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Clock rate readings on a serial interface

I have a few 2620 with serial interface S0/0. The interfaces are DTE and hence receiving clock rate from the DCE devices. The DCE devices are property of the WAN provider. What I'd like to do is finding out what exactly is the clock rate that the routers received from the DCE devices. I'm doing this cause at the moment those routers are running FR and I (and the users) noticed application slowness when the link is congested. When congested, I don't see the traffic reached CIR rate (about 80% CIR) let alone the Access rate. I don't see BECN and FECN neither. I'm investigatting whether the carrier actually provides the appropriate clock rate before spending time in flooding the WAN links (by using multiple FTPs) and timed the transfer. If you know of a method/application where I can test for the integrity of the lines please let me know. This would be greatly appreciated.

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Re: Clock rate readings on a serial interface

I believe that the 'show controlllers' command in some of the recent IOS releases like 12.2.5 display the clock rate received from the DCE.See if the version that you are running gives you this information. Since you do not have control over the DCE the only other way that I could think of is to check the clock signal using an Oscilloscope. Based on the physical standard (V.35, RS 232) you can verify the clock signal between GND and the respective PINS. Or else you can use a frequency counter as well to see if they detect the signals and calculate the frequency.

1 REPLY
Bronze

Re: Clock rate readings on a serial interface

I believe that the 'show controlllers' command in some of the recent IOS releases like 12.2.5 display the clock rate received from the DCE.See if the version that you are running gives you this information. Since you do not have control over the DCE the only other way that I could think of is to check the clock signal using an Oscilloscope. Based on the physical standard (V.35, RS 232) you can verify the clock signal between GND and the respective PINS. Or else you can use a frequency counter as well to see if they detect the signals and calculate the frequency.

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