Channel over a link -  A channel seems like a NSI segment.  It could be described as a link over a link at a different layer.


What seems missing --

1) The description of adapatation in general:  for example in a concatenated series of links, each concatenated link may be carried on a different sort of higer layer link.  A VLAN might be carried on an Ethernet link (as a VLAN), on a SONET link as GFP encoded VLAN.   In this case the underlying link with its coding is carried over different higher layer links with their coding.

2) The concept of connection oriented network:  A NSI network is something that can create segments (aka links a lower layer) between edge points (aka ports). A network participates with other networks in a topology where the elements are networks that connected with links.  In graph theory network would be node, and link an edge.

3) Names for the elements within a layer that are concatenated.  NSI calls these segments for now.  The NSI topology elements are links and networks.  Each of these elements can provide segments and the segments can be concatenated to create a ete segment.  I believe that segments and links at a level are identical concepts, so  perhaps we can come up with an alias for how to describe NSI segments and ete concatenated segments.

Are there questions or corrections?  Comments on how to come to understanding and consensus for this?

I suggest that we might want to have a call to start discussions on this before OGF and to try to resolve issues at OGF.   There is a NSI call every Wed at 9ET - we could have a joint call on Wed May 20 if that seems reasonable.

John

On May 7, 2009, at 10:21 AM, Freek Dijkstra wrote:

John Vollbrecht wrote:

Attached is a try at defining needs of NSI from NML.  Some if it uses NMwg terminology as I understand it.

I am thinking it would be good to sort this out and get a good definition by the end of OGF.

Hi John,

Thanks for writing this down -- a few comments.

You mix the NMwg with the NML terminology -- the NML terminology has improved much since the NMwg documents, and will deprecate the NMwg schema.

Here is a comparison table between NML and NSI, as far as we see.

NSI                NML

End Device    ---  Node

Edgepoint     ---  Port

Network       ---  Topology  (*1)

Link          ---  Link

Segment       ---  (under discussion)

Service Group ---  n/a

Level         ---  Layer

(*1) If I understand your "network" correctly; the term network has different meanings.

Segment is still under discussion. We've used the term "Channel" a few times, but there is no group consensus. Segment refers to a multi layer concept, which will be defines in a separate schema.

NML hasn't defined Service Group. It seems an important concept, so perhaps we should.

Have you seen the terminology comparison table at

http://forge.gridforum.org/sf/go/doc15512

Regards,

Freek Dijkstra

Jeroen van der Ham