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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta name="generator" content="HTML Tidy, see www.w3.org" /><title>ISDN</title><meta name="GENERATOR" content="Modular DocBook HTML Stylesheet Version 1.7" /><link rel="HOME" title="FreeBSD Handbook" href="index.html" /><link rel="UP" title="Advanced Networking" href="advanced-networking.html" /><link rel="PREVIOUS" title="Diskless Operation" href="network-diskless.html" /><link rel="NEXT" title="Network Address Translation" href="network-natd.html" /><link rel="STYLESHEET" type="text/css" href="docbook.css" /></head><body class="SECT1" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#840084"alink="#0000FF"><div class="NAVHEADER"><table summary="Header navigation table" width="100%" border="0" cellpadding="0"cellspacing="0"><tr><th colspan="3" align="center">FreeBSD Handbook</th></tr><tr><td width="10%" align="left" valign="bottom"><a href="network-diskless.html"accesskey="P">Prev</a></td><td width="80%" align="center" valign="bottom">Chapter 24 Advanced Networking</td><td width="10%" align="right" valign="bottom"><a href="network-natd.html"accesskey="N">Next</a></td></tr></table><hr align="LEFT" width="100%" /></div><div class="SECT1"><h1 class="SECT1"><a id="NETWORK-ISDN" name="NETWORK-ISDN">24.7 ISDN</a></h1><p>A good resource for information on ISDN technology and hardware is <ahref="http://www.alumni.caltech.edu/~dank/isdn/" target="_top">Dan Kegel's ISDNPage</a>.</p><p>A quick simple road map to ISDN follows:</p><ul><li><p>If you live in Europe you might want to investigate the ISDN card section.</p></li><li><p>If you are planning to use ISDN primarily to connect to the Internet with an InternetProvider on a dial-up non-dedicated basis, you might look into Terminal Adapters. Thiswill give you the most flexibility, with the fewest problems, if you changeproviders.</p></li><li><p>If you are connecting two LANs together, or connecting to the Internet with adedicated ISDN connection, you might consider the stand alone router/bridge option.</p></li></ul><p>Cost is a significant factor in determining what solution you will choose. Thefollowing options are listed from least expensive to most expensive.</p><div class="SECT2"><h2 class="SECT2"><a id="NETWORK-ISDN-CARDS" name="NETWORK-ISDN-CARDS">24.7.1 ISDNCards</a></h2><i class="AUTHORGROUP"><span class="CONTRIB">Contributed by</span> HellmuthMichaelis.</i> <p>FreeBSD's ISDN implementation supports only the DSS1/Q.931 (or Euro-ISDN) standardusing passive cards. Starting with FreeBSD 4.4, some active cards are supportedwhere the firmware also supports other signaling protocols; this also includes the firstsupported Primary Rate (PRI) ISDN card.</p><p>The <b class="APPLICATION">isdn4bsd</b> software allows you to connect to other ISDNrouters using either IP over raw HDLC or by using synchronous PPP: either by using kernelPPP with <var class="LITERAL">isppp</var>, a modified <ahref="http://www.FreeBSD.org/cgi/man.cgi?query=sppp&sektion=4"><spanclass="CITEREFENTRY"><span class="REFENTRYTITLE">sppp</span>(4)</span></a> driver, or byusing userland <a href="http://www.FreeBSD.org/cgi/man.cgi?query=ppp&sektion=8"><spanclass="CITEREFENTRY"><span class="REFENTRYTITLE">ppp</span>(8)</span></a>. By usinguserland <a href="http://www.FreeBSD.org/cgi/man.cgi?query=ppp&sektion=8"><spanclass="CITEREFENTRY"><span class="REFENTRYTITLE">ppp</span>(8)</span></a>, channelbonding of two or more ISDN B-channels is possible. A telephone answering machineapplication is also available as well as many utilities such as a software 300 Baudmodem.</p><p>Some growing number of PC ISDN cards are supported under FreeBSD and the reports showthat it is successfully used all over Europe and in many other parts of the world.</p><p>The passive ISDN cards supported are mostly the ones with the Infineon (formerlySiemens) ISAC/HSCX/IPAC ISDN chipsets, but also ISDN cards with chips from Cologne Chip(ISA bus only), PCI cards with Winbond W6692 chips, some cards with the Tiger300/320/ISACchipset combinations and some vendor specific chipset based cards such as the AVMFritz!Card PCI V.1.0 and the AVM Fritz!Card PnP.</p><p>Currently the active supported ISDN cards are the AVM B1 (ISA and PCI) BRI cards andthe AVM T1 PCI PRI cards.</p><p>For documentation on <b class="APPLICATION">isdn4bsd</b>, have a look at <ttclass="FILENAME">/usr/share/examples/isdn/</tt> directory on your FreeBSD system or atthe <a href="http://www.freebsd-support.de/i4b/" target="_top">homepage of isdn4bsd</a>which also has pointers to hints, erratas and much more documentation such as the <ahref="http://people.FreeBSD.org/~hm/" target="_top">isdn4bsd handbook</a>.</p><p>In case you are interested in adding support for a different ISDN protocol, acurrently unsupported ISDN PC card or otherwise enhancing <bclass="APPLICATION">isdn4bsd</b>, please get in touch with Hellmuth Michaelis <codeclass="EMAIL"><<a href="mailto:hm@FreeBSD.org">hm@FreeBSD.org</a>></code>.</p><p>For questions regarding the installation, configuration and troubleshooting <bclass="APPLICATION">isdn4bsd</b>, a <ahref="http://lists.FreeBSD.org/mailman/listinfo/freebsd-isdn"target="_top">freebsd-isdn</a> mailing list is available.</p></div><div class="SECT2"><h2 class="SECT2"><a id="AEN37572" name="AEN37572">24.7.2 ISDN Terminal Adapters</a></h2><p>Terminal adapters (TA), are to ISDN what modems are to regular phone lines.</p><p>Most TA's use the standard Hayes modem AT command set, and can be used as a drop inreplacement for a modem.</p><p>A TA will operate basically the same as a modem except connection and throughputspeeds will be much faster than your old modem. You will need to configure <ahref="ppp.html">PPP</a> exactly the same as for a modem setup. Make sure you set yourserial speed as high as possible.</p><p>The main advantage of using a TA to connect to an Internet Provider is that you can doDynamic PPP. As IP address space becomes more and more scarce, most providers are notwilling to provide you with a static IP anymore. Most stand-alone routers are not able toaccommodate dynamic IP allocation.</p><p>TA's completely rely on the PPP daemon that you are running for their features andstability of connection. This allows you to upgrade easily from using a modem to ISDN ona FreeBSD machine, if you already have PPP set up. However, at the same time any problemsyou experienced with the PPP program and are going to persist.</p><p>If you want maximum stability, use the kernel <a href="ppp.html">PPP</a> option, notthe <a href="userppp.html">userland PPP</a>.</p><p>The following TA's are known to work with FreeBSD:</p><ul><li><p>Motorola BitSurfer and Bitsurfer Pro</p></li><li><p>Adtran</p></li></ul><p>Most other TA's will probably work as well, TA vendors try to make sure their productcan accept most of the standard modem AT command set.</p><p>The real problem with external TA's is that, like modems, you need a good serial cardin your computer.</p><p>You should read the <ahref="../../../../doc/en_US.ISO8859-1/articles/serial-uart/index.html"target="_top">FreeBSD Serial Hardware</a> tutorial for a detailed understanding of serialdevices, and the differences between asynchronous and synchronous serial ports.</p><p>A TA running off a standard PC serial port (asynchronous) limits you to115.2 Kbs, even though you have a 128 Kbs connection. To fully utilize the128 Kbs that ISDN is capable of, you must move the TA to a synchronous serialcard.</p><p>Do not be fooled into buying an internal TA and thinking you have avoided thesynchronous/asynchronous issue. Internal TA's simply have a standard PC serial port chipbuilt into them. All this will do is save you having to buy another serial cable and findanother empty electrical socket.</p><p>A synchronous card with a TA is at least as fast as a stand-alone router, and with asimple 386 FreeBSD box driving it, probably more flexible.</p><p>The choice of synchronous card/TA v.s. stand-alone router is largely a religiousissue. There has been some discussion of this in the mailing lists. We suggest you searchthe <a href="../../../../search/index.html" target="_top">archives</a> for the completediscussion.</p></div><div class="SECT2"><h2 class="SECT2"><a id="AEN37602" name="AEN37602">24.7.3 Stand-alone ISDNBridges/Routers</a></h2><p>ISDN bridges or routers are not at all specific to FreeBSD or any other operatingsystem. For a more complete description of routing and bridging technology, please referto a networking reference book.</p><p>In the context of this section, the terms router and bridge will be usedinterchangeably.</p><p>As the cost of low end ISDN routers/bridges comes down, it will likely become a moreand more popular choice. An ISDN router is a small box that plugs directly into yourlocal Ethernet network, and manages its own connection to the other bridge/router. It hasbuilt in software to communicate via PPP and other popular protocols.</p><p>A router will allow you much faster throughput than a standard TA, since it will beusing a full synchronous ISDN connection.</p><p>The main problem with ISDN routers and bridges is that interoperability betweenmanufacturers can still be a problem. If you are planning to connect to an Internetprovider, you should discuss your needs with them.</p><p>If you are planning to connect two LAN segments together, such as your home LAN to theoffice LAN, this is the simplest lowest maintenance solution. Since you are buying theequipment for both sides of the connection you can be assured that the link willwork.</p><p>For example to connect a home computer or branch office network to a head officenetwork the following setup could be used:</p><div class="EXAMPLE"><a id="AEN37614" name="AEN37614"></a><p><b>Example 24-1. Branch Office or Home Network</b></p><p>Network uses a bus based topology with 10 base 2 Ethernet (``thinnet''). Connectrouter to network cable with AUI/10BT transceiver, if necessary.</p><p><img src="advanced-networking/isdn-bus.png" /></p><p>If your home/branch office is only one computer you can use a twisted pair crossovercable to connect to the stand-alone router directly.</p></div><div class="EXAMPLE"><a id="AEN37628" name="AEN37628"></a><p><b>Example 24-2. Head Office or Other LAN</b></p><p>Network uses a star topology with 10 base T Ethernet (``Twisted Pair'').</p><p><img src="advanced-networking/isdn-twisted-pair.png" /></p></div><p>One large advantage of most routers/bridges is that they allow you to have 2 <spanclass="emphasis"><i class="EMPHASIS">separate independent</i></span> PPP connections to 2separate sites at the <span class="emphasis"><i class="EMPHASIS">same</i></span> time.This is not supported on most TA's, except for specific (usually expensive) models thathave two serial ports. Do not confuse this with channel bonding, MPP, etc.</p><p>This can be a very useful feature if, for example, you have an dedicated ISDNconnection at your office and would like to tap into it, but do not want to get anotherISDN line at work. A router at the office location can manage a dedicated B channelconnection (64 Kbps) to the Internet and use the other B channel for a separate dataconnection. The second B channel can be used for dial-in, dial-out or dynamically bonding(MPP, etc.) with the first B channel for more bandwidth.</p><p>An Ethernet bridge will also allow you to transmit more than just IP traffic. You canalso send IPX/SPX or whatever other protocols you use.</p></div></div><div class="NAVFOOTER"><hr align="LEFT" width="100%" /><table summary="Footer navigation table" width="100%" border="0" cellpadding="0"cellspacing="0"><tr><td width="33%" align="left" valign="top"><a href="network-diskless.html"accesskey="P">Prev</a></td><td width="34%" align="center" valign="top"><a href="index.html"accesskey="H">Home</a></td><td width="33%" align="right" valign="top"><a href="network-natd.html"accesskey="N">Next</a></td></tr><tr><td width="33%" align="left" valign="top">Diskless Operation</td><td width="34%" align="center" valign="top"><a href="advanced-networking.html"accesskey="U">Up</a></td><td width="33%" align="right" valign="top">Network Address Translation</td></tr></table></div><p align="center"><small>This, and other documents, can be downloaded from <ahref="ftp://ftp.FreeBSD.org/pub/FreeBSD/doc/">ftp://ftp.FreeBSD.org/pub/FreeBSD/doc/</a>.</small></p><p align="center"><small>For questions about FreeBSD, read the <ahref="http://www.FreeBSD.org/docs.html">documentation</a> before contacting <<ahref="mailto:questions@FreeBSD.org">questions@FreeBSD.org</a>>.<br />For questions about this documentation, e-mail <<ahref="mailto:doc@FreeBSD.org">doc@FreeBSD.org</a>>.</small></p></body></html>⌨️ 快捷键说明
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