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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_7/content.html | |
| download | Studium-master.tar.gz Studium-master.tar.bz2 | |
Diffstat (limited to 'Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_7/content.html')
| -rw-r--r-- | Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_7/content.html | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_7/content.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_7/content.html new file mode 100644 index 0000000..04e5270 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_7/content.html @@ -0,0 +1,152 @@ +<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">
+ 2.2.7</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">DSL</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">Digital Subscriber Line (DSL) technology
+ is a broadband technology that uses existing twisted-pair telephone
+ lines to transport high-bandwidth data to service subscribers. DSL
+ service is considered broadband, as opposed to the baseband service
+ for typical LANs. Broadband refers to a technique which uses multiple
+ frequencies within the same physical medium to transmit data. The term
+ xDSL covers a number of similar yet competing forms of DSL
+ technologies:
+ <img border="0" src="../../images/1.gif" align="absmiddle" width="12" height="12"></font><ul>
+ <li><font face="Arial" size="2">Asymmetric DSL (ADSL)</font></li>
+ <li><font face="Arial" size="2">Symmetric DSL (SDSL)</font></li>
+ <li><font face="Arial" size="2">High Bit Rate DSL (HDSL)</font></li>
+ <li><font face="Arial" size="2">ISDN (like) DSL (IDSL)</font></li>
+ <li><font face="Arial" size="2">Rate Adaptive DSL (RADSL)</font></li>
+ <li><font face="Arial" size="2">Consumer DSL (CDSL), also called
+ DSL-lite or G.lite</font></li>
+ </ul>
+ <p>
+ <font face="Arial" size="2">DSL technology
+ allows the service provider to offer high-speed network services to
+ customers, utilizing installed local loop copper lines. DSL
+ technology allows the local loop line to be used for normal
+ telephone voice connection and an always-on
+ connection for instant network connectivity. Multiple
+ DSL subscriber lines are multiplexed into a single, high capacity link
+ by the use of a DSL Access Multiplexer (DSLAM) at the provider
+ location. DSLAMs incorporate TDM
+ technology to aggregate many subscriber lines into a less cumbersome
+ single medium, generally a T3/DS3 connection. Current DSL technologies
+ are using sophisticated coding and modulation techniques to achieve
+ data rates up to 8.192 Mbps. </font></p>
+ <p><font face="Arial" size="2">The voice channel of a standard
+ consumer telephone covers the frequency range of 330 Hz to 3.3 KHz. A
+ frequency range, or window, of 4 KHz is regarded as the requirements
+ for any voice transmission on the local loop. DSL technologies place
+ upload (upstream) and download (downstream) data transmissions at
+ frequencies above this 4 KHz window. This technique is what allows
+ both voice and data transmissions to occur simultaneously on a DSL
+ service.
+ <img border="0" src="../../images/2.gif" align="absmiddle" width="12" height="12"></font></p>
+ <p><font face="Arial" size="2">The two basic types of DSL technologies
+ are asymmetric (ADSL) and symmetric (SDSL). All forms of DSL service
+ are categorized as ADSL or SDSL and there are several varieties of
+ each type. Asymmetric service provides
+ higher download or downstream bandwidth to the user than upload
+ bandwidth. Symmetric service provides the same capacity in both
+ directions.</font></p>
+ <p><font face="Arial" size="2">The different varieties of DSL provide
+ different bandwidths, with capabilities exceeding those of a T1 or E1
+ leased line. The transfer rates are dependent on the actual length of
+ the local loop and the type and condition of its cabling. For
+ satisfactory service, the loop must be less than 5.5 kilometers (3.5
+ miles). DSL availability is far from universal, and there are a wide
+ variety of types, standards, and emerging standards. It is not a
+ popular choice for enterprise computer departments to support home
+ workers. Generally, a subscriber cannot choose to connect to the
+ enterprise network directly, but must first connect to an Internet
+ service provider (ISP). From
+ here, an IP connection is made through the Internet to the enterprise.
+ Thus, security risks are incurred. To address security concerns, DSL
+ services provide capabilities for using Virtual Private Network (VPN)
+ connections to a VPN server, which is typically located at the
+ corporate site. </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_7.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_7.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 Digital Subscriber Line (DSL)</p>
+ <p>Upon completing this activity, the student
+ will be able to identify the characteristics associated with DSL
+ connections.</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>
+
+
+ <p>
+
+ </td>
+ </tr>
+ </table>
+
+</body>
+
+</html>
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