Delivering the Ccn/figuration to a Router CHAPTER 16
`
`PART IV
`
`To exit ConfigMaker, click the Eile menu, and then click Exit.
`ConfigMakcr is a pretty cool piece of software. Use it to learn more
`about the hardware and software configurations of the various
`routers and devices that Cisco manufactures. It’s not bad at all for
`free.
`
`SEE ALSO
`
`1 ‘rr For rz review ofcazmcairzg fl PC wmale 10 the 7‘aIlteI;.reep1rge 115.
`
`294
`
`

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`295
`
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`296
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`
`PART IV Advanced Configuration and Configuration Tools
`CHAPTEH17 Using a TFIP Server for Router Configuration Storaiier
`
`What is a “E”??? Server?
`
`Saving router configurations to a location other than the router’s
`own NVRAM is a way to protect the time and effort that you have
`put in configuring a particular router. X/Vhen all is said and done the
`router configuration becomes the main factor in how the router
`actually gets its job done. So being able to back up the configuration
`file is a vital part of building some fault tolerance into your internet—
`Working. You already know that when you reconfigure a router you
`must use the Copy command to move the new configuration para-
`meters from the running configuration to the startup configuration
`in NVRANI. There is also a way to copy a running configuration or
`startup configuration to a Computer that is on the network.
`
`Trivi/ll File 'Ii'(zm]‘é7‘ Protocol (TFTP) is a TCP/IP transport protocol
`that can be used to move files from the router to a PC running
`TF1‘? server software. TFTP is actually very similar to the File
`Trzzmfer Protocol (FTP) that is used for uploading and downloading
`files on the Internet (your V/Veb browser supports FTP). FTP
`requires a username and password when you log on to an FTP
`SBKVCI‘.
`
`TFTP doesn’t require a username or password (hence the “trivial”
`notation). All you need to know is the IP address of the computer
`that is running the TFTP server software and you can copy your
`configuration file to the server. You can also use TFTP servers to
`copy a configuration file to your router or upgrade (or change) your
`router IOS image by copying a new IOS file to the routcr_’s flash
`RAM. Because most routers don’t have disk drives, TFTP servers
`provide you with an alternative location for backup files related to
`the router (such as a copy of the configuration or alternative configu-
`rations). Figure 17.1 depicts the different file manipulations that can
`take place between a router and a TFTP server.
`
`So, a TF'I‘P server is a PC that is running TFTP sewer software and
`is accessible on the network. Because neither login nor password is
`required, all you need to know to connect to the TFTP server is its
`IP address.
`
`SEE ALSO
`
`fie F07‘ iIr_fi)77/ratio); on zlring the Copy calm/mm’ wit‘/z m;rfigr11'/rtiartfile.r,.ree pr1geI54.
`
`297
`
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`298
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`
`PART IV Advanced Configuration and Configuration Tools
`
`CHAPTER 17 Using a TFTP Server for Router Configuration Storage
`
`choose an appropriate folder on your Computer where the server
`software can be placed during the download. After the download is
`complete, you can install the Cisco TFTP server software as outlined
`in the next section.
`
`|
`
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`
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`
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`93/NT 4.0 W!"
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`kmsfrning file: am am ayaltmla a.naLhu with Tl-‘FF alien!
`Jofl»Va':re.Aiso, it can be uaedm upgnh mfiwam onC'iscu
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`
`Enetaiiing the Stem ‘TH? Server Software
`You can install the Cisco TFTP server software on a Windows 95 /98
`workstation that is on the same network as the router (this means
`that the router is the default gateway for the TFTP server). For
`example if the routers Ethernet 0 port is configured with the IP
`number 10.16.01, this number should be entered as the workstations
`default gateway. The IP address for the workstation also needs to be
`in the same subnet range as the Ethernet 0 port. Because I’ve divided
`a Class A network (you should be able to tell this by the first Octet of
`the default gateway TP address, if not, go back and take another look
`at Chapter 11) into 14 subnets, and used the first subnet on the
`Ethernet network connected to the router’s E0 port, the range of II’
`addresses’ available would be 10.16.0.1 to 10.32.255.254. Because my
`workstation serves as the TFTP server, I made sure its IP address
`was in this range. I chose 10.16.04 in the TCP/JP Properties dialog
`box, as shown in Figure 17.3.
`
`299
`
`

`
`Installing the Ciscu TFTP Server Software CHAPTER17
`
`PART IV
`
`After you’ve got the IP addressing squared away, you can set up the
`TFTP server software on the workstation. The installation process is
`very straightforward.
`
`Setting up the Cisco TFTP sewer software
`
`1. Use the Vi/indows Explorer to locate the folder where you
`downloaded the Cisco TFTP server software.
`
`. D0uble—cljck the Cisco TFTP icon. The installation program
`for the software will load.
`
`. Click Next after reading the opening Installation. You will be
`asked to choose 21 locationfor the installation of the TFTP
`server software or allow it to be installed to a default folder.
`. Choose a different folder using the Browse button or go with
`the default. Click Next to continue.
`
`. A Default Icons folder will be created for the TFTP program.
`You can choose to have the icon placed in "another folder by
`selecting the folder list provided on this screen. Click Next to
`continue.
`
`. The software will be installed. Click Finish to complete the
`p1‘OC6SS.
`
`‘
`
`. arid ma;"ua"y~avsS?;§n mg.
`‘address in‘ihe TCP/lP__ ."_-
`properiies b0x(see_
`Figure 17.3).
`
`300
`
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`
`PART IV Advanced Configuration and Configuration Tools
`
`CEHAPTER17 Using a TFTP Server for Router Configuration Storage
`
`Now that the software is installed on the Workstation that will serve
`as the TFTP server, you are ready to copy files to and from the
`router. The next section discusses copying a configuration file to the
`TF1‘P server.
`
`fiopyng to the T??? Server
`As you learned previously, you can copy startup configuration files
`from NVRAM or the running configuration file from RAM to the
`TFTP server. For example, let’s say that you have a solid startup
`configuration saved in NVRAM and you want to save it to the
`TF1? server before you make any changes to it. This would enable
`you to restore the original startup configuration file to the router
`from the TFTP server, if your configuration Changes turn out to
`affect network operations negatively
`
`Copying the startup configuration to the TFFP sewer
`1. Start the TFTP server software on the workstation: select the
`fitart menu, choose l_’rograms, and then click Cisco TFTP
`Server. The TFTP Server window will open. The window is
`really just a gray, empty box that displays the IP address of the
`TFTP server (the computer you are running the software on) on
`the Title bar.
`
`. On your router console, enter the Privileged mode using the
`enable command and the enable password.
`
`. At the router prompt, type copy startup-contig tftp, and then
`press Enter.
`
`. You are asked to provide the IP address of the remote host.
`Enter the IP address of the TFTP server (in this case my IP
`address was 10 . 16 . o . 4). Then press the Enter key.
`
`. You will be asked to supply the name of the file you would like
`to write to the server. The default is the routcr’s name followed
`by config (such as cisco2505—config). Press Enter to accept the
`default or enter the name of the configuration file you want to
`copy and then press Enter.
`. You will be asked to confirm the procedure (see Figure 17.4).
`Press Enter to confirm (if you don’t want to confirm, type n for
`no and you will be returned to the Privileged prompt).
`
`301
`
`

`
`Copying from the TFTP Server CHAPTEH17
`
`PART IV
`
`.1::cn25lBSflcnpy star-tup—cnn£ig tit]!
`enact! hunt I]? lfl.16.fl_4
`anu Inf cunfiguratinn Pile tn ux-‘Ike [ci:I:u25BS-ccInf5'J'l
`rite file: r:i:n;u25D5—curnfg un lmnt
`iPI.1fi.EL‘l7 lcunfin-nlfl
`
`The file will be written to the TFTP server. A prompt reading
`Writing router‘ name-config. H [OK] means that the copy was a suc-
`cess. If you return to the TFTP Server Workstation and look at the
`server window, you will find that a record of the copy job has been
`recorded, as shown in Figure 17.5. The TFTP server window also
`confirms that the copy job was a success.
`
`You can also copy the 111nning—config from RAM using the proce-
`dure outlined. The only difference is that the command in step 3
`would read copy running~config tftp.
`
`Sewing from the FR”? Server
`
`The reverse 0pcrati0n—copying a file from the TFTP server to the
`router—is as straightforward as the process outlined in the previous
`section. You can copy a co11fig11ration file from the TFTP server into
`the router’s NVRAM or you can copy the configuration Erorn the
`server directly into RAM as a new run11ing—configuration. If you
`copy the file into NVRAM it not only becomes the new running
`configuration for the router but it also will be the startup configura~
`tion when you reboot the router. Lets take a look at how to copy the
`
`302
`
`

`
`PART Iv Advanced Configuration and Configuration Tools
`
`cHApTER 17 Using a TFTP Server for Router Configuratio’niVStorage
`
`configuration file from the server into the NVRAM where it
`becomes the new startup configuration for the router.
`
`Copying the startup configuration to router
`1. Start the TFTP server software on the sewer Workstation.
`
`2. On your router console, enter the Privileged mode using the
`enable command and the enable password.
`
`. At the router prompt, type copy tftp startup-config, and then
`press Enter.
`
`You are asked to provide the IP address of the remote host.
`Enter the II’ address of the TFTP server (in this case my IP
`address was 10.16.0.4). Then press the Enter key.
`
`You are asked to provide the name of the configuration file on
`the TFTP server you want to copy. Type the name at the
`prompt (if you use the default name when you copied the file to
`the server, you don’t need to enter a new name). Press Enter to
`continue.
`
`You will be asked to confirm the procedure (see Figure 17.6).
`Press Enter to confirm.
`
`1:|:o2§B5llv;n11y lift ctartu -cnnfig
`= ddrnlts of rlznukn mat
`[ZS .255.Z55.Z§5l'[1FJ.16.D.4.
`arm: oF configuration file EI:1sx:o2!nfl5-conFg]T
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`.-m£igu.~a Inring :::l:to2'Kfl5-cnnfg frnn 1o.1s.n.-17 [mmfh-n1
`
`The file will be loaded to the router and will become the active con-
`
`Again you will receive an
`figuration (and will he saved in
`[OK] message on the router that the procedure was a success. You can
`return to the TFTP server where the process will also he confirmed
`as a success.
`
`303
`
`

`
`leading a New IOS from the TFTP Server EHAPTER 17
`
`PART {V
`
`Laadeg a New Q3 train the 3“F°E”P Server
`
`As you can see, copying to and from the TFTP server is a pretty easy
`process (when you compare it to creating IP subnets or doing some
`of the other configuration chores required by the router). You can
`also use the TFTP server to copy various versions of the IOS to the
`Flash RAM on the router. This makes it very easy to update the
`operating system on the router.
`
`Cisco is constantly fine—tuning the IOS available for their routers. A
`number of different release versions are available. At the time this
`
`book was being written a new release, version 12, became available.
`Of course, as with any new operating system, bugs are found and
`fixes are programmed so a number of service releases are also made
`available for new IOS versions. In Cisco’s case, upgrade Versions of
`even what would be considered an older IOS such as 11 are still
`
`being fine—tuned, as well. You can View all the most recent IOS ver-
`sions available on the Ciseo Web site at www. cj.sco.com.
`_
`‘
`To download operating system images (files), you must have the
`appropriate service agreement with the Ciseo reseller who sold you
`your router. A Valid service contract number is required and you
`must register on the Cisco site to download IOS files. Figure 17.7
`shows the Web page that provides the links to the various IOS
`images. This page also provides a convenient IOS planner that
`enables you to choose new IOS versions by your router (for example,
`I would click my Cisco 2505 router and only the IOS images appro~
`priate for that model of router would appear on the Planner page.
`
`To load a new IOS into a router’s Flash RANI, download an appro-
`priate IOS image from the Cisco Web site (if you purchased an IOS
`update from your Cisco reseller, you might also have the IOS files on
`a CD). Place the IOS file in the TF1‘P server's root folder. The
`default for this folder is C:\Cisco Syste1ns\Cis«‘:o TFTP Server and
`you can use the VV1ndows Explorer to copy or move the file to the
`appropriate folder.
`
`fl En!er(where the IP V‘ 1
`__
`address ismat Of'th'e'
`1
`i
`I
`server/workstation). W0"
`gtP‘at”a‘E:ST'tF"$d
`Wme pmess again.
`
`304
`
`

`
`PARTIV Advanced Configuration and Configuration Tools
`
`CHAPTER 17 Using a TFTP Server for Router Configuration Storage
`
`mm r_v_m-nuiwrtromiiiql
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`Ourxmw Cisco IOS Pladner alloivs you more flnxiéxility to browse foryour prafcnréd soflivain. No longer are you limited toy
`sceingjust on: major release at A time, or forced to make choices in a certain order. You can now View all major releases, all
`platforms. and all sofiware features Rom ix single interface. Choosing a plalfonn, a xnainlenance reluaée; or sofiware feature wan
`autontarically limit the other menu choice: based on your selecfion, unlilyou arrive at your preferred solhvatt,
`I
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`i CCC Siollvaaxi-.
`
`Now you are ready to copy the new 103 into the routers Flash. Be
`advised that this version of the IOS will replace the previous version.
`You can choose to not have the Flash RAIVI erased during the copy
`process, but that means you will have multiple copies of the IOS in
`Flash; in the case of the 2505 router with only 8MB of Flash, there is
`only enough room for one IOS image, anyhow.
`
`After the IOS file is on the TFTP Server, you are ready to begin the
`process that will move the IOS file onto the router.
`
`Copying a New IDS to the Homer's Flash RAM
`1. Start the TFTP server software on the server workstation.
`
`2. On your router console, enter the Privileged mode using the
`enable command and the enable password.
`
`3. At the router prompt, type copy tftp flash, and then press
`Enter.
`
`4. You are notified that the router will proceed with the copy, but
`that router functions will be stopped while the IOS image is
`updated. To proceed, press Enter.
`
`305
`
`

`
`306
`
`

`
`PART IV Advanced Configuration and Configuration Tools
`
`CHAPTER 17 Using a TFTP Server for Router Configuration Storage
`
`The current 108 image will be erased and replaced by the new IOS
`image. A series of exclamation points appear on the router as the
`process takes place. This process may take a couple of minutes
`because the IDS images can be quite large (the 11.2 IOS is over
`6MB). If you take a peek at the Cisco TFTP server window, a series
`of number symbols (#) repeat across the screen as the process takes
`place.
`
`The router will reboot after the new IOS file is copied. You can now
`press Enter and enter the console password (if required) to place
`yourself at the user prompt. To check your new IOS image, type show
`flash at the prompt, and then press Enter. The new IOS image (the
`filename you entered in step 6) should now reside in the router’s
`Flash.
`
`You can also copy the current IOS image to a TFTP server if you
`, want. This gives you a backup if the Flash RAM on the router goes
`bad or you just like having a copy of the IOS safely filed away in a
`secondary location. The command at the Privileged prompt would
`be copy flash tftp. You then provide the IP address of the server
`and other information as requested in the steps already discussed.
`
`TFTP servers make an excellent repository for alternative configura—
`tion files and IOS updates. They supply you with the backup storage
`space that the router itself doesn’t have.
`
`307
`
`

`
`308
`
`

`
`PART IV Advanced Configuration and Configuration Tools
`
`CHAPTER 13 Basic Router Troubleshooting
`
`“tratahéesheetng Hardware Presents
`
`Although the subject of troubleshooting your router connections and
`configurations would certainly fill an entire book (or books), it prob-
`ably makes sense to finish up a primer book on internetworking and
`Cisco routers with a basic overview of troubleshooting techniques.
`Hardware problems that you could face can include a failed router
`interface controller, making an interface or interfaces inoperable, or
`a router that has just rolled over and died completely.
`
`Other problems on your internetwork will most likely boil down to
`two categories such as physical connection problems and router con-
`figuration problems. Some physical connection problems you have
`control over such as a bad router serial cable or a hardware problem
`with a hub or a stretch of network cabling. Other events such as an
`out—of—control]eep Cherokee crashing into the phone company’s
`switching equipment is just a little beyond your control. Some hard-
`ware problems you can fix; others you just have to sit and wait
`(which is difficult when your users can’t access the resources that
`they need to do their jobs).
`
`As far as configuration problems go, some adjustments to a configu-
`ration might be necessary if there are radical changes to the network
`topology (such as a downed connection). In other cases, your original
`configuration might not be up snuff and you need to edit it to
`resolve issues that are affecting the internetwork negatively. You will
`look at configuration issues a11d the troubleshooting of specific pro-
`tocols later in this chapter.
`
`Eiouter Problems
`
`Router hardware problems can revolve around interface controllers,
`RAM modules, the routers processor, and even the router’s fan. And
`although it might sound silly, the first thing you should check on a
`router that is down is whether the router has been turned off or the
`
`power cord has been kicked out of the wall socket.
`
`You learned the basics of router interfaces in Chapter 6,
`“Understanding Router Interfaces.” The various network and WAN
`interfaces on the router are each connected to a controller. The
`interface controller is either hardwired to the router’s motherboard
`
`309
`
`

`
`Troubleshooting Hardware Problems CHAPTER 18
`
`PART IV
`
`(as is the case with the 2500 series) or contained on the interface
`V ard that you placed in one of the slots available on the router (as is
`the case with Cisco’s higher end routers like the 4500 series).
`
`One way to check a particular interface on the router is using the
`Show interfaces command. If the interface is up and the line proto-
`col is up (asshowii in Figure 18.1), you don’t have a problem with
`that interface. If the interface controller no longer functions, the
`interface Won’t register as an available interface when you use the
`show interfaces command. If the interface is up and the line proto—
`C01 is down, your problem is a configuration issue, not a hardware
`problem.
`
`II=in§ huh I!
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`nescrjptinn: cnnnzctud en Ri:lIr.-I'rIatLfiN
`Internal: mlrlrzss in 139.10.32.1/19
`NIU 1563 hvtnu. EH 13353 Kbit. D11‘!
`IDED nsuv. xuly 255/255.
`luau! 1/255
`Enauysulntinli
`flIll‘fl,
`lnaphaok nut sat, kcepalive uek (19 sec)
`IIBP typo:
`IIRYI1. NIP Iinauut B4:BB:BB
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`5 ninllte nutyut A--nti: 0 bit:/sac, E paclrets/sun
`8 packets input, B bytes, 3 nu buffer
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`LOP Open
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`Last input:
`flB=B|]:B3. output Efi:Bfl:B1, output hung navzt
`Last clearing at "sham into:-Face" onuntors not/or
`rnpuemmue: a/75/a (ciza/nax/drape); Total outjmt amps: u
`Quanezmg flzvatea : usigluted Fair
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`He: went Cnnvzl-xatinns Ia/B (allncatud/max allncatml)
`—n
`
`1041:! 1/255
`
`You can also check the controllers on your router. The show con-
`trollers command provides statistics for interface controller cards.
`Figure 18.2 shows the results of the show controller éthernet
`command.
`
`Another component on the router that is of vital importance is the
`router’s fan (it’s one of the cheapest parts but also one of the most
`important). If the fan doesn’t work, the router will overheat (just like
`a PC with a broken fan). lt will reboot. So, if you have a router that
`seems to reboot after only being on for a short period of time, power
`up the router and listen carefully to see if the fan is Working.
`
`310
`
`

`
`PART IV Advanced Configuration and Configuration Tools
`
`CHAPTER1l3 Basic Router Troubleshooting
`
`(Some of the high—end Cisco routers actually have complex cooling
`systems and also enable you to monitor the temperature of the
`
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`
`In cases where the router crashes, it can be tough to determine if the
`problem was hardware— or s0ftware—related. You can use the show
`stacks command to retrieve error messages that were saved by the
`ROM monitor at the time of the crash. (Cisco technical support rep-
`resentatives can use the show stacks information to pinpoint the soft-
`ware or hardware problem that caused the crash).
`
`Besides the physical failure of router components, you might also run
`into situations where the router doesn’t have enough RAM (or
`processor speed) to really handle all the traffic that you have flowing
`through it. You might need to add additional routers to the internet—
`work to lighten the load or upgrade existing router hardware compo-
`nents (such as RAND. In some cases you might want to upgrade from
`the existing router to a higher—end router.
`
`One way that network administrators identify bottlenecks on their
`networks (a Izottlenec/e is a device that is slowing network traffic) is to
`use some type of network management software package that allows
`the monitoring of devices, protocols, and other aspects of the net-
`work and enables you to View the current health of your internet—
`work. CiscoWorks is an example of a network management software
`
`311
`
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`

`
`W-WT W Advanced Configuration and Configuration Tools
`
`CHAFTER18 Basic Router Troubleshooting
`
`internetwork by providing redundant connections (backup connec-
`tions) between certain routers. For example, you might have 21 Frame
`Relay connection between two routers. As a backup, you configure
`the router so that it can also connect to the remote router using a
`dial—up connection over a modem if necessary. The modem line
`won’t give you the speed that the Fra1ne—Relay connection will, but if
`you have to move time-sensitive data, you at least have a backup
`route for the packets.
`
`Cabling Pmhiems
`
`Connectivity problems on a LAN related to physical cabling on the
`LAN can be due to shorts, breaks, and other problems. In cases
`where physical connections (that you have control over) are suspect,
`a Variety of tools are available for checking cabling ranging from
`voltmeters to time domain reflectometers (TDR).
`
`A digital voltmeter is a simple device that can be connected to a cable
`and test the cable for a break or a short. Basically, the voltmeter can
`tell you if the cable is bad or not and whether you are looking at a
`short or break. If the cable has a short, replace it. If there is a break,
`you must trace the cable (have fun standing on a ladder with your
`head stuck up in the drop-ceiling) to find where the break has
`occurred.
`
`A TDR is a more sophisticated device that can diagnose shorts and
`breaks in a cable but it can also provide you with information on
`where the short or break exists on the cable. The TDR actually
`emits short pulses down the cable and is able to use a timing mecha-
`nism that estimates the distance that the pulse has traveled.
`
`Network cabling is always suspect. People move furniture and dis-
`rupt cable connections, a leaky roof allows cabling in the ceiling to
`become soaked with Water (sometimes leading to shorts)——a1l sorts of
`weird things can happen to cables that sever the connection that they
`were providing. Always check cables first. Then move on to some of
`the other devices you’ve discussed.
`SEE ALSO
`
`37“ For (I review ofnetwark milling, ma page 17.
`
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`
`

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`314
`
`

`
`PABTIV Advanced Configuration and Configuration Tools
`
`CHAPTER 18 Basic Router Troubleshooting
`
`The show interfaces ethernet [interface number] command
`enables you to View statistics related to a particular Ethernet inter~
`face. Figure 18.3 shows the results of this command on an Ethernet
`0 interface on a Cisco 2505 router.
`
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`Although the statistics provided might seem rather cryptic at first
`examiiiadon, they actually provide a great deal of information that
`can help you troubleshoot problems related to an Ethernet interface.
`Some of these statistics also provide insight into the use of other
`hardware resources on the router such as RAM. The list diat follows
`
`highlights some of the statistics found in response to the show
`interfaces ethernet [interface number] Command.
`
`- Ethernet 0 is Up, Line Protocol is Up—This lets you know that
`the interface is active and that the Ethernet protocols believe
`that the line is usable. If the interface is down, check the LAN
`connection to the interface. You can also try to bring up the
`interface in the Configuration mode (if the LAN connection is
`okay). Enter the configuration-if mode for the interface and
`'‘bounce’’ the interface. Use the shut command (to down the
`interface), and then use the no shut command to up the inter-
`face. This might bring the interface back up.
`Hardware Address—This is the hexadecimal MAC address for
`the interface.
`
`Internet Address—This is the IP address and subnet mask
`
`assigned to the interface (you will learn IP addressing in the
`“Troubleshooting TCP/IP” section).
`
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`
`

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`
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`
`PART IV Advanced Configuration and Configuration Tools
`
`CHAPTER 18 Basic Router Troubleshooting
`
`The command to View the statistics related to a Token Ring interface
`is show interfaces tokenring [interface number]. And as with the
`show interfaces command on Ethernet interfaces, this command
`shows the status of the interface and information on the hardware
`and protocol addresses of the interface as well as information on the
`interfaces reliability. A number of the parameters shown in the sta-
`tistics are the same as those shownfor an Ethernet port (such as
`Hardware Address, Internet Address, MTU, BW, and Rely). Other
`settings have to do with '1Z)lcen Ring LAN functionality such as ring
`speed.
`
`a Token Ring is Up—This lets you know that the interface is Cur-
`rently active. if the interface is down, you can try to bounce the
`interface in the configuratjon—if mode to get it back online.
`
`Hardware Address—This is the hexadecimal MAC address for
`the interface.
`
`Internet Address——This is the IP address and subnet mask
`
`assigned to the interface (you will learn IP addressing in the
`“Troubleshooting TCP/IP” section).
`
`MTU-This is the maximum iiansmission unit for the interface
`in bytes.
`BW This is the bandwidth for die interface in lcilobits/second.
`
`Rely—~This is a measurement of the reliability of the line with
`255/255 being 100 percent reliable. This measurement is aVer—
`aged for the interface over a period of five minutes.
`Load——This measures the current load on the interface. The
`
`measurement 255/255 would be a totally saturated interface and
`again means that you might have too large of a Token Ring
`LAN being serviced by the one interface on the router.
`
`Ring Speed This is setting for the speed of the Token Ring
`LAN that the router is connected to. All devices on the Token
`
`Ring network, including the router, must be using the same ring
`speed (either 4Mbps or 16Mbps). Any mismatches will result in
`an interruption in the flow of data. To check the ring speed set
`on the router use the show running~config command. Ifyou
`need to reset the ring speed enter the config—if mode on the
`router console for the interface. Then use the ring —speed com—
`mand to reset the ring speed.
`
`317
`
`

`
`Troubleshooting WAN Interfaces CHAPTEB13
`
`PART IV
`
`u Restarts—On Token Ring Interfaces this value should always be
`0. If it is other than 0, the interface has been restarted because of
`some problem on the Token Ring LAN.
`
`Troubleshooting Token Ring interfaces on routers requires a very
`good understanding of how Token Ring LANs operate. Problems
`such as congested rings, for example, require that you further seg-
`me