56 lines
2.4 KiB
HTML
56 lines
2.4 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
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<!--Converted with LaTeX2HTML 96.1-c (Feb 29, 1996) by Nikos Drakos (nikos@cbl.leeds.ac.uk), CBLU, University of Leeds -->
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<HTML>
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<HEAD>
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<TITLE>Other Types of Hardware</TITLE>
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</HEAD>
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<BODY LANG="EN">
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<A HREF="node1.html"><IMG WIDTH=65 HEIGHT=24 ALIGN=BOTTOM ALT="contents" SRC="contents_motif.gif"></A> <BR>
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<B> Next:</B> <A HREF="node11.html">The Internet Protocol</A>
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<B>Up:</B> <A HREF="node7.html">TCP/IP Networks</A>
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<B> Previous:</B> <A HREF="node9.html">Ethernets</A>
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<BR> <P>
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<H2><A NAME="SECTION003330000">Other Types of Hardware</A></H2>
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<A NAME="introtcpipotherhardware"></A>
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In larger installations, such as Groucho Marx University,
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Ethernet is usually not the only type of equipment used.
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At Groucho Marx University, each department's LAN is linked
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to the campus backbone, which is a fiber optics cable running
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FDDI (<em>Fiber Distributed Data Interface</em>). FDDI uses an
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entirely different approach to transmitting data, which basically
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involves sending around a number of <em>tokens</em>, with a station only
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being allowed to send a frame if it captures a token. The main advantage
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of FDDI is a speed of up to 100-Mbps, and a maximum cable length of
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up to 200-km.
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<P>
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For long-distance network links, a different type of equipment is
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frequently used, which is based on a standard named X.25. Many so-called
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Public Data Networks, like Tymnet in the U.S., or Datex-P in Germany,
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offer this service. X.25 requires special hardware, namely a Packet
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Assembler/Disassembler or <em>PAD</em>. X.25 defines a set of networking
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protocols of its own right, but is nevertheless frequently used to
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connect networks running TCP/IP and other protocols. Since IP packets
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cannot simply be mapped onto X.25 (and vice versa), they are simply
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encapsulated in X.25 packets and sent over the network.
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<P>
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<A NAME="384"></A>
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<A NAME="385"></A>
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<A NAME="386"></A>
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<A NAME="387"></A>
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Frequently, radio amateurs use their equipment to network their
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computers; this is called <em>packet radio</em> or <em>ham radio</em>. The
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protocol used by ham radios is called AX.25, which was derived from
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X.25.
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<P>
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Other techniques involve using slow but cheap serial lines for
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dial-up access. These require yet another protocol for transmission
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of packets, such as SLIP or PPP, which will be described below.
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<P>
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<BR> <HR>
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<P><ADDRESS>
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<I>Andrew Anderson <BR>
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Thu Mar 7 23:22:06 EST 1996</I>
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</ADDRESS>
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</BODY>
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</HTML>
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