6 Replies Latest reply: Jun 20, 2009 6:39 PM by Scott Morris - CCDE/4xCCIE/2xJNCIE RSS

    Clock Rate command

    KnowledgeAcquirer

      For the clock rate command, are there only specific clock rates for specific Cisco router models?  I had issued the clock rate 128000 at the interface subcommand level for config to try and get the output shown in Example 13-3 on pgs. 415-416 of the CCENT/CCNA ICND1 book.

       

      I got an invalid marker error message when I tried using:  Alburqueque(config-if)# clock rate 128000

       

      However, when I used:  Alburqueque(config-if)#clock rate 64000

      everything worked; i.e.,  1)  no invalid marker error message

                                          2)  sh running-config results in a similar display as shown on pgs. 415-416 of the CCENT/CCNA ICND1 book

                                          3)  sh ip int brief has up/up state for Serial 0 and Serial 1

       

      Thank you,

      KnowledgeAcquirer

        • 1. Re: Clock Rate command
          Scott Morris - CCDE/4xCCIE/2xJNCIE

          It actually depends on your interface type. 

           

          Synchronous interfaces (T1/E1/"serial") will support speeds up to 2M (8M on some models).  Clock rates on these will support 128000 as a valid option.

           

          Asyncronous interfaces on the other hand, will support speeds up to 115200 (think modems!).  So 128000 would not be valid on these.

           

          The "clock rate ?" should show you the valid options for the particular interface you have.

           

          ASYNC:

           

          R3(config-if)#clock rate ?
                  Speed (bits per second)
            300
            1200
            2400
            4800
            9600
            14400
            19200
            28800
            32000
            38400
            48000
            56000
            57600
            64000
            72000
            115200

           

            <300-4000000>    Choose clockrate from list above

           

          R3(config-if)#

           

          SYNC:

           

          R3(config)#int s0/0/0
          R3(config-if)#clock rate ?
                  Speed (bits per second)
            1200
            2400
            4800
            9600
            14400
            19200
            28800
            32000
            38400
            48000
            56000
            57600
            64000
            72000
            115200
            125000
            128000
            148000
            192000
            250000
            256000
            384000
            500000
            512000
            768000
            800000
            1000000
            2000000
            4000000
            5300000
            8000000

           

            <300-8000000>    Choose clockrate from list above

           

          R3(config-if)#

           

          HTH,

           

          Scott

          smorris@internetworkexpert.com

          • 2. Re: Clock Rate command
            Chris

            Scott what would CLN be without your sage and tireless tutelage!

             

            Sincere Thanks,

             

            Chris

            • 3. Re: Clock Rate command
              KnowledgeAcquirer

              Thank you very much :-)

              • 4. Re: Clock Rate command
                Scott Morris - CCDE/4xCCIE/2xJNCIE

                heheheh...  Perhaps a little less lively, although I'm sure there are others who'd step in!  There are 19 people now listed as "experts", so that means you have a good number of folks available to impart their wisdom!

                 

                But thanks!  In the meantime, you're stuck with me! 

                 

                Scott

                • 5. Re: Clock Rate command
                  Chris

                  Scott, as you know, not all networking gear is equally adept or able to perform all tasks; so the CLN "expert" title is a relative term, of which, none of us are your kin...unfortunately!

                   

                  Cheers,

                   

                  Chris

                  • 6. Re: Clock Rate command
                    Scott Morris - CCDE/4xCCIE/2xJNCIE

                    Bah...  While very flattering, I don't believe that!  I'd be willing to be there's some things which you have more experience than I do on.    The fact that I've been around longer (Conwyn and I are both "old farts" in networking years) just means we have different perspectives on things, but not always more experience!

                     

                    There are many others who chime in on different things, and perhaps many others lurking in the woods!  I know I've seen folks the likes of Bruce Caslow around here, and he's quite capable in the technical know-how.  So there's nothing preventing him (or others, no insult to the lurking!) from responding like I do!

                     

                    Again, thanks anyway, I just refuse to believe that it would fall solely to my shoulders. 

                     

                    Scott

                     

                    (2501's still route perfectly fine!  It just depends on exactly what you need to ask of it!)