Re: [mpls] discussion on a common top for yang models related to MPLS

Phil Bedard <> Wed, 10 February 2016 00:23 UTC

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Date: Tue, 09 Feb 2016 19:23:46 -0500
From: Phil Bedard <>
To: "Rajiv Asati (rajiva)" <>, Loa Andersson <>, "" <>
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Thread-Topic: [mpls] discussion on a common top for yang models related to MPLS
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Subject: Re: [mpls] discussion on a common top for yang models related to MPLS
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There is a consolidated MPLS model introduced by OpenConfig, the 02 version publisehd in October of last year.

It has a base model which then has three different sub-models defined in the hierarchy covering types of LSPs: static, IGP-congruent/unconstrained (routing-dependent), and TE/constrained.  



-----Original Message-----
From: mpls <> on behalf of "Rajiv Asati (rajiva)" <>
Date: Tuesday, February 9, 2016 at 10:43
To: Loa Andersson <>, "" <>
Subject: Re: [mpls] discussion on a common top for yang models related to MPLS

>My preference wasn’t quite clear in the previous email, so let me state it explicitly - (1), IMO, MPLS base should reside off the root, and for (2) it might be worth dividing the subsequent models as either non-routing or routing, given that MPLS control plane e.g. LDP would be routing dependent, whereas static LSP _could_ not be. 
>For (2), a hierarchy something like his works out (where non-routing is nothing but MPLS base)
>	MPLS Base
>		<non-routing>
>			Static LSP
>		<routing>
>			Static LSP
>			Dynamic LSP - LDP, mLDP, RSVP-TE, 
>However, it creates an interesting challenge for aligning the yang models and while keeping the hierarchy simple.
>Is it worth having a focused team figuring out MPLS base staying off the root, whereas routing-dependent MPLS control plane protocols e.g. LDP staying off routing?
>Rajiv Asati
>Distinguished Engineer, Cisco
>-----Original Message-----
>From: Rajiv Asati <>
>Date: Friday, February 5, 2016 at 8:58 AM
>To: Loa Andersson <>, "" <>
>Subject: Re: [mpls] discussion on a common top for yang models related to MPLS
>>I definitely agree (co-author hat off, and user hat on). Avoiding duplication and doing better organization would indeed be a good thing to do.   
>>1) If MPLS base model (and subsequent models - LDP, TE etc.) augments the (IP) routing/routing-protocol, then it might not well apply to GMPLS. Is there an existing thought-process on this topic? 
>>Either ignore the above and have GMPLS argument mpls base model as is, or get MPLS base on an independent path (off of (IP) routing/routing-protocol) and work out the subsequent models.
>>2) In terms of hierarchy, is the below envisioned?
>>	MPLS base => Static LSP and dynamic LSP
>>		MPLS static LSP => 
>>		MPLS dynamic LSP => 	
>>			LDP
>>			mLDP (MP)
>>			TE (RSVP-TE P2P)
>>			TE (RSVP-TE P2MP)			    
>>-----Original Message-----
>>From: mpls <> on behalf of Loa Andersson <>
>>Date: Friday, February 5, 2016 at 7:34 AM
>>To: "" <>
>>Subject: [mpls] discussion on a common top for yang models related to MPLS
>>>We have had discussion among the MPLS, TEAS and CCAMP working group
>>>chairs - but as individual contributors, with chair half off. We agree
>>>that this discussion should be taken to the working group(s).
>>>The YANG models for MPLS and GMPLS are quite rapidly taking shape. MPLS
>>>and GMPLS technologies have traditionally been very close, but their
>>>development has been a bit disjoint. For the YANG models we would like
>>>to minimize duplication of models/work and think the structure should
>>>have a common the top,  with specific technologies augmented below.
>>>The structure in general as well as the YANG model at the common top
>>>needs to be the generic and aligned across the output of at least
>>>CCAMP, MPLS and TEAS working groups. There has been good work 
>>>progressing on TE specifics, e.g., see draft-ietf-teas-yang-te, but
>>>other areas remain. On the LDP side of the house draft-raza-mpls-
>>>ldp-mldp-yang is rapidly progressing towards working group adoption.
>>>The models defined in draft-saad-mpls-static-yang could serve as the
>>>start on filling some of the remaining gaps; covering core xMPLS
>>>definitions and static LSPs.  There are a number of ways to make the
>>>structure intuitive and generic, and serve as a foundation for
>>>technology specific models.  -- This effort can be viewed as the same
>>>type of work that was done for TE, see draft-ietf-teas-yang-te.
>>>We think it would be a good idea  if the authors and the  WG considers
>>>how to structure xMPLS definitions and static LSPs models to best
>>>foster common use across the different related models being worked on 
>>>across  different WGs.
>>>We are sending this mail in hopes of getting this discussion started.
>>>Thank you,
>>>Lou and Loa
>>>Loa Andersson                        email:
>>>Senior MPLS Expert                
>>>Huawei Technologies (consultant)     phone: +46 739 81 21 64
>>>mpls mailing list
>mpls mailing list