Network-Assigned Upstream Label
draft-ietf-teas-network-assigned-upstream-label-12

[Ballot comment]
Per email exchange:


I wrote:
Can an upstream node have multiple labels that it is receiving
traffic on?  I assume that the answer is "yes". If so, what happens if
the downstream node picks a label that collides with another label?

Response is:
[VPB] Yes, it is possible for the downstream node to pick a symmetric label that is not acceptable to the upstream node. The upstream node responds with a ResvErr in such cases (this is usual Generalized Label Object processing — See Section 2.3 in RFC3473) and the downstream node would end up picking something else. In order to avoid this unnecessary exchange, the upstream node would include a LABEL_SET object in the PATH message. The LABEL_SET object will carry a list of valid labels that are acceptable on the Upstream node.


The text isn't entirely clear on this point. The most on-point thing seems to be:
  In response, the downstream node picks an appropriate symmetric label
  and sends it via the LABEL object in the Resv message.  The upstream
  node would then start using this symmetric label for both directions
  of the LSP.  If the downstream node cannot pick the symmetric label,
  it MUST issue a PathErr message with a "Routing Problem/Unacceptable
  Label Value" indication.  If the upstream node that signals an
  Unassigned Upstream Label receives a label with the "all-ones"
  pattern in the LABEL object of the Resv message, it MUST issue a
  ResvErr message with a "Routing Problem/Unacceptable Label"
  indication.

  The upstream node will continue to signal the Unassigned Upstream
  Label in the Path message even after it receives an appropriate
  symmetric label in the Resv message.  This is done to make sure that
  the downstream node would pick a different symmetric label if and
  when it needs to change the label at a later time.  If the upstream
  node receives an unacceptable changed label, then it MUST issue a
  ResvErr message with a "Routing Problem/Unacceptable Label"
  indication.

But the first graf talks about all ones and the second talks about subsequent changes. Neither addresses the initial label

[Ballot comment]
I believe you when you say this

  As per the existing
  setup procedure outlined for a bidirectional LSP, each upstream node
  must allocate a valid upstream label on the outgoing interface before
  sending the initial Path message downstream.  However, there are
  certain scenarios where it is not desirable or possible for a given
  node to pick the upstream label on its own.  This document defines
  the protocol mechanism to be used in such scenarios.

but I wonder if you could give an example or two of those "certain scenarios", so that readers would know whether they need to keep reading.

After reading all of Section 3, I found myself wondering whether that use case was one of the "certain scenarios", but I couldn't tell for certain. If it is, even a forward reference to Section 3 in the Introduction would have helped me.

(Via drafts-lastcall@iana.org): IESG/Authors/WG Chairs:

The IANA Services Operator has completed its review of draft-ietf-teas-network-assigned-upstream-label-09. If any part of this review is inaccurate, please let us know.

The IANA Services Operator has a question about the action requested in the IANA Considerations section of this document.

The IANA Services Operator understands that, upon approval of this document, there is a single action which we must complete.

A new registry is to be created called the Special Purpose Generalized Label Values registry. The new registry is to be created on the Generalized Multi-Protocol Label Switching (GMPLS) Signaling Parameters registry page located at:

https://www.iana.org/assignments/gmpls-sig-parameters/

The new registry will be managed via Standards Action as defined in RFC 8126. There is a single, initial registration in the new registry as follows:

Pattern/ Label Name Applicable Reference
Value Objects
-----------+---------------------+-----------------+-------------
all-ones Unassigned UPSTREAM_LABEL [ RFC-to-be ]
Upstream Label

IANA Question --> We understand that a downstream node may send a label with the "all ones" pattern in the LABEL object of the Resv message. Should the registry entry be a set of (32) literal digits "1" - rather than the text "all-ones? How will future values be represented? We understand that the Label is 32-bits.

The IANA Services Operator understands that this is the only action required to be completed upon approval of this document.

Note:  The actions requested in this document will not be completed until the document has been approved for publication as an RFC. This message is only to confirm the list of actions that will be performed.


Thank you,

Sabrina Tanamal
Senior IANA Services Specialist

The following Last Call announcement was sent out (ends 2017-12-29):

From: The IESG
To: IETF-Announce
CC: draft-ietf-teas-network-assigned-upstream-label@ietf.org, db3546@att.com, teas-chairs@ietf.org, teas@ietf.org, Lou Berger , lberger@labn.net
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (Network Assigned Upstream-Label) to Proposed Standard


The IESG has received a request from the Traffic Engineering Architecture and
Signaling WG (teas) to consider the following document: - 'Network Assigned
Upstream-Label'
  as Proposed
  Standard

The IESG plans to make a decision in the next few weeks, and solicits final
comments on this action. Please send substantive comments to the
ietf@ietf.org mailing lists by 2017-12-29. Exceptionally, comments may be
sent to iesg@ietf.org instead. In either case, please retain the beginning of
the Subject line to allow automated sorting.

Abstract


  This document discusses a Generalized Multi-Protocol Label Switching
  (GMPLS) Resource reSerVation Protocol with Traffic Engineering (RSVP-
  TE) mechanism that enables the network to assign an upstream label
  for a bidirectional Label Switched Path (LSP).  This is useful in
  scenarios where a given node does not have sufficient information to
  assign the correct upstream label on its own and needs to rely on the
  downstream node to pick an appropriate label.  This document updates
  RFCs 3471, 3473 and 6205 as it defines processing for a special label
  value in the UPSTREAM_LABEL object.





The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-teas-network-assigned-upstream-label/

IESG discussion can be tracked via
https://datatracker.ietf.org/doc/draft-ietf-teas-network-assigned-upstream-label/ballot/


No IPR declarations have been submitted directly on this I-D.

> As required by RFC 4858, this is the current template for the Document
> Shepherd Write-Up.
>
> Changes are expected over time. This version is dated 24 February 2012.
>
> (1) What type of RFC is being requested (BCP, Proposed Standard,
> Internet Standard, Informational, Experimental, or Historic)?

Standards Track

> Why is this the proper type of RFC?

It defines protocol processing rules that must be followed by multiple
nodes/independent implementations.

> Is this type of RFC indicated in the
> title page header?

Yes

> (2) The IESG approval announcement includes a Document Announcement
> Write-Up. Please provide such a Document Announcement Write-Up. Recent
> examples can be found in the "Action" announcements for approved
> documents. The approval announcement contains the following sections:
>
> Technical Summary
>
>  Relevant content can frequently be found in the abstract
>  and/or introduction of the document. If not, this may be
>  an indication that there are deficiencies in the abstract
>  or introduction.

  This document discusses a Generalized Multi-Protocol Label Switching
  (GMPLS) Resource reSerVation Protocol with Traffic Engineering (RSVP-
  TE) mechanism that enables the network to assign an upstream label
  for a bidirectional LSP.  This is useful in scenarios where a given
  node does not have sufficient information to assign the correct
  upstream label on its own and needs to rely on the downstream node to
  pick an appropriate label.
 
> Working Group Summary
>
>  Was there anything in WG process that is worth noting? For
>  example, was there controversy about particular points or
>  were there decisions where the consensus was particularly
>  rough?

This document moved from to the TEAS WGs as part of the routing WG
changes.  This document has been fairly noncontroversial.

>
> Document Quality
>
>  Are there existing implementations of the protocol? Have a
>  significant number of vendors indicated their plan to
>  implement the specification? Are there any reviewers that
>  merit special mention as having done a thorough review,
>  e.g., one that resulted in important changes or a
>  conclusion that the document had no substantive issues? If
>  there was a MIB Doctor, Media Type or other expert review,
>  what was its course (briefly)? In the case of a Media Type
>  review, on what date was the request posted?


The extensions defined in this document are compatible with known
implementations.  While there have been no public statements on
implementation, the authors are from multiple vendors, and
implementation is expected - or may even already exist.

> Personnel
>
>  Who is the Document Shepherd?

Lou Berger

> Who is the Responsible Area Director?

Deborah Brungard

> (3) Briefly describe the review of this document that was performed by
> the Document Shepherd.  If this version of the document is not ready
> for publication, please explain why the document is being forwarded to
> the IESG.


The Document Shepherd has reviewed the document as part of normal WG
progress and WG last call.  The Shepherd believes this document is ready
for publication.


> (4) Does the document Shepherd have any concerns about the depth or
> breadth of the reviews that have been performed?

no

> (5) Do portions of the document need review from a particular or from
> broader perspective, e.g., security, operational complexity, AAA, DNS,
> DHCP, XML, or internationalization?

No.

> If so, describe the review that took place.

N/A.

>
> (6) Describe any specific concerns or issues that the Document Shepherd
> has with this document that the Responsible Area Director and/or the
> IESG should be aware of? For example, perhaps he or she is uncomfortable
> with certain parts of the document, or has concerns whether there really
> is a need for it. In any event, if the WG has discussed those issues and
> has indicated that it still wishes to advance the document, detail those
> concerns here.

No blocking concerns.  There is a simplification taken in the
compatibility approach that justifies this document being an update to
3473. 

> (7) Has each author confirmed that any and all appropriate IPR
> disclosures required for full conformance with the provisions of BCP 78
> and BCP 79 have already been filed. If not, explain why.
>
Yes, see thread at
https://www.ietf.org/mail-archive/web/teas/current/msg02323.html

> (8) Has an IPR disclosure been filed that references this document?
> If so, summarize any WG discussion and conclusion regarding the IPR
> disclosures.

No IPR disclosed.

> (9) How solid is the WG consensus behind this document? Does it
> represent the strong concurrence of a few individuals, with others
> being silent, or does the WG as a whole understand and agree with it? 

Solid among those who are interested. "strong concurrence of a few
individuals, with others being silent" is a reasonable
characterization.

> (10) Has anyone threatened an appeal or otherwise indicated extreme
> discontent? If so, please summarise the areas of conflict in separate
> email messages to the Responsible Area Director. (It should be in a
> separate email because this questionnaire is publicly available.)

No discontent seen.

>
> (11) Identify any ID nits the Document Shepherd has found in this
> document. (See http://www.ietf.org/tools/idnits/ and the Internet-Drafts
> Checklist). Boilerplate checks are not enough; this check needs to be
> thorough.

The document passes ID nits.

>
> (12) Describe how the document meets any required formal review
> criteria, such as the MIB Doctor, media type, and URI type reviews.

N/A.

> (13) Have all references within this document been identified as
> either normative or informative?

Yes.

> (14) Are there normative references to documents that are not ready for
> advancement or are otherwise in an unclear state? If such normative
> references exist, what is the plan for their completion?

No.

> (15) Are there downward normative references references (see RFC 3967)?
> If so, list these downward references to support the Area Director in
> the Last Call procedure.

No.

> (16) Will publication of this document change the status of any
> existing RFCs? Are those RFCs listed on the title page header, listed
> in the abstract, and discussed in the introduction? If the RFCs are not
> listed in the Abstract and Introduction, explain why, and point to the
> part of the document where the relationship of this document to the
> other RFCs is discussed. If this information is not in the document,
> explain why the WG considers it unnecessary.

No.

> (17) Describe the Document Shepherd's review of the IANA considerations
> section, especially with regard to its consistency with the body of the
> document. Confirm that all protocol extensions that the document makes
> are associated with the appropriate reservations in IANA registries.
> Confirm that any referenced IANA registries have been clearly
> identified. Confirm that newly created IANA registries include a
> detailed specification of the initial contents for the registry, that
> allocations procedures for future registrations are defined, and a
> reasonable name for the new registry has been suggested (see RFC 5226).

The IANA section was fully reviewed by the document shepherd and is
appropriate for an this draft.


> (18) List any new IANA registries that require Expert Review for future
> allocations. Provide any public guidance that the IESG would find
> useful in selecting the IANA Experts for these new registries.

None.

> (19) Describe reviews and automated checks performed by the Document
> Shepherd to validate sections of the document written in a formal
> language, such as XML code, BNF rules, MIB definitions, etc.

N/A

Pre LC IPR Poll responses:
Xian Zhang : https://www.ietf.org/mail-archive/web/teas/current/msg02336.html

STILL Waiting on:
Oscar de Dios ,
Igor Bryskin ,
jdrake@juniper.net,
ggrammel@juniper.net,
pbrzozowski@advaoptical.com,
  zali@cisco.com

Pre LC IPR Poll responses:
Daniele Ceccarelli : https://www.ietf.org/mail-archive/web/teas/current/msg02331.html
Vishnu Beeram :  https://www.ietf.org/mail-archive/web/teas/current/msg02329.html

Waiting on:
Oscar de Dios ,
Xian Zhang ,
Igor Bryskin ,
jdrake@juniper.net,
ggrammel@juniper.net,
pbrzozowski@advaoptical.com,
  zali@cisco.com

Pre LC IPR Poll: Waiting on 
Oscar de Dios ,
Daniele Ceccarelli ,
Vishnu Beeram ,
Xian Zhang ,
Igor Bryskin ,
jdrake@juniper.net,
ggrammel@juniper.net,
pbrzozowski@advaoptical.com,
  zali@cisco.com
See https://www.ietf.org/mail-archive/web/teas/current/msg02322.html