77 lines
5.0 KiB
HTML
77 lines
5.0 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 http-equiv="Content-Type" content="text/html; charset=utf-8" />
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<meta name="DC.Type" content="concept" />
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<meta name="DC.Title" content="Why some LAN connections fail" />
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<meta name="abstract" content="Sometimes an incorrectly configured controller description can cause a connection failure." />
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<meta name="description" content="Sometimes an incorrectly configured controller description can cause a connection failure." />
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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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<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>Why some LAN connections fail</title>
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</head>
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<body id="why_connections_fail"><a name="why_connections_fail"><!-- --></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">Why some LAN connections fail</h1>
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<div><p>Sometimes an incorrectly configured controller description can
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cause a connection failure.</p>
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<p> The cases here involve the incorrect configuration of
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the adapter address, source service access point <a href="rzajuhigherlayersoverlanprotocols.htm#higher_layers_over_lan_protocols__ssaps_and_dsaps">(SSAP)</a>, or destination service access point <a href="rzajuhigherlayersoverlanprotocols.htm#higher_layers_over_lan_protocols__ssaps_and_dsaps">(DSAP)</a> parameters. </p>
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<p>For more information about how these parameters influence a successful
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connection, see <a href="rzajuunderstandingstationids.htm#understanding_station_ids">How
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LAN devices identify themselves</a>. For other causes of a connection failure,
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see <a href="rzajuunderstandingwhentoconnect.htm#understanding_when_to_connect">Which
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device initiates the connection</a>. </p>
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<p><strong>The remote system does not connect:</strong></p>
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<p>If your controller description uses <a href="rzajudialmode.htm#dial_mode">dial
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mode</a>, it is not unusual for the system to receive message CPA58E0 (<tt class="msgph">Controller
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not replying</tt>) or CPA57EF (<tt class="msgph">Contact not successful</tt>).
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Remote systems or controller descriptions that do not vary on can cause one
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of these messages to appear.</p>
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<p><strong>Your system does not connect:</strong></p>
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<p>If your controller description uses <a href="rzajuanswermode.htm#answer_mode">answer
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mode</a>, you might receive the message CPI591A (<tt class="msgph">Controller is online,
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varied off, or not recognized by the local system</tt>). There are some
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things that can cause this message to appear:</p>
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<ul><li>The connection requested by the remote system does not exist on the local
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system. The local system searches for this connection (that is indicated by
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combining the local adapter address, the DSAP, and the SSAP) in all varied-on
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controller descriptions.</li>
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<li>The controller description does not refer to the line
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description that can answer the call.</li>
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</ul>
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<p><strong>Solution:</strong></p>
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<p>To correct any of the above problems, do one or more of these steps:</p>
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<ul><li>On either side of the connection, verify that the controller description
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has the correct combination of adapter address, SSAP, and DSAP.</li>
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<li>Enter the line description that can accept the call into the Switched
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line list field of the controller description. See <a href="rzajuunderstandingconnestablishment.htm#understanding_conn_establishment">Understanding
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connection establishment</a> for information about the relationship between
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line descriptions and controller descriptions.</li>
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<li>Vary on the correct controller description (use the Work with Configuration
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Status (WRKCFGSTS) command to vary on the controller).</li>
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<li>Verify that the local and remote adapters are wired into the network correctly.</li>
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</ul>
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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="rzajutroubleshootingtokenring.htm" title="The server has tools to help you locate and resolve errors.">Troubleshoot token ring</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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