On Jun 25, 2008, at 6:59 AM, Freek Dijkstra wrote:
John Vollbrecht wrote:
So what exactly is an adaptation.
See also my mail yesterday.
Loosly, adaptation is the encapsulation of one data layer into another data layer.
A de-adaptation is the extraction of data from that lower layer (which also terminates the lower layer path).
Formally (G.800):
The adaptation source function is a labelling and encoding entity that takes one or more client communications passing through its client facing input port(s), and combines them into instances of adapted information. The adaptation source function also adds sufficient labelling in order to distinguish each client communication from all others within the scope of the access point to which the adaptation source is bound. The instances of adapted information are passed through the server facing port.
For example, and OTN port might convert things to SONET, Ethernet, and other line protocols. Is this adaptation?
Yes, if "things" is a higher layer than SONET or Ethernet.
I think that I understand what you are saying - that a link has a single stream on it and that single stream can be adapted to some other layer. However, in multiplexed networks like DCN a link can carry many streams and each stream can be adapted differently. In fact, in an ete circuit there may be several links and each link may do a different adaptation. How does the topology describe something like this? John