bus, Ethernet and the reality of convergence.

• Fourteen Industrial Ethernet solutions under the spotlight.
• Ethernet/IP Motion receives top priority.

www.iebmedia.com

Time and synchronization requirements become more and more important for operating measurement, benchmarking, industrial automated plants, industrial networks and control systems in general. The ISO 1588 normalized standard defines a protocol which warrants precise clocks synchronization for measurement systems and for control systems using communication networks, computers, programmables controllers or distributed devices. Although this standard is often used in real time Ethernet systems ( RTE ), it is not attached to any specific technology. We can find this protocol in other systems and in other non Ethernet-based networks such as some control buses, some instrument networks or some field buses.

In extenso, the subject of this protocol consists only ( which is already a lot ) in a precise management of the synchronization between interactive devices ( which can concern data, hardware signal and anything else ) by proposing a set of well defined and well specified procedures and mechanisms. Any standard Ethernet network respecting this protocol acquires deterministic and real time features.

The 1588 standard is not the only used solution to add real time features to Ethernet. The latter can use Sercos, TTEThernet, SynUTC or NTP for example. It can ever use some functions provided by the GPS system ( which precision depends very narrowly of the precision offered by the satellits and relays embedded atomic clocks ). Real time Ethernet can also adopt other specific protocols, like the « shared reference time distributed clock » protocol used by the EtherCat control network for instance. Anyway, it is to note that the ISO 1588 standard is a robust and well proven solution responding to the constraints imposed by the control applications to the industrial Ethernet networks.

The « National ( USA ) Institute of Standard Technology » ( NIST ) provides a short introduction and some tutorials about the ISO 1588 standard. It also displays a link directory listing some useful IEEE 1588 related web sites.

www.nist.gov

Since Ethernet is more and more used for factory automation networking, from the field level up to the company management level, the amount of clients trying to access a same server is increasing while the amount of data to exchange is bigger and bigger. In the same time, more and more control applications such as motion control or machine vision require high performing real-time capabilities. Fast Ethernet ( in association with switched Ethernet ) is the economical solution to answer to these constraints, offering ten times higher performances for about the same costs.

This directory provides educational and technical documents introducing the system. The main themes are the 100 base-X physical sublayer and the 100 base-TX physical medium dependant.

www.iol.unh.edu

• Fast Ethernet and Gigabit Ethernet Technologies.

  This page resumes the basics of the technologies, what they are and how to use them, with the idea to guide readers while migrating and using such networks.

  www.lantronix.com

« Gigabit Ethernet » is one of the latest version of Ethernet ( with 10 Gbps Ethernet and 100 Gbps Ethernet right now ). It works with a wide bandwidth of 1000 Mbps ( 1 Gbps ), what is hundred times faster than the initial Ethernet in around 1973. Gigabit Ethernet is compatible with the previous versions of Ethernet, since it is using the same core technologies. It is used in the industry for machine vision networking applications such as Gige Vision for instance.

Each of these documents presents a good synthesis of many technologies in a few page.

• Gigabit Ethernet - Technology and solutions. ( )

  The Intel company explains us what about this technology consists in, why we need higher communication speed, and how to deploy high speed networks.

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• A 10 Gigabit Ethernet technology overview. ( )

  This Intel's white paper presents at first what is the 10 gigabit Ethernet standard and how different it is from the basic Ethernet standard. Then it defines how these techniques are placed in the market and in applications such as local area networks ( LAN ), wide area networks ( WAN ) and metropolitan area networks ( MAN ). Finally, it describes shortly the optical fibre usage into this standard and evaluates its future.

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• Using Segmentation to Increase Network Performance. ( )

  This Intel note explains why and how network segmentation improve networking performances, by adding ports, by adding servers, and by adding switches. Finally, the solutions for the servers are first to use embedded LAN on motherboard ( LOM ), and second to use multiple port network card ( NIC ).

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• Gigabit Ethernet Over Copper. ( )

  Intel tells us that although gigabit Ethernet has been designed to be wired with fibre cables, it can be wired with copper lines in an efficient way, mainly for economical reasons. The editor lists what important considerations have to be taken in account for deployment.

• Introduction to the architecture and to the organization.

  This paper introduces to the protocol architecture, to the physical interface, to encoding and Media Access Layer.

  [ Archives ]

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• « A survey of Gigabit Ethernet technology ».

  This Gigabit Ethernet synthesis presents the physical and the MAC layer, the gigabit independent interface, the buffered distributor and the topologies.

  Vijay Moorthy - Dpt. of computer sciences and engineering.

  Washington university in St Louis - www.cse.wustl.edu

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• Gigabit Ethernet knowledge base.

  This is a collection of well written and detailed technical overviews, where you can find an interesting presentation of the 1000 Base-T technology, and others in relation with the 1000 base-T physical coding sublayer, auto-negotiation and more.

  InterOperability Laboratory - www.iol.unh.edu

The following resources are mainly free and open source networking analysers for a very wide range of digital networks. These software are very efficient for all the Ethernet-based communication systems. In this website, you can also find some useful open source networking utilities focusing on digital security, intended to the TCP/IP networks too.

« Wireshark » ( formerly « Ethereal » ) is a very complete free and open source protocol analyser running on the most popular operating systems such as Unix, Linux or Windows. It is used by network professionals around the world for troubleshooting, analysis, software and protocol development. This very powerful tools allows industrial network testing, surveying and troubleshooting, since it can detect and analyse more than 1000 protocols ( in the version 1.10.2 ), including protocols and networks used in the industry. Thus, it can detect Can bus and CANopen, CIP, Ethercat, Ethernet IP, Ethernet Powerlink, Foundation Fieldbus, the different Modbus protocols ( Modbus RTU and Modbus TCP ), the Omron protocol « Fins », Wi-Fi, ZigBee and USB. Wireshark supports ISO 1588 protocol and many other real time Ethernet protocols too.

• Introduction to Wireshark and presentation of its and main features.
• The most frequently asked question ( FAQ ) about itself, including technical help, system, features, networks, programming and more.
• A very complete and detailed documentation including users guide, programmers guide and all about this software.

www.wireshark.org

This free and open source utility software ( under GNU Gpl V3 licence ) shows how an IP network is used. The informations are displayed in real time into a web browser. Thus, you can appreciate your network traffic, how the different protocols are distributed, what are the sources and the destinations of the various data exchanged and many more. This program can also be used as a data collector.

www.ntop.org