99 lines
6.2 KiB
HTML
99 lines
6.2 KiB
HTML
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<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE html
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PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html lang="en-us" xml:lang="en-us">
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<head>
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<meta name="DC.Type" content="reference" />
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<meta name="DC.Title" content="Ethernet frame format" />
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<meta name="abstract" content="Know how to interpret the data contained in your Ethernet frames by understanding the frame formatting." />
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<meta name="description" content="Know how to interpret the data contained in your Ethernet frames by understanding the frame formatting." />
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<meta name="copyright" content="(C) Copyright IBM Corporation 1999, 2006" />
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<!-- All rights reserved. Licensed Materials Property of IBM -->
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<!-- US Government Users Restricted Rights -->
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<link rel="stylesheet" type="text/css" href="./ibmdita.css" />
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<link rel="stylesheet" type="text/css" href="./ic.css" />
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<title>Ethernet frame format</title>
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</head>
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<body id="rzajyethernetframeformat"><a name="rzajyethernetframeformat"><!-- --></a>
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<!-- Java sync-link --><script language="Javascript" src="../rzahg/synch.js" type="text/javascript"></script>
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<h1 class="topictitle1">Ethernet frame format</h1>
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<div><p>Know how to interpret the data contained in your Ethernet frames
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by understanding the frame formatting.</p>
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<div class="section"><p>While tracing LAN communications, you might need to look at the
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transmitted frames. To understand the data that is contained in the frame,
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you must know how it is formatted. The figures below show the frame format
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of two Ethernet standards: IEEE 802.3 and Ethernet version 2.</p>
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</div>
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<div class="section"><p id="rzajyethernetframeformat__frame_check_sequence"><a name="rzajyethernetframeformat__frame_check_sequence"><!-- --></a>The Frame Check Sequence (FCS) is a
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part of the frame put in place to verify that the information each frame contains
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is not damaged during transmission. If a frame is corrupted during transmission,
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the FCS on the frame will not match with the recipient's calculated FCS. Any
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frames that do not match the calculated FCS will be discarded.</p>
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</div>
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<div class="section"><h4 class="sectiontitle">IEEE 802.3 frame format</h4>
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<div class="tablenoborder"><table cellpadding="4" cellspacing="0" summary="" class="singleborder" frame="border" border="1" rules="all"><tbody><tr><td align="center" valign="top" width="13.992537313432834%">Starting Delimiter (1 byte)</td>
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<td align="center" valign="top" width="16.417910447761194%">Destination Address (6 bytes)</td>
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<td align="center" valign="top" width="13.432835820895523%">Source Address (6 bytes)</td>
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<td align="center" valign="top" width="11.753731343283583%">Length (2 bytes)</td>
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<td align="center" valign="top" width="24.62686567164179%">LLC header and Information field (46 -
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1500 bytes)</td>
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<td align="center" valign="top" width="19.776119402985074%">Frame Check Sequence (4 bytes)</td>
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</tr>
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</tbody>
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</table>
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</div>
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</div>
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<div class="section"><h4 class="sectiontitle">Ethernet version 2 frame format</h4>
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<div class="tablenoborder"><table cellpadding="4" cellspacing="0" summary="" class="singleborder" frame="border" border="1" rules="all"><tbody><tr><td align="center" valign="top" width="14.473684210526317%">Starting Delimiter (1 byte)</td>
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<td align="center" valign="top" width="16.917293233082706%">Destination Address (6 bytes)</td>
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<td align="center" valign="top" width="14.473684210526317%">Source Address (6 bytes)</td>
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<td align="center" valign="top" width="11.654135338345863%">Type (2 bytes)</td>
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<td align="center" valign="top" width="22.55639097744361%">Information field (46 - 1500 bytes)</td>
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<td align="center" valign="top" width="19.924812030075188%">Frame Check Sequence (4 bytes)</td>
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</tr>
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</tbody>
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</table>
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</div>
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<p>Ethernet version 2 supports SNA by placing the IEEE 802.2 LLC header
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and data into the information field. It also puts value <span>X'80D5'</span> into
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the Type field. This shows the frame format.</p>
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<div class="tablenoborder"><table cellpadding="4" cellspacing="0" summary="" class="singleborder" frame="border" border="1" rules="all"><tbody><tr><td align="center" valign="top" width="13.840155945419102%">Starting Delimiter</td>
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<td align="center" valign="top" width="16.764132553606238%">Destination Address</td>
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<td align="center" valign="top" width="14.619883040935672%">Source Address</td>
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<td align="center" valign="top" width="12.085769980506821%">Type (80D5)</td>
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<td align="left" valign="top" width="22.807017543859647%">Information field (Length, Padding, LLC
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header, Data)</td>
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<td align="center" valign="top" width="19.883040935672515%">Frame Check Sequence</td>
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</tr>
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</tbody>
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</table>
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</div>
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<div class="note"><span class="notetitle">Note:</span> i5/OS™ does
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not have integrated support for SNA over Gigabit Ethernet or 10 Gbps Ethernet.
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Enterprise Extender or AnyNet is required to run SNA over 1 Gpbs or 10 Gbps
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Ethernet. For more information, see the "APPC, APPN, and HPR" topic.</div>
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</div>
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</div>
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<div>
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<div class="familylinks">
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<div class="parentlink"><strong>Parent topic:</strong> <a href="rzajyunderstandingethernetsupport.htm" title="Understand and use Ethernet frames, connections, and functions.">Ethernet support</a></div>
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</div>
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<div class="relinfo"><strong>Related information</strong><br />
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<div><a href="../rzahj/rzahjovr.htm">APPC, APPN, and HPR</a></div>
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</div>
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</div>
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</body>
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</html>
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