why clock rate command on only one side??

[singhankit685]

in point to point link why we use clock rate command on only one side of the link i.e dce side ??

if clock rate generates speed then what will generate the speed on the dte side for the packets to get back to other end ??

[Peter Paluch]

Hi,

The DCE/DTE is a specific way of constructing serial data connections between two devices. It is by design that the DCE device generates the clock, and this clocking signal is carried over designated wires in the cable to the DTE device. The DTE device can sense the clocking signal, and with each clock tick, it is allowed to read in one bit on the Rx wire, and transmit one bit through the Tx wire. DCE interface operates in the same way. As a result, the data transmission speed of DCE and DTE interfaces is precisely the same.

Best regards,
Peter

[singhankit685]

sir i meant to ask what generates the speed from dte side?? how data travels from dte side back to dce side??

[Peter Paluch]

Hi,

The DTE side listens to the clock signal transmitted from the DCE side, and adapts to it. Remember - there are extra wires in the serial connection used only to carry the clocking signal from the DCE to the DTE; data are carried over another wires in the cable. DTE does not have its own clock; instead, it completely follows the clock of the DCE side. We could say that in terms of clocking, the DCE is the master, and the DTE is the slave.

Would this help a little more?

Best regards,
Peter

[singhankit685]

still i am unable to understand peter...is this a service provider track concept?? will it be in detail in that track?? i am studying ccnp routing and switching......

[Peter Paluch]

Hi,

Serial interfaces are covered both in Routing&Switching and in Service Provider tracks.

Maybe there is a language barrier preventing me from understanding what your question really is, and preventing you from understanding what I am trying to explain. Usually, in this cases, it could be helpful if you tried to come up with a simple step-by-step scenario that would show how you understand and explain the issue to yourself, and then I can try to correct you and fill in the gaps. Would you be willing to explain your question in the form of such a step-by-step scenario? The more description you put into explaining your understanding and your questions, the better we can understand your doubts.

Best regards,
Peter

[Joseph W. Doherty]

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Posting

You only need clock sourced on one side of the connection, because both sides use it.  By convention/standard, it's sourced on the DCE side.

Understand, both sides have their own internal clocks, but as clocks tend to keep time differently (i.e. usually one clock will run a bit faster or slower than other clock), one side "shares" it's clock with the other, so both sides can stay in sync.

NB: the clock signal is used to "know" when to "look" at a data signal to determine its value.

[singhankit685]

 @joseph thanks!! finally understood something .....but as far as i kw clocking is done to make a signal stronger so that it can travel a long distance...am i right??   

[Joseph W. Doherty]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages wha2tsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

Not that I'm aware of.  Again, it's so receiver knows when to "look" at data stream to correctly recover bit stream as intended by sender.

[Peter Paluch]

Hi,

clocking is done to make a signal stronger so that it can travel a long distance

No, certainly not. Making a signal stronger is called amplification, sometimes regeneration. Clocking is done to make sure that the time that the duration of a single bit is the same on the sender and the receiver, so that when the sender sends a sequence of bits, the receiver can properly tell the individual bits apart and process them.

Best regards,
Peter