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ccna

            for transferring messages between a subarea node and a PU 2, using
            local addresses. See also <a href="t.html#REF22292"><i>TH</i></a>.</font></font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><a name="REF13855"><b><font size="2" face="Arial">FID3</font></b></a>
        <dl>
          <dd><font face="Arial"><strong><font size="2">Format indicator 3</font></strong><font size="2">.
            One of several formats that an SNA TH can use. An FID3 TH is used
            for transferring messages between a subarea node and a PU 1, using
            local addresses. See also <a href="t.html#REF22292"><i>TH</i></a>.</font></font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><a name="REF23526"><b><font size="2" face="Arial">FID4</font></b></a>
        <dl>
          <dd><font face="Arial"><strong><font size="2">Format indicator 4</font></strong><font size="2">.
            One of several formats that an SNA TH can use. An FID4 TH
            encapsulates messages between two subarea nodes that are capable of
            supporting virtual and explicit routes. See also <a href="t.html#REF22292"><i>TH</i></a>.</font></font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><b><font size="2" face="Arial">field-replaceable
        unit</font></b>
        <dl>
          <dd><font size="2" face="Arial">See <a href="f.html#REF12263"><i>FRU</i></a>.</font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><b><font size="2" face="Arial">file
        transfer</font></b>
        <dl>
          <dd><font size="2" face="Arial">Popular network application that
            allows files to be moved from one network device to another.</font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><b><font size="2" face="Arial">File
        Transfer, Access, and Management</font></b>
        <dl>
          <dd><font size="2" face="Arial">See <a href="f.html#REF27816"><i>FTAM</i></a>.</font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><b><font size="2" face="Arial">File
        Transfer Protocol</font></b>
        <dl>
          <dd><font size="2" face="Arial">See <a href="f.html#REF29054"><i>FTP</i></a>.</font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><a name="REF17494"><b><font size="2" face="Arial">filter</font></b></a>
        <dl>
          <dd><font size="2" face="Arial">Generally, a process or device that
            screens network traffic for certain characteristics, such as source
            address, destination address, or protocol, and determines whether to
            forward or discard that traffic based on the established criteria.</font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><a name="REF19817"><b><font size="2" face="Arial">FIP</font></b></a>
        <dl>
          <dd><font face="Arial"><strong><font size="2">FDDI Interface Processor</font></strong><font size="2">.
            Interface processor on the Cisco 7000 series routers. The FIP
            supports SASs, DASs, dual homing, and optical bypass, and contains a
            16-mips processor for high-speed (100-Mbps) interface rates. The FIP
            complies with ANSI and ISO FDDI standards.</font></font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><b><font size="2" face="Arial">firewall</font></b>
        <dl>
          <dd><font size="2" face="Arial">Router or access server, or several
            routers or access servers, designated as a buffer between any
            connected public networks and a private network. A firewall router
            uses access lists and other methods to ensure the security of the
            private network.</font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><b><font size="2" face="Arial">firmware</font></b>
        <dl>
          <dd><font size="2" face="Arial">Software instructions set permanently
            or semipermanently in ROM.</font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><b><font size="2" face="Arial">fish
        tape</font></b>
        <dl>
          <dd><font size="2" face="Arial">Retractable coil of steel tape used to
            guide cable through a wall from above or below.</font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><b><font size="2" face="Arial">flapping</font></b>
        <dl>
          <dd><font size="2" face="Arial">Routing problem where an advertised
            route between two nodes alternates (flaps) back and forth between
            two paths due to a network problem that causes intermittent
            interface failures.</font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><b><font size="2" face="Arial">Flash
        memory</font></b>
        <dl>
          <dd><font size="2" face="Arial">Technology developed by Intel and
            licensed to other semiconductor companies. Flash memory is
            nonvolatile storage that can be electrically erased and
            reprogrammed. Allows software images to be stored, booted, and
            rewritten as necessary.</font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><a name="REF32409"><b><font size="2" face="Arial">flash
        update</font></b></a>
        <dl>
          <dd><font size="2" face="Arial">Routing update sent asynchronously in
            response to a change in the network topology. Compare with <a href="r.html#REF28102"><i>routing
            update</i></a>.</font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><a name="REF36698"><b><font size="2" face="Arial">fldsup
        account</font></b></a>
        <dl>
          <dd><font size="2" face="Arial">One of the four default user accounts
            that are created in the factory on each LightStream 2020 ATM switch.
            The fldsup account is for the use of field service personnel. Its
            default interface is the bash shell. See also <a href="b.html#REF22876"><i>bash</i></a>.</font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><a name="flood"><b><font size="2" face="Arial">flooding</font></b></a>
        <dl>
          <dd><font size="2" face="Arial">Traffic passing technique used by
            switches and bridges in which traffic received on an interface is
            sent out all of the interfaces of that device except the interface
            on which the information was originally received.</font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><b><font size="2" face="Arial">flow</font></b>
        <dl>
          <dd><font size="2" face="Arial">Stream of data traveling between two
            endpoints across a network (for example, from one LAN station to
            another). Multiple flows can be transmitted on a single circuit.</font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><a name="REF30923"><b><font size="2" face="Arial">flow
        control</font></b></a>
        <dl>
          <dd><font size="2" face="Arial">Technique for ensuring that a
            transmitting entity, such as a modem, does not overwhelm a receiving
            entity with data. When the buffers on the receiving device are full,
            a message is sent to the sending device to suspend the transmission
            until the data in the buffers has been processed. In IBM networks,
            this technique is called <i>pacing</i>.</font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><a name="REF15620"><b><font size="2" face="Arial">FM</font></b></a>
        <dl>
          <dd><font face="Arial"><strong><font size="2">Frequency modulation</font></strong><font size="2">.
            Modulation technique in which signals of different frequencies
            represent different data values. Compare with <a href="a.html#REF41919"><i>AM</i></a>
            and <a href="p.html#REF29590"><i>PAM</i></a>.
            See also <a href="m.html#REF31911"><i>modulation</i></a>.</font></font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><a name="REF15210"><b><font size="2" face="Arial">FNC</font></b></a>
        <dl>
          <dd><font face="Arial"><strong><font size="2">Federal Networking
            Council</font></strong><font size="2">. Group responsible for
            assessing and coordinating U.S. federal agency networking policies
            and needs.</font></font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><a name="REF29259"><b><font size="2" face="Arial">FOIRL</font></b></a>
        <dl>
          <dd><font face="Arial"><strong><font size="2">Fiber-optic
            interrepeater link</font></strong><font size="2">. Fiber-optic
            signaling methodology based on the IEEE 802.3 fiber-optic
            specification. FOIRL is a precursor of the 10BASE-FL specification,
            which is designed to replace it. See also <a href="nums.html#REF37843"><i>10BASE-FL</i></a>.</font></font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><b><font size="2" face="Arial">format
        indicator 0</font></b>
        <dl>
          <dd><font size="2" face="Arial">See <a href="f.html#REF30959"><i>FID0</i></a>.</font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><b><font size="2" face="Arial">format
        indicator 1</font></b>
        <dl>
          <dd><font size="2" face="Arial">See <a href="f.html#REF36857"><i>FID1</i></a>.</font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><b><font size="2" face="Arial">format
        indicator 2</font></b>
        <dl>
          <dd><font size="2" face="Arial">See <a href="f.html#REF31842"><i>FID2</i></a>.</font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><b><font size="2" face="Arial">format
        indicator 3</font></b>
        <dl>
          <dd><font size="2" face="Arial">See <a href="f.html#REF13855"><i>FID3</i></a>.</font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><b><font size="2" face="Arial">format
        indicator 4</font></b>
        <dl>
          <dd><font size="2" face="Arial">See <a href="f.html#REF23526"><i>FID4</i></a>.</font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><b><font size="2" face="Arial">forward
        channel</font></b>
        <dl>
          <dd><font size="2" face="Arial">Communications path carrying
            information from the call initiator to the called party.</font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><b><font size="2" face="Arial">forward
        delay interval</font></b>
        <dl>
          <dd><font size="2" face="Arial">Amount of time an interface spends
            listening for topology change information after that interface has
            been activated for bridging and before forwarding actually begins.</font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><b><font size="2" face="Arial">forward
        explicit congestion notification</font></b>
        <dl>
          <dd><font size="2" face="Arial">See <a href="f.html#REF33053"><i>FECN</i></a>.</font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><b><font size="2" face="Arial">forwarding</font></b>
        <dl>
          <dd><font size="2" face="Arial">Process of sending a frame toward its
            ultimate destination by way of an internetworking device.</font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><b><font size="2" face="Arial">forwarding
        priority</font></b>
        <dl>
          <dd><font size="2" face="Arial">See <a href="t.html#REF38530"><i>transmit
            priority</i></a>.</font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><b><font size="2" face="Arial">Fourier
        transform</font></b>
        <dl>
          <dd><font size="2" face="Arial">Technique used to evaluate the
            importance of various frequency cycles in a time series pattern.</font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><b><font size="2" face="Arial">four-part
        dotted notation</font></b>
        <dl>
          <dd><font size="2" face="Arial">See <a href="d.html#REF25705"><i>dot
            address</i></a>.</font></dd>
        </dl>
        <p><font face="Arial" size="2"><img border="0" src="../../images/bullet.gif" width="17" height="12"></font><b><font size="2" face="Arial">fractional
        T1</font></b>
        <dl>
          <dd><font size="2" face="Arial">See <a href="c.html#REF25565"><i>channelized