| Author |
S0 Change state to up then down
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| ahpama 2001-10-21, 5:46 pm |
| Hi,
I am configuring my CISCO 2500 but when I issue a no shutdown command on my S0 it changes the state to up but after 10-20 seconds it changes its state to down. why?
thanks. | |
| ahpama 2001-10-21, 5:49 pm |
| btw....
I am connecting it back to back to my other CISCO 4000 router. Thanks a lot.
TIA.  | |
| supergoku0 2001-10-22, 12:07 am |
| Ahpama,
You may try adding the command "clock 64000" under the serial interface of one router, with this that router becomes DCE and the other being DCE, also make sure the encapsulation type of both interface are the same.
However I saw one occassion that the serial UP / DOWN problem was caused by the incompatibily of DTU's attached to both routers, after making both ends of DTU's of same brand the problem was solved.
Goku | |
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| Yep, by connecting back to back, you will not have a clock source unless you issue the command "clock rate 64000" on one of the router's serial(if you're connecting the serial). It actually acts as a CSU/DSU
from the service provider by giving you a clock source(clocking). | |
| ahpama 2001-10-22, 2:21 am |
| thanks a lot... i really appreciate your response.
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| dmaftei 2001-10-22, 7:49 pm |
| Once you know one is DTE and the other is DCE, make sure you have a DTE/DCE cable too. | |
| depamo 2001-10-22, 8:53 pm |
| Chances are that the keepalive timer is set to this interval. Usually 10 seconds, you can see it when you do a show interface command. Time is in seconds.
When you no shut an interface, it will come up for the duration of the keepalive timer if there is some type of properly connected cable. Once the timer expires, the port will go down again. You can test this out with the no keepalive command in interface configuration mode. Port will stay up.
This is common with the back to back cable without the clockrate command being entered. Others hit it right on the nose. |
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