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Home > Archive > CCNA > October 2001 > can't set clockrate 56000 on 2514 router
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can't set clockrate 56000 on 2514 router
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| i'm practicing setting up 5 brand new cisco lab semister 1 routers from scratch, which include 1 2514 router and 4 2500 routers.
right now i'm just working on getting Lab-A and Lab-B configured. all are connected through the serial ports from S0 to S1 and are powered on.
Lab-A is the 2514 with 1 serial 0 port
Lab-B is a 2500 with 2 serial ports (s0, s1)
ON LAB-A:
when i try to set the clockrate to 56000, config t, interface s0, it says something about "this can only be done on a DCE". it DOES let me give it an ip address and subnet mask and no shutdown, but not the clockrate. i've done this at my school lab and it went pretty smooth.
AND ON Lab-B:
i set up the 2 serial interfaces with the correct IP addresses, subnet masks, no shutdown, etc., but when i go back and "show config", it shows that there isn't anything set.
running version 12.0(10)
any ideas?? | |
| sallama18 2001-10-23, 11:40 pm |
| First, use sh controller command to see interface either dce or dte.Only DCE interface you can use clock rate command. | |
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| i wasn't aware that you had to set the s0 interface to dce. i thought that the command "clockrate 56000" made it the dce. | |
| doctorcisco 2001-10-24, 6:30 am |
| quote:
Originally posted by lew
i wasn't aware that you had to set the s0 interface to dce. i thought that the command "clockrate 56000" made it the dce.
The interface is DCE if the DCE end of the crossover cable is attached to it. show controller s 0 will tell you what kind of cable is attached.
Assuming you have a crossover cable attached, you need to:
1) Put the clockrate command on the other router, or
2) Turn the cable around so that the DCE end is attached to your 2514.
On Cisco crossover cables, and all the no-name cables I've seen, the DCE and DTE ends are clearly marked on the connectors.
HTH,
doctorcisco | |
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| not meaning to sound ignorant, but.....
there is a big blue serial cable coming out of S0 on Lab-A and also a big blue serial cable coming out of S1 on Lab-B, and they are connected in the middle through another connector-type.
are you saying that one of those cables probalby just need to be flip-flopped?? | |
| depamo 2001-10-24, 9:38 pm |
| You are using a DTE/DCE connector to connect your two router's serial ports. If you want to see which is which, on the cable you will see an identifier that tells you what cable you have on each end. If they are plugged together you have one of each.
eg.. on the RS-449, on the top of the connector you will see on the HD-60 side, RS-449 DTE or DCE. On the side that has the HD-60 DCE connected to the router port, you put a clockrate command on that serial port and do not put one on the other side. Only one router provides line clocking.
I usually remeber this since DCE has a 'C' in it, that reminds me to 'clock' this side. In most pratice you will hardly ever use this cable, mostly you will get external clocking from another device and use a DTE cable.
To see the speeds that you can use, in interface configuration mode, type in clockrate ? and hit enter, should show you which values are available. | |
| sallama18 2001-10-25, 12:29 pm |
| my brain is confused.before setting clock rate can ý see which interface dce or dte without looking attached cable and only use sh controller s0 command.Or once set clock rate endly use this command.I am using only router simulator no real router and sory for my english. | |
| dmaftei 2001-10-25, 6:47 pm |
| quote:
Originally posted by lew
i wasn't aware that you had to set the s0 interface to dce. i thought that the command "clockrate 56000" made it the dce.
A serial interface becomes DCE or DTE depending on the connector you plug in. The interface (or should I say the controller?) "reads" the pinout on the connector, and "learns" the type of the connector. That's how the interface (or should I say the controller?) decides what to become: DCE or DTE.
With the clock rate command you set the speed the of the line. Since both ends of a line should agree on one speed, it makes sense to have only one end clock the line. By convention, I suppose, it was decided that end to be the DCE. | |
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| thank you SO MUCH!!
i looked at the cables and there is a white tag on each end...one says DCE, one says DTE. alls i had to do was switch the cable.
i realize that i could have just set the clock rate on the other router, but i'm "trying" to help setup a new Cisco lab for teaching, and they want their interfaces set up a certain way.
thanks again!! |
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