Ethernet

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Description

TutorialEthernet
Ethernet
April 11, 2006Trademarks and Copyrights
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Sujets

• Lance
• Liste des personnages des Chevaliers d'Émeraude
• Réseau local virtuel
• Collision
• Byte
• Réseau privé

Informations

• Publié par: Zewyung
• Nombre de lectures: 118
• Langue: English

Extrait

ernet

Ethernet

Tutorial

April 11, 2006

Acrobat and Reader are registered trademarks of Adobe Systems, Incorporated AppleTalk is a registered trademark of Apple Computer NetBIOS is a registered trademark of the IBM corporation NetBUEI is a registered trademark of the IBM Corporation UNIX is a registered trademark of UNIX System Laboratories, Inc., and is exclusively licensed by the X/Open Company, Ltd. Windows is a registered trademark of the Microsoft Corporation Windows NT is a registered trademark of the Microsoft Corporation

Trademarks and Copyrights

All other products or services mentioned in this document are identified by the trademarks, service marks, or product names as designated by the companies that market those products or services or own those marks. Inquiries concerning such products, services, or marks should be made directly to those companies. This document and its contents are provided by Fujitsu Network Communications Inc. (Fujitsu) for guidance purposes only. This document is provided as is with no warranties or representations whatsoever, either express or implied, including without limitation the implied warranties of merchantability and fitness for purpose. Fujitsu does not warrant or represent that the contents of this document are error free. Furthermore, the contents of this document are subject to update and change at any time without notice by Fujitsu, since Fujitsu reserves the right, without notice, to make changes in equipment design or components as progress in engineering methods may warrant. No part of the contents of this document may be copied, modified, or otherwise reproduced without the express written consent of Fujitsu.

Unpublished work and only distributed under restriction. Copyright © Fujitsu Network Communications Inc. All Rights Reserved.

Tutorial

Introduction ................................................................................. 1 Distribution Method .............................................................. 1 Ethernet ...................................................................................... 3 Ethernet History ................................................................... 3 Ethernet Standards .............................................................. 3 Fast Ethernet .............................................................................. 4 Gigabit Ethernet.......................................................................... 4 10 Gigabit Ethernet..................................................................... 5 LAN PHY .............................................................................. 5 WAN PHY ............................................................................ 5 10GBase Interfaces ............................................................. 5 LAN PHY/WAN PHY Sublayers.................................................. 7 Physical Coding Sublayer .................................................... 7 Physical Medium Attachment ............................................... 7 Physical Medium Dependent ............................................... 7 Ethernet Frames ......................................................................... 9 Ethernet Address ................................................................. 9 EthernetAccess........................................................................10 Full Duplex ......................................................................... 11 EthernetEquipment..................................................................12 Bridges...............................................................................12 Routers............................................................................... 12 Switches.............................................................................13 Hubs/Repeaters.................................................................13 EthernetProtocols....................................................................15 IPAddresses............................................................................17 SubnetMask......................................................................17 Network Classes ................................................................ 17 Dot Address ....................................................................... 17 Spanning Tree Protocol ............................................................ 18 Rapid Spanning Tree Protocol.................................................. 19 EthernetMedia.........................................................................21

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Ethernet Networks .................................................................... 22 LAN..................................................................................... 22 WAN ................................................................................... 22 Private Networks ....................................................................... 23 ELINE ................................................................................. 23 ELAN .................................................................................. 23 Metro Ethernet Forum ........................................................ 23 VLAN......................................................................................... 25 VLANTagging....................................................................25 Ethernet Topologies .................................................................. 27 Tree Topology .................................................................... 27 Ethernet Over SONET .............................................................. 29 The MAN/WAN Connection................................................ 29 Encapsulated Ethernet.............................................................. 31 Concatenated VTs.............................................................. 31 Differential Delay ................................................................ 31 EOS Protocols .......................................................................... 33 LAPS .................................................................................. 33 GFP .................................................................................... 33 EOS Advantages ...................................................................... 34 Ethernet Acronyms ................................................................... 35 Ethernet Acronyms (Cont) ........................................................ 36 Tutorial Review ......................................................................... 37 Review Answers ....................................................................... 41

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Introduction This self-study tutorial on Ethernet and Ethernet over SONET satisfies a prerequisite needed for attendance at Fujitsu Educational Services training. The tutorial gives a general overview of Ethernet: History Standards Frames Access Protocols Media Networks Topologies Equipment Additionally, the tutorial provides specific SONET information as it relates to transporting Ethernet over SONET. The tutorial ends with a 25-question review of the information covered in the tutorial. Any student who completes the tutorial can answer the review questions and, by missing no more than four questions, satisfy a prerequisite requirement for Fujitsu courses. If more than four questions are missed, the student should revisit the tutorial to ensure familiarity with all concepts and terms in the tutorial before attending class.

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Distribution Method The Ethernet tutorial can be viewed using Acrobat ® Reader ® and is available at the following Internet address: http:www.fnc.fujitsu.com/services/pdfs/edservethernet.pdf Additional tutorials are available at these sites:  ATM: http:www.fnc.fujitsu.com/services/pdfs/edservatm.pdf  SONET: http:www.fnc.fujitsu.com/services/pdfs/edservsonet.pdf

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Supplement 802.3a 802.3c 802.3d 802.3i 802.3j 802.3u 802.3x 802.3z 802.3ab 802.3ac 802.3ad 802.3ae 802.3ah 802.3as 802.3at

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Year 1985 1986 1987 1990 1993 1995 1997 1998 1999 1998 2000 2002 2004 2005 2005

Table 1: Ethernet Standards Description 10Base-2 (thin Ethernet) 10 Mb/s repeater specifications (clause 9) FOIRL (fiber link) 10Base-T (twisted pair) 10Base-F (fiber optic) 100Base-T (Fast Ethernet and autonegotiation) Full duplex 1000Base-X (Gigabit Ethernet) 1000Base-T (Gigabit Ethernet over twisted pair) VLAN tag (frame size extension to 1522 bytes) Parallel links (link aggregation) 10-Gigabit Ethernet Ethernet in the first mile Frame expansion Power over Ethernet Plus

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Ethernet Ethernet, a physical layer local area network (LAN) technology, is nearly 30 years old. In the last three decades, it has become the most widely used LAN technology because of its speed, low cost, and relative ease of installation. This is combined with wide computer-market acceptance and the ability to support the majority of network protocols. Ethernet History Robert Metcalfe, an engineer at Xerox, first described the Ethernet network system he invented in 1973. The simple, yet innovative and, for its time, advanced system was used to interconnect computer workstations, sending data between workstations and printers. Metcalfes Ethernet was modeled after the Aloha network developed in the 1960s at the University of Hawaii. However, his system detected collisions between simultaneously transmitted frames and included a listening process before frames were transmitted, thereby greatly reducing collisions. Although Metcalfe and his coworkers received patents for Ethernet and an Ethernet repeater, and Ethernet was wholly-owned by Xerox, Ethernet was not designed nor destined to be a proprietary system. It would soon became a worldwide standard.

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Ethernet Standards The first Metcalfe system ran at 2.94 Mb/s, but by 1980 DEC, Intel, and Xerox (DIX) issued a DIX Ethernet standard for 10 Mb/s Ethernet systems. That same year, the Institute of Electrical and Electronics Engineers (IEEE) commissioned a committee to develop open network standards. In 1985, this committee published the portion of the standard pertaining to Ethernet (based on the DIX standard)IEEE 802.3 Carrier Sense Multiple Access with Collision Detection (CSMA/CD) Access Method and Physical Layer Specifications. Even though the IEEE title does not mention Ethernet, Metcalfes original term for his network system had caught on, and IEEE 802.3 was and is referred to as the Ethernet standard. Note:The IEEE standard was called 802 because work on it started in February 1980. As described in Table 1, many more Ethernet standards have been created since 1985. The IEEE standards have been adopted by the American National Standards Institute (ANSI) and by the International Organization of Standards (ISO). ISO standardization means that companies and organizations around the world use these standards when manufacturing Ethernet products and installing Ethernet network systems.

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Fast Ethernet While 10 Mb/s seemed very fast in the mid-1980s, the need for speed resulted in a 1995 standard (IEEE 802.3u) for 100 Mb/s Ethernet over wire or fiber-optic cable. Although the 100Base-T standard was close to 10Base-T, network designers had to determine which customers needed the extra bandwidth. Because there was a choice of bandwidths, the standard also allowed for equipment that could autonegotiate the two speeds. In other words, if an Ethernet device was transmitting or receiving from a 10 Mb/s network, it could support that network. If the network operated at 100 Mb/s, the same device could switch automatically to the higher rate. Ethernet networks then could be 10 Mb/s or 100 Mb/s (Fast Ethernet) and connected with 10/100 Mb/s Ethernet devices that automatically switched network speeds.

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Gigabit Ethernet Gigabit Ethernet works much the same way as 10 Mb/s and 100 Mb/s Ethernet, only faster. It uses the same IEEE 802.3 frame format, full duplex, and flow control methods. Additionally, it takes advantage of CSMA/CD when in half-duplex mode, and it supports simple network management protocol (SNMP) tools. Gigabit Ethernet takes advantage of jumbo frames to reduce the frame rate to the end host. Standard Ethernet frame sizes are between 64 and 1518 bytes. Jumbo frames are between 64 and 9215 bytes. Because larger frames translate to lower frame rates, using jumbo frames on Gigabit Ethernet links greatly reduces the number of packets (from more than 80,000 to less than 15,000 per second) that are received and processed by the end host. Gigabit Ethernet can be transmitted over CAT 5 cable and optical fiber such as the following: 1000Base-CXShort distance transport (copper) 1000Base-SX850 nm wave length (fiber optics) 1000Base-LX1300 nm wave length (fiber optics)

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10 Gigabit Ethernet The operation of 10 Gigabit Ethernet is similar to that of lower speed Ethernets. It maintains the IEEE 802.3 Ethernet frame size and format that preserves layer 3 and greater protocols. However, 10 Gigabit Ethernet only operates over point-to-point links in full-duplex mode. Additionally, it uses only multimode and single mode optical fiber for transporting Ethernet frames. Note:Operation in full-duplex mode eliminates the need for CSMA/CD. The 10 Gigabit Ethernet standard (IEEE 802.3ae) defines two broad physical layer network applications:  Local area network (LAN) PHY  Wide area network (WAN) PHY LAN PHY The LAN PHY operates at close to the 10 Gigabit Ethernet rate to maximize throughput over short distances. Two versions of LAN PHY are standardized:  Serial (10GBASE-R)  4-Channel course wave divi sion multiplexing (CWDM) (10GBASE-X) The 10GBASE-R uses a 64B/66B encoding system that raises the 10 Gigabit Ethernet line rate from a nonencoded 9.58 Gb/s to 10.313 Gb/s. The 10GBASE-X still uses 8B/10B encoding because all of the 2.5 Gb/s CWDM channels it employs are parallel and run at 3.125 Gb/s after encoding. The MAC to PHY data rate for both LAN PHY versions is 10 Gb/s. Encoding is used so that long runs of ones and zeros that could cause clock and data problems are greatly reduced.

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WAN PHY The WAN PHY supports connections to circuit-switched SONET networks. Besides the sublayers added to the LAN PHY (discussed in the following two pages), the WAN PHY adds another element called the WAN interface sublayer (WIS). The WIS takes data payload and puts it into a 9.58464 Gb/s frame that can be transported at a rate of 9.95328 Gb/s. The WIS does not support every SONET feature, but it carries out enough overhead functions (including timing and framing) to make the Ethernet frames recognizable and manageable by the SONET equipment they pass through. 10GBase Interfaces Just as Fast Ethernet and Gigabit Ethernet have multiple interfaces, 10 Gigabit Ethernet has seven interfaces referred to in Table 2. Table 2: 10GBASE-x Interfaces Interface PHY Optics 10GBASE-SR LAN 850 nm serial 10GBASE-LR LAN 1310 nm serial 10GBASE-ER LAN 1550 nm serial 10GBASE-LX4 LAN 4 x 1310 nm CWDM 10GBASE-SW WAN 850 nm serial 10GBASE-LW WAN 1310 nm serial 10GBASE-EW WAN 1550 nm serial

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Figure 1: LAN PHY/WAN PHY Sublayers

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LAN PHY/WAN PHY Sublayers The PHY is a circuit block at the physical layer that includes the following sublayers (see Figure 1):  Physical coding sublayer (PCS)  Physical medium attachment (PMA)  Physical medium dependent (PMD) Physical Coding Sublayer The PCS encodes and decodes the data stream between the MAC and PHY layer. There are three categories for the PCS: 10GBASE-RSerially encoded (64B/66B); 10.3 Gb/s rate not SONET compatible (LAN PHY) 10GBASE-XSerially enc oded (8B/10B); used for wavelength division multiplexing (WDM) transmissions (LAN PHY) 10GBASE-WSerially encoded (64B/66B); compatible with SONET standards for a 10 Gb/s WAN (WAN PHY) Physical Medium Attachment The PMD is an optional interface for connection to optical modules. The two PMD interfaces are: 10 Gigabit Ethernet attachm ent unit interface (XAUI) 10 Gigabit Ethernet 16- bit interface (XSBI)

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The XAUI is an interface to specialized 10 Gigabit Ethernet optical modules and system backplanes. It supports 4 SERDES transmit and 4 SERDES receive channels for 8B/10B encoding. Note:SERDES stands for SERializer/DESerializer. SERDES is used in high speed communications to convert data from/to serial and parallel data streams. The XSBI is a serial optics interface for LAN and WAN PHY applications. Intermediate and long reach optical modules use this interface. It requires more power and more pins than an XAUI. Physical Medium Dependent Distance objectives are met by using the physical medium dependent sublayer. Four different PMDs are defined to support single and multimode optical fibers: 850 nm serialMMF, 500 MHz/km, up to 65 meters 1310 nm serialSMF, up to 10 km 1550 nm serialSMF, up to 40 km 1310 nm CWDMMMF, 500 MHz/km, up to 300 meters 1310 nm CWDMSMF, 10 km

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