Re: [mpls] MPLS label and LSE data models

["Acee Lindem (acee)" <[e-mail]>]

Hi Greg,


From: Greg Mirsky <[e-mail]<mailto:[e-mail]>>
Date: Monday, June 5, 2017 at 8:43 PM
To: Acee Lindem <[e-mail]<mailto:[e-mail]>>
Cc: "[e-mail]<mailto:[e-mail]>" <[e-mail]<mailto:[e-mail]>>, "[e-mail]<mailto:[e-mail]>" <[e-mail]<mailto:[e-mail]>>, Routing WG <[e-mail]<mailto:[e-mail]>>, "[e-mail]<mailto:[e-mail]>" <[e-mail]<mailto:[e-mail]>>
Subject: Re: MPLS label and LSE data models

Hi Acee,
I think rather of the contrary, Static MPLS LSP must include TC and TTL. And Bottom-of-the-stack flag as well (I don't see it in grouping mpls-label-stack of the ietf-routing-types).

I just looked at a couple implementations and they do not include per-label provisioning of the traffic class and TTL. One would certainly NOT want to provision bottom of stack. Even if you put it in the rightmost label, other routes which are already labeled could resolve over the static LSP.

As far as adding a separate leaf list for the mpls-label type, I don’t think this is necessary as adding a type just to abstract a YANG list just adds complexity.

Anyway, I’m deferring to the authors of the MPLS static model if they desire any additional types in ietf-routing-types.

Thanks,
Acee


Regards,
Greg

On Mon, Jun 5, 2017 at 4:55 PM, Acee Lindem (acee) <[e-mail]<mailto:[e-mail]>> wrote:
Greg, et al,

From: Greg Mirsky <[e-mail]<mailto:[e-mail]>>
Date: Monday, June 5, 2017 at 6:28 PM
To: "[e-mail]<mailto:[e-mail]>" <[e-mail]<mailto:[e-mail]>>, "[e-mail]<mailto:[e-mail]>" <[e-mail]<mailto:[e-mail]>>
Cc: Routing WG <[e-mail]<mailto:[e-mail]>>, "[e-mail]<mailto:[e-mail]>" <[e-mail]<mailto:[e-mail]>>
Subject: MPLS label and LSE data models
Resent-From: <[e-mail]<mailto:[e-mail]>>
Resent-To: Yingzhen Qu <[e-mail]<mailto:[e-mail]>>, <[e-mail]<mailto:[e-mail]>>, Acee Lindem <[e-mail]<mailto:[e-mail]>>, Christian Hopps <[e-mail]<mailto:[e-mail]>>, <[e-mail]<mailto:[e-mail]>>
Resent-Date: Monday, June 5, 2017 at 6:28 PM

Dear Authors, et.al<http://et.al>,
I've got a question, or several of them, about data models of MPLS label and MPLS label stack element (LSE). I ahve not followed the discussions and apologize if these already were considered, discussed.
In the Routing Types document I've found that only MPLS label being modeled but not the MPLS LSE. As result, models that use rt-types:mpls-label, e.g. YANG DAta Model for MPLS Static LSPs, defines outgoing labels not as array of LSEs but as array (leaf-list) of MPLS labels. In the latter document I don't see how TTL and Traffic Class (TC) are presented for each of labels in the array. Hence my questions:

  *   should there be data model of MPLS LSE in rt-types (it does have TTL and TC but separately);

  *   should data model of Static MPLS LSP use MPLS LSE model rather than model of only 20 bit-long label.

Where else so you see  a requirement for a label stack with entries that don’t contain TC and TTL? This seems specific to static provisioning of static LSPs rather than a general requirement for ietf-routing-types.

Thanks,
Acee


Appreciate you comments.

Regards,
Greg