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| author | Sven Eisenhauer <sven@sven-eisenhauer.net> | 2023-11-10 15:11:48 +0100 |
|---|---|---|
| committer | Sven Eisenhauer <sven@sven-eisenhauer.net> | 2023-11-10 15:11:48 +0100 |
| commit | 33613a85afc4b1481367fbe92a17ee59c240250b (patch) | |
| tree | 670b842326116b376b505ec2263878912fca97e2 /Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_4/content.html | |
| download | Studium-master.tar.gz Studium-master.tar.bz2 | |
Diffstat (limited to 'Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_4/content.html')
| -rw-r--r-- | Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_4/content.html | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_4/content.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_4/content.html new file mode 100644 index 0000000..4ed41d2 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_4/content.html @@ -0,0 +1,165 @@ +<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns="http://www.w3.org/TR/REC-html40">
+
+<head>
+<meta http-equiv="Content-Language" content="en-us">
+<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
+
+
+
+<title>Content</title>
+<base target="_self">
+</head>
+
+<body background="../../images/bg.gif" topmargin="0" leftmargin="0" marginheight="0" marginwidth="0" onLoad="window.focus();" link="#808080" vlink="#808080" alink="#808080">
+
+<table border="0" cellpadding="0" cellspacing="0" width="100%">
+ <tr>
+ <td bgcolor="#336666" width="18" valign="top">
+ <img border="0" src="../../images/content_lines.gif" width="16" height="25">
+ <img border="0" src="../../images/transdot.gif" width="2" height="1"></td>
+ <td bgcolor="#336666"><b><font face="Arial" size="2" color="#FFFFFF">2.2</font></b></td>
+ <td bgcolor="#336666"><img border="0" src="../../images/transdot.gif" width="10" height="1"></td>
+ <td bgcolor="#336666" width="100%">
+ <strong><font face="Arial" size="2" color="#FFFFFF">WAN Technologies</font></strong></td>
+ <td width="9" bgcolor="#336666"> </td>
+ </tr>
+ <tr>
+ <td bgcolor="#669999" height="25" width="18"> </td>
+ <td bgcolor="#669999" height="25"><b><font face="Arial" size="2" color="#FFFFFF">
+ 2.2.4</font></b></td>
+ <td bgcolor="#669999"><img border="0" src="../../images/transdot.gif" width="10" height="1"></td>
+ <td bgcolor="#669999" height="25" width="100%"><strong>
+ <font face="Arial" size="2" color="#FFFFFF">X.25</font></strong></td>
+ <td bgcolor="#669999" height="25" width="9"> </td>
+ </tr></table>
+
+<table border="0" cellpadding="0" cellspacing="0" width="95%" bordercolor="#111111">
+
+ <tr>
+ <td width="15"></td>
+ <td>
+ <font face="Arial" size="2">In response to the expense of leased
+ lines, telecommunications providers introduced packet-switched
+ networks using shared lines to reduce costs. The first of these
+ packet-switched networks was standardized as the X.25 group of
+ protocols. X.25 provides a low bit rate shared variable capacity that
+ may be either switched or permanent.
+ <img border="0" src="../../images/1.gif" align="absmiddle" width="12" height="12"></font><p>
+ <font face="Arial" size="2">X.25 is a network-layer protocol and
+ subscribers are provided with a network address. Virtual circuits can
+ be established through the network with call request packets to the
+ target address. The resulting SVC is
+ identified by a channel number. Data packets labeled with the channel
+ number are delivered to the corresponding address. Multiple channels
+ can be active on a single connection.</font></p>
+ <p><font face="Arial" size="2">Subscribers connect to the X.25 network
+ with either leased lines or dialup connections. X.25 networks can also
+ have pre-established channels between subscribers that provide a
+
+ PVC.</font></p>
+ <p><font face="Arial" size="2">X.25 can be very cost effective because
+ tariffs are based on the amount of data delivered rather than
+ connection time or distance. Data can be delivered at any rate up to
+ the connection capacity. This provides some flexibility. X.25 networks
+ are usually low capacity, with a maximum of 48 kbps. In addition, the
+ data packets are subject to the delays typical of shared networks.</font></p>
+ <p><font face="Arial" size="2">X.25 technology is no longer widely
+ available as a WAN technology in the US. Frame Relay has replaced X.25 at many service provider locations.</font></p>
+ <p><font face="Arial" size="2">Typical X.25 applications are
+ point-of-sale card readers. These readers use X.25 in dialup mode to
+ validate transactions on a central computer. Some enterprises also use
+ X.25 based value-added networks (VAN) to transfer Electronic Data
+ Interchange (EDI) invoices, bills of lading, and other commercial
+ documents. For these applications, the low bandwidth and high latency
+ are not a concern, because the low cost makes the use of X.25
+ affordable.</font></p>
+ <TABLE bgcolor="#B0AFAF" width="95%" border="0" cellspacing="0" cellpadding="0">
+ <TR>
+ <TD valign="top">
+ <TABLE bgcolor="#669999" width="100%" cellspacing="0" cellpadding="0" border="0">
+ <TR>
+ <TD width="5">
+ <img border="0" src="../../images/lab_toplft.gif" width="116" height="23"></TD>
+ <TD><IMG alt="" height="1" width="3" src="../../images/s.gif"></TD><TD align="right" valign="top">
+ <IMG alt="" src="../../images/corner_ur_7.gif" width="7" height="7"></TD>
+ </TR>
+ </TABLE>
+
+ <TABLE bgcolor="#B0AFAF" width="100%" cellspacing="0" cellpadding="0" border="0">
+ <TR>
+ <TD>
+ <TABLE width="100%" cellpadding="2" cellspacing="0" border="0" bordercolor="#111111">
+ <TR>
+ <TD bgcolor="#ffffff" width="15"> </TD>
+ <TD bgcolor="#ffffff"><font FACE="Arial" SIZE="2" COLOR="#000000">
+ <p><font color="#808080">
+ <a href="javascript:void(0)" onClick="window.open('../../activities/ch02/activity_2_2_4.html','Interactivity','width=740,height=390,toolbar=0,resizable=yes,scrollbars=0,screenX=26,screenY=38,left=26,top=38');">
+ <img border="0" src="../../images/media_icon.gif" width="25" height="25"></a> <b>
+ <a onClick="window.open('../../activities/ch02/activity_2_2_4.html','Interactivity','width=740,height=390,toolbar=0,resizable=yes,scrollbars=0,screenX=26,screenY=38,left=26,top=38');" href="javascript:void(0)">Interactive Media Activity</a></b></font></p>
+ </font><font FACE="Arial" SIZE="2" COLOR="#808080">
+ <p>Checkbox: WAN Technologies X.25</p>
+ <p>Upon completing this activity, the student
+ will be able to identify the characteristics associated with an
+ X.25 connection.</p>
+ </font><font FACE="Arial" SIZE="2" COLOR="#000000">
+ <p><IMG alt="" height="2" width="1" src="../../images/s.gif"></p></TD>
+ </TR>
+ </TABLE>
+ </TD>
+ </TR>
+ </TABLE>
+ </TD>
+ </TR>
+ </TABLE>
+
+
+
+
+ <TABLE bgcolor="#B0AFAF" width="95%" border="0" cellspacing="0" cellpadding="0">
+ <TR>
+ <TD valign="top">
+ <TABLE bgcolor="#669999" width="100%" cellspacing="0" cellpadding="0" border="0">
+ <TR>
+ <TD width="5">
+ <img border="0" src="../../images/lab_toplft.gif" width="116" height="23"></TD>
+ <TD><IMG alt="" height="1" width="3" src="../../images/s.gif"></TD><TD align="right" valign="top">
+ <IMG alt="" src="../../images/corner_ur_7.gif" width="7" height="7"></TD>
+ </TR>
+ </TABLE>
+
+ <TABLE bgcolor="#B0AFAF" width="100%" cellspacing="0" cellpadding="0" border="0">
+ <TR>
+ <TD>
+ <TABLE width="100%" cellpadding="2" cellspacing="0" border="0" bordercolor="#111111">
+ <TR>
+ <TD bgcolor="#ffffff" width="15"> </TD>
+ <TD bgcolor="#ffffff"><font FACE="Arial" SIZE="2" COLOR="#000000">
+ <p><font color="#808080">
+ <img border="0" src="../../images/links_icon.gif" width="25" height="25">
+ <b>Web Links</b></font></p>
+ </font><font FACE="Arial" SIZE="2" COLOR="#808080">
+
+ <p>X.25 Protocol<p>
+ <a target="_blank" href="http://www2.rad.com/networks/1996/x25/x25.htm">
+ http://www2.rad.com/networks/1996/ x25/x25.htm</a></font></p>
+
+ <p>
+ <IMG alt="" height="2" width="1" src="../../images/s.gif"></p>
+ </TD>
+ </TR>
+ </TABLE>
+ </TD>
+ </TR>
+ </TABLE>
+ </TD>
+ </TR>
+ </TABLE><p>
+
+ <font face="Arial" size="2"> </font>
+ </td>
+ </tr>
+ </table>
+
+</body>
+
+</html>
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