Jerry Sobieski wrote:
Hmmm...I guess I am confused. I thought transitional links *were* adaptation components of the topology (and vice versa). A selected path that transited/transitioned an adaptation componet had to configure that adaptation at provisioning time;
As far as I understand it Transitional Links were introduced to create an abstraction of the adaptation and links underneath it.
I think though, whatever you call it or where ever it is in the topology, transitional links / adaptation components function differently in two different situations: a) Encapsulation, and b) stitching. The former, is a "vertical" transition where the upper layer protocol is tunneled in its entirety through the lower layer protocol (ala IP/Ethernet, or Ethernet/sonet (via GFP adaptation) ) and must have a matching decapsulation function at the egress, and the latter is more "horizontal" transition where the current transport protocol is stripped in its entirety leaving only the user data payload which is then placed in the next transport protocol for forwarding (the stitching adaptation does not require a matching function at its egress point - only whatever it needs for the next stage). Does this jive with the discussion and other papers on these concepts?
If I understand correctly the distinction you make has already been proposed by Guy earlier: forwarding (your "vertical") and switching ("horizontal"). Jeroen.