Re: [Teas] Transport slice negotiation

[Eric Gray <[e-mail]>]

Hey, Igor.

First, a little context.  We are not just starting this work; we started this work last year.  And the intent in this work is to define relevant components, including an abstract northbound interface (NBI) - which is the way that a transport slice client requests a specific transport slice service over a minimally specified underlay network - and a framework for subsequent development (of models, for instance).

Our intent is not to redo (or replace) any specific work that has been completed, or is already in progress in the IETF, generally, and certainly not redo/replace work done in the TEAS WG specifically.

If you could be precise as to what work on "YANG TE Topology model" it is that you refer to, perhaps it would be possible to give an answer to the question as to why we did not (if indeed, we did not) start with that work.

If, for instance, you are referring to the L3SM - or L2SM - models, look at the text in the definitions draft (section 5.2 - "Transport Slice Controller Interfaces"), specifically where we talk about the transport slice controller (TSC) southbound interface (SBI) and list examples including these two cases.

We also have included ACTN and VPN+ in the framework draft.

If you feel we should add more examples from other TEAS work, to either or both drafts, please feel free to propose text - or at least work with members of the design team to construct text we can include.

Thanks, in advance,
--
Eric


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Igor Bryskin <[e-mail]> Fri, 15 May 2020 13:58 UTC wrote: 
 
Hi Joel,

 

Per your suggestion I am putting this discussion on the list. Thank you for your response.

Please, see a comment/suggestion in-line.

 

Regards,

Igor

 

On Thursday, May 14,2020, 9:50:19 AM EDT, Joel M. Halpern mailto:&lt;[e-mail]&gt; wrote: 

 

 

Thank you for the summary of the agreements below.  That helps 
significantly.  I am happy to provide my personal perspective on the 
questions you ask.  There is plenty of room for compromise.

On homogeneity, I tend to expect that things are non-uniform, and 
therefore the SLO specification needs to be able to be endpoint pair 
specific some of the time.  (I tend to like something along the lines of 
PNNI where on provides the base uniform value and then exceptions for 
specific better or worse cases.)

 

IB>> As you know, in TEAS WG we have developed YANG TE Topology model that allows to do exactly this. Specifically, it allows for a client for a give abstract TE node (and entire network or slice could be described as a single abstract TE node) to specify  a Connectivity Matrix (CM) of required Access Point to Access Point (AP-AP) connections/paths along with TE bounds on said paths, such as minimal available bandwidth, maximal permissible delay, required protection capabilities, etc. Additionally, the CM includes a container - Default Connectivity Matrix Entry - which is supposed to simplify a homogeneous connectivity configuration. Specifically, a TE bound configured within Default Connectivity Matrix Entry should apply to any valid AP-AP path,  as long as the path specific entry bound does not explicitly overwrites it.

 

Why don't we start with this? If we decide along the road that some AP-AP path specific parameters are missing (e.g. path availability metric), a simple augmentation would fill the gaps. What do you think?

 

Igor  

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