Hi Guilherme-

These examples don't speak to path selection constraints or any particular transport framing constraints.  This being said, I did assume that these STPs were compatible (as I wasn't trying to show transport layer function - just path object manipulation)   Further, I did not state whether  A>B meant that these were adjacent STPs in the topology - in my mind I assumed the A>B was assumed to be a loose hop.  I tried to just state some very simple nomenclature for describing path objects, and then make some simple statement about how they can be decomposed and re-combined.   A and M (for example) could be very differnet types of STPs, how or why they ended up in the path object wasn't germaine to this issue (IMO).

Given A>M, and N>Z, concatenating these two paths requires that M and N be examined.  If they are not equivalent topologically then the concatenation A>M>N>Z would imply/require some sort of path construction from M to N was necessary.  That path selection would [magically] address your concerns. (:-)   If they did turn out to be equivalent points, then the adaptation you ask about would presumably have been done between A and M or between N and Z.  Again, I wasn't trying to define how the path was selected, just how to manipulate it after the fact..  

Hope this helps (and thanks for reading it close enough to ask the questions - valid questions.) 
Regard
Jerry

Guilherme Fernandes wrote: 
Wouldn't it be possible for A>M to end be terminated at a different layer
(L1) than the entry layer L2 for M>Z, and M not have the adaptation
function
L1->L2?

In that case, the first implication does not hold, and would need
Concatenation to be conditional.

(Sorry if this doesn't follow NSI terminology)

Guilherme

  
Can I propose some connection decomposition and manipulation
semantics?   Try these:

Definition:  A Service Termination/Transit Point  "STP" identifies a
location in the topology.   STPs primarily denote a lowest level
component of the topology where a service instance may begin, end, or
transit.   An STP may also identify a higher level topological construct
where a service instance may begin, end, or transit.   In the case of a
higher level construct, the service instance may touch any sub-component
to meet the termination or transit constraint.

Definition:  Given STPs A and Z,  "A>Z" denotes a unidirectional Path
beginning at A and ending at Z;

Rule 1:  Equivalence:    Given two STPs J and K,    If J==K ("J is
topologically equivalent to K"), then K==J, and both identify the same
location (object) in the topology.

Rule 2: Concatenation:    Given STPs A,M,N,,Z, a Connection C1:=(A>M),
and a Connection C2:=(N>Z),
                    then   C1:C2 == (A>M):(N>Z) == (A>M>N>Z)       "C1
concatenated with C2 is equivalent to ..."

Implications:

-  If Connection A>M exists, and a Connection M>Z exists,  Then by
concatenation a Connection A>M>Z exists, and by implication A>Z exists.
-  Given J==K, then A>J == A>K;   and  (J>K)==J==K;
- Given STPs A, M, N, and Z,   If M==N, then (A>M):(N>Z) == A>M>N>Z ==
A>M>Z ==A>N>Z;

Thoughts?
Jerry



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