Broadband network

Hi everybody

Hope that my question is on the right forum...

So, I'm trying to understand how functions the long-distance networks! I'm still reading some tutorial but I'm occurs some problem to find a right and good global visions...

Here is a example :
There are three site A, B and C. The distance between A and B are short and we use CWDM, on the other hand the site C is far away and use DWDM.
These sites A, B and C use Gigabit Ethernet and they should communicate together.

First questions:
-I want to know how the Ethernet frames will be transported within WDM?
-Are the frames encapsulated in WDM frames? therefore we need converters??
-The Ethernet is distance limited but he runs with WDM? How to do that?

Second questions:
-There are some multiplexing like: Time (TDM), Wave (WDM) or Code (CDM). My question is: How to know which of these techniques do we have to implement or which are the characteristics of those?

Thank you in advances for your answer?
I will be grateful if someone could give me links on good tutorials or good reference of books (not too large  ;))

Quote:I know all well what relates to the LAN Networks and I must start to study the WAN Networks (Broadband Network) and there, nothing goes any more  ???

Thx