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Synchronization of DWDM

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zathe...@gmail.com

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Nov 29, 2008, 12:10:52 PM11/29/08
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Sir,

Can you please tell me why DWDM is not synchronous? Does it depends on
data rate?

Satheesh

Michelot

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Nov 29, 2008, 1:34:53 PM11/29/08
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Bonsoir Satheesh,

> Can you please tell me why DWDM is not synchronous? Does it depends on
> data rate?

Huub will correct or complete my reply.


Take care of the word "synchronous", there are many meanings.

If you refer to G.825 you can see that a synchronous interface
provides an output signal with frequency traceable to a PRC (in normal
condition).

According to that definition, SDH is synchronous and OTN is
asynchronous.

If DWDM is made of SDH wavelengths, you are in a synchronous network.
Il the DWDM is made of OTN wavelengths the network is asynchronous.
But you can mix these clients in the optical layer network.

Best regards,
Michelot

zathe...@gmail.com

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Nov 30, 2008, 12:08:28 AM11/30/08
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So it means the DWDM can be synchronous OR not depending up on whether
the client signal is synchronous OR not respectively. Am I right sir?

Huub van Helvoort

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Nov 30, 2008, 5:26:07 AM11/30/08
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Hi Satheesh,

You asked:

> Can you please tell me why DWDM is not synchronous? Does it depends on
> data rate?

As (D)WDM is a wavelength multiplex, optical signals are transported
and switched, so there is no need to synchronise.

Only at the tributary ports where client signals are mapped
into the optical signals the mapping can be synchronous or
a-synchronous.

Cheers, Huub.

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Huub van Helvoort

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Nov 30, 2008, 5:28:02 AM11/30/08
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Bonjour Michelot,

You replied:

>> Can you please tell me why DWDM is not synchronous? Does it depends on
>> data rate?
>
> Huub will correct or complete my reply.

;-)

> Take care of the word "synchronous", there are many meanings.
>
> If you refer to G.825 you can see that a synchronous interface
> provides an output signal with frequency traceable to a PRC (in normal
> condition).
>
> According to that definition, SDH is synchronous and OTN is
> asynchronous.

Indeed, see my earlier reply also.

> If DWDM is made of SDH wavelengths, you are in a synchronous network.
> Il the DWDM is made of OTN wavelengths the network is asynchronous.
> But you can mix these clients in the optical layer network.

Agree.

Huub van Helvoort

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Nov 30, 2008, 5:39:56 AM11/30/08
to
Hello Sateesh,

You replied:

> So it means the DWDM can be synchronous OR not depending up on whether
> the client signal is synchronous OR not respectively. Am I right sir?

It can even be both, because ift can be synchronous with some
client signals and a-synchronous with other client signals.
Because they come from different networks.

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