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<html> <head> <meta content="en-us" http-equiv="Content-Language"> <meta content="text/html; charset=UTF-8" http-equiv="Content-Type"> <link type="text/css" rel="stylesheet" href="../../../../../css/ccna.css"> <script src="../../../../../js/framesetHelper.js" language="JavaScript"></script><script language="JavaScript"> window.scrollTo(0,0); function newPage(pageID) { alert("COMMING SOON!!\nThis feature is currently in development."); } function launchMoreInfo(oid) { dash = oid.indexOf('-'); sub1 = oid.substring(0,dash); sub2 = oid.substring(dash+1); // this is an URL base on the // system that generated the static // download of the curriculum. httpref = "http://nomar.sdf.cisco.com/servlet/org.cli.delivery.rendering.servlet.MIServlet/Static=true,LMSID=DTUI,Engine=dynamic,Theme=cnamstheme,Style=ccna,Language=en,Version=2,RootID=knet-v214aCV47051/CHAPID=null/RLOID=null/RIOID=null/"; newref = httpref + sub1 +"/"+ sub2 +"/moreinfoframeset.html"; //alert("new newref :\n" + newref); window.open(newref,'MoreInfo','toolbar=no,status=yes,menubar=no,location=no,scrollbars=yes,height=442,width=756,left=20,top=20,resizable=yes') } function launchContentResource(contentID) { top.currentSupport = 0; 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FDDI is particularly popular as a campus backbone technology or in Internet critical applications where faults cannot be tolerated. FDDIs specifications should be reviewed with the students.</p> <p>This TI relates to CCNA Certification Exam Objective #1.</p> </span></td> </tr> </table> </td> </tr> </table> </td> </tr> </table><p>In the mid 1980s, high speed engineering workstations pushed the capabilities of existing Ethernet and Token Ring to their limits. Engineers needed a LAN that could support their workstations, and their new applications. At the same time, system managers became concerned with network reliability issues as mission critical applications were implemented on high speed networks.</p><p>The ANSI X3T9.5 standards committee, to resolve these issues, produced the <i>Fiber Distributed Data Interface (FDDI)</i> standard. After completing the specifications, ANSI submitted FDDI to the International Organization for Standardization (ISO). The ISO then created an international version of the FDDI that is completely compatible with the ANSI standard version.</p><p>Although FDDI implementations are not as common as Ethernet or Token Ring, FDDI has a substantial following and it continues to grow as its costs decrease. FDDI is frequently used as a backbone technology and to connect high speed computers in a LAN.</p><p>FDDI has four specifications:</p><ol><li> <i>Media Access Control (MAC)</i> - defines how the medium is accessed, including:<ul type="disc"><li>Frame format</li><li>Token handling</li><li>Addressing</li><li>Algorithm for calculating a cyclic redundancy check and error recovery mechanisms</li></ul> </li><li> <i>Physical Layer Protocol (PHY)</i> - defines data encoding/decoding procedures, including:<ul type="disc"><li>Clocking requirements</li><li>Framing</li><li>Other functions</li></ul> </li><li> <i>Physical Layer Medium (PMD)</i> - defines the characteristics of the transmission medium, including:<ul type="disc"><li>Fiber optic link</li><li>Power levels</li><li>Bit error rates</li><li>Optical components</li><li>Connectors</li></ul> </li><li> <i>Station Management (SMT)</i> - defines the FDDI station configuration, including:<ul type="disc"><li>Ring configuration</li><li>Ring control features</li><li>Station insertion and removal</li><li>Initialization</li><li>Fault isolation and recovery</li><li>Scheduling</li><li>Collection of statistics</li></ul> </li></ol></td> </tr> </table> </td> </tr></table> <p> </p> <table width="100%" cellspacing="0" cellpadding="2" border="0" valign="bottom"> <tr> <td></td> </tr> </table> </body></html>⌨️ 快捷键说明
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