Re: [Idr] draft-xie-idr-bgpls-sr-vtn-mt-03.txt - Call for WG adoption: 12/18/2021 to 1/7/2022

Hi Luis,

Thanks for your support and comment. Please see some replies inline:

From: Idr [mailto:idr-bounces@ietf.org] On Behalf Of Luis M. Contreras
Sent: Saturday, January 8, 2022 12:13 AM
To: Susan Hares <shares@ndzh.com>
Cc: idr@ietf.org
Subject: Re: [Idr] draft-xie-idr-bgpls-sr-vtn-mt-03.txt - Call for WG adoption: 12/18/2021 to 1/7/2022

Hi All,

I think the draft is valuable, so I support the adoption of this draft. Regarding Sue's questions:

1) I see it applicable to general situations as well, not only for 5G scenarios (in fact talking of 5G scenarios where in some specific cases there could be very stringent requirements - e.g., latency or jitter - is something that could require further assessment).

[Jie] Agree this mechanism can be used for both 5G and the general cases.

2) The draft mentions that " (Abstract) The association between the network topology, the network resource attributes and the SR SIDs may need to be distributed to a centralized network controller." and then "(Section 2.2) In network scenarios where consistent usage of MT-ID among multiple domains can not be expected, a global-significant VTN-ID needs to be introduced to define the inter-domain topologies." So it is not clear to me if some additional signaling between controllers in different domains could map the MT-IDs in each particular domain instead of going for a global VTN-ID (which anyway should require some agreement between controllers as well). I think this part requires more elaboration (could it even deserve a separate document for that?).

[Jie] This document mainly targets on the scenarios where consistent usage of MT-ID among multiple domains can be achieved. For scenarios where consistent MT-ID is not possible, your point about providing mapping between the MT-IDs in different domains is something could be considered further, and it may be an alternative to the global VTN-ID approach.

Best regards,
Jie

Best regards

Luis

El sáb, 18 dic 2021 a las 17:33, Susan Hares (<shares@ndzh.com<mailto:shares@ndzh.com>>) escribió:
This begins a WG Adoption call for draft-xie-idr-bgpls-sr-vtn-mt-03.txt from 12/18 2021 to 1/7/2022.  The longer period is due to the Holiday/New Year time period.

The draft can be found at:
https://datatracker.ietf.org/doc/draft-xie-idr-bgpls-sr-vtn-mt/

While reviewing the document consider the following questions:

1)  Does this informational draft aid operation of 5G networks for new applications?

New 5G services require stringent  performance requirements for applications.  This information draft describes how to use existing segment routing (SR)
mechanisms to allow a centralized control to allocate a set of  virtual transport networks (VTNs) which are resource aware.  Isolation between resources for multi-AS transport may be necessary to protect the application.

Intra-domain:
a) Uses MT-ID which identifies 1 or more ISIS/OSPF topologies.
[drafts referenced:  draft-ietf-idr-rfc7752bis, draft-ietf-idr-bgp-ls-segment-routing-ext,  draft-ietf-idr-bgpls-srv6-ext]
b) New VTN-ID which specifies resources associated with each VTN
[draft referenced: draft-ietf-lsr-isis-sr-vtn-mt]

Inter-Domain mechanisms used include:
a) Isolation of certain VTNs to specific inter-domain links or BGP peers,
b) consistent use of MT-ID across multiple domains or use of VTN-ID TLV

VTN-ID TLV is a bgp-ls TLV that specifies unique set of resources per VTN.

[existing WG drafts referenced: draft-ietf-idr-bgpls-segment-routing-epe, draft-ietf-idr-bgpls-srv6-ext, draft-ietf-idr-rfc7752bis]
New drafts referenced: draft-dong-idr-bgpls-sr-enhanced-vpn-03.txt]

2) Should IDR recommend the global VTN-ID?

The MT-ID is not an IANA registered named space.  VTN-ID is proposed as a global name space, but does not have any proposed IANA registry text.  Should VTN-ID become a register global name space that identifies a set of MT-IDs and other resources?

Cheers, Sue

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___________________________________________
Luis M. Contreras
contreras.ietf@gmail.com<mailto:contreras.ietf@gmail.com>
luismiguel.contrerasmurillo@telefonica.com<mailto:luismiguel.contrerasmurillo@telefonica.com>
Global CTIO unit / Telefonica