RSVP ASSOCIATION Object Extensions
draft-ietf-ccamp-assoc-ext-06

[Ballot discuss]
My Discuss issues should be easy to resolve.

In my opinion, a little more detail could be provided in section 5 to
give guidance about backward compatibility when deploying the extended
ASSOCIATION objects described in this document.

First, an editorial nit: the third sentence is vague - what, exactly,
is "essentially also the action taken for unknown association types"
and where is that behavior specified?.

Second, I suggest it would be helpful to note that RFC 2209 requires
the generation of an error message for unknown C-types, so a
deployment of the extended ASSOCIATION across devices
that don't implement the new C-type will be indicated explicitly.

Finally, are there any compatibility issues with a node that
implements RFC 4872 ASSOCIATION objects and receives an ASSOCIATION
object generated according to the updated rules in this document?  In
that case, if I understand this document correctly, the ASSOCIATION
object will be compliant with RFC 4872; will the legacy implementation
correctly process the ASSOCIATION in that case?

[Ballot comment]


I wish I didn't get the feeling that someone is missing
something everytime I read the security considerations section
for MPLS documents. To be honest, it all just seems like too
good a deal, basically not having to worry about bad actors.
(Note: that's a general lament/whinge, not specific to this
document. Sorry about that;-)

IANA has reviewed Draft-ietf-ccamp-assoc-ext-04 and has the following comments:

IANA understands that, upon approval of this document, there are two
IANA Actions which must be completed.

First, in the "Class Types or C-Types ‒ 199 ASSOCIATION" subregistry of
the "Resource Reservation Protocol (RSVP) Parameters" registry located
at:

http://www.iana.org/assignments/rsvp-parameters

two new values need to be assigned:

Value: 3
Description: Type 3 IPv4 Extended Association
Reference: [ RFC-to-be ]

Value: 4
Description: Type 4 IPv6 Extended Association
Reference: [ RFC-to-be ]

Second, in the "Association Type" subregistry of the "Generalized Multi-Protocol
Label Switching (GMPLS) Signaling Parameters" registry located at:

http://www.iana.org/assignments/gmpls-sig-parameters/gmpls-sig-parameters.xml

the existing value for (2) Resource Sharing needs to be changed
as follows:

OLD:
2 Resource Sharing (R) [RFC4873]
NEW
2 Resource Sharing (S) [RFC4873][ RFC-to-be ]

IANA understands these to be the only actions 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.

The following Last Call announcement was sent out:

From: The IESG
To: IETF-Announce
CC:
Reply-To: ietf@ietf.org
Subject: Last Call:  (RSVP Association Object Extensions) to Proposed Standard


The IESG has received a request from the Common Control and Measurement
Plane WG (ccamp) to consider the following document:
- 'RSVP Association Object Extensions'
  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 2012-08-29. 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

  The RSVP ASSOCIATION object was defined in the context of GMPLS
  (Generalized Multi-Protocol Label Switching) controlled label
  switched paths (LSPs).  In this context, the object is used to
  associate recovery LSPs with the LSP they are protecting.  This
  object also has broader applicability as a mechanism to associate
  RSVP state, and this document defines how the ASSOCIATION object
  can be more generally applied.  This document also defines
  Extended ASSOCIATION objects which, in particular, can be used in
  the context of the Transport Profile of Multiprotocol Label
  Switching (MPLS-TP).  This document updates RFC 2205, RFC 3209,
  and RFC 3473. It also modifies the definition of the Association
  ID field defined in RFC 4872.


The file can be obtained via
http://datatracker.ietf.org/doc/draft-ietf-ccamp-assoc-ext/

IESG discussion can be tracked via
http://datatracker.ietf.org/doc/draft-ietf-ccamp-assoc-ext/ballot/


The following IPR Declarations may be related to this I-D:

  http://datatracker.ietf.org/ipr/1720/
  http://datatracker.ietf.org/ipr/1169/

AD review...

Hi,

I have done my usual AD review of this document prior to issuing IETF
last call. The purpose of my review is to catch any issues that might
come up in last call or IESG evaluation, and so smooth the path of the
document.

This seems to be a well-written I-D, thanks. I have just a few small
points that are mainly stylistic. A quick respin should address them.
I start with one fundamental question that I hope can be answered by
email.

Thanks,
Adrian

===

To start with, a key question:

Why does the working group want to publish this as an RFC when there
is no immediate intention to implement for any of the many scenarios
described in the document?

Will this become just another Standards Track RFC that gathers dust
and obfuscates the real protocol specs, or is there good reason to
publish it?

---

I can see how this updates 4872.

I am not convinced about this being an update to 2205, 3209 and 3473.

Let me ask the question as follows: Is this document needed in order to
produce a conformant implementation of RFC 2205 RSVP? In other words: is
it your intention that all new implementations of RSVP MUST include an
implementation of this document?

If the document does make the updates stated, it would be good if some
part of the document (maybe a new section, maybe just the Introduction)
contained text that described what has been updated.

Does Section 6.2 imply an update to RFC 4873?

---
                                       
Section 1

Some ambiguity, since it looks like the extension is to recovery
contexts other than GMPLS!

OLD
  This document expands the possible usage of the ASSOCIATION object to
  non-GMPLS recovery contexts. 
NEW
  This document expands the possible usage of the ASSOCIATION object to
  contexts other than GMPLS recovery. 
END

---

Section 1 Voice Call Waiting

      However,
      there is no way in RSVP today to share the resources between the
      A->B and A->C subflows of the call since by definition the RSVP
      reservations for these subflows must have different IP addresses
      in the SESSION objects.

Since you are defining such a mechanism, "there is no way today" is not
true. I suggest...

      Since, by definition, the RSVP reservations for the subflows A->B
      and A->C of the call must have different IP addresses in the
      SESSION objects, this document defines a new mechanism to
      associate the subflows and allow them to share resources.

Similarly...

OLD
    o Voice Shared Line:
      A single number that rings multiple endpoints (which may be
      geographically diverse), such as phone lines on a manager's desk
      and their assistant.  A VoIP system that models these calls as
      multiple P2P unicast pre-ring reservations would result in
      significantly over-counting bandwidth on shared links, since
      today unicast reservations to different endpoints cannot share
      bandwidth.
NEW
    o Voice Shared Line:
      A voice shared line is a single number that rings multiple
      endpoints (which may be geographically diverse), such as phone
      lines to a manager's desk and to their assistant.  A VoIP system
      that models these calls as multiple P2P unicast pre-ring
      reservations would result in significantly over-counting
      bandwidth on shared links, since RSVP unicast reservations to
      different endpoints cannot share bandwidth.  So a new mechanism
      is defined in this document allowing separate unicast
      reservations to be associated and share resources.
END

And...

OLD
    o Symmetric NAT:
      RSVP permits sharing of resources between multiple flows
      addressed to the same destination D, even from different senders
      S1 and S2.  However, if D is behind a NAT operating in symmetric
      mode [RFC5389], it is possible that the destination port of the
      flows S1->D and S2->D may be different outside the NAT.  In this
      case, these flows cannot share resources using RSVP today, since
      the SESSION objects for these two flows outside the NAT would
      have different ports.
NEW
    o Symmetric NAT:
      RSVP permits sharing of resources between multiple flows
      addressed to the same destination D, even from different senders
      S1 and S2.  However, if D is behind a NAT operating in symmetric
      mode [RFC5389], it is possible that the destination port of the
      flows S1->D and S2->D may be different outside the NAT.  In this
      case, these flows cannot share resources using RSVP, since the
      SESSION objects for these two flows outside the NAT have
      different ports.  This document defines a new mechanisms to
      associate these flows and allow them to share resources.
END

---

Globally...

s/extended ASSOCIATION/Extended ASSOCIATION/

---

Section 1

OLD
  This document also defines the extended ASSOCIATION objects which can
  be used in the context of Transport Profile of Multiprotocol Label
  Switching (MPLS-TP).  Although, the scope of the extended ASSOCIATION
  objects is not limited to MPLS-TP.
NEW
  This document also defines the Extended ASSOCIATION objects which can
  be used in the context of the Transport Profile of Multiprotocol
  Label Switching (MPLS-TP).  The scope of the Extended ASSOCIATION
  objects is not limited to MPLS-TP.
END

---

As with the previous ambiguity...

OLD
3. Non-GMPLS Recovery Usage
NEW
3. Uses other Than GMPLS Recovery
END

---

Section 3.1

s/defined generic/defines generic/

---

Section 3.1.2

  A node that wishes to
  allow downstream nodes to associate Path state across RSVP sessions
  MUST include an ASSOCIATION object in the outgoing Path messages
  corresponding to the RSVP sessions to be associated.

Yuck!

Are the sessions to be associated in the outgoing Path messages or the
Association object, or both. Actually, I don't think this needs a MUST,
but can be converted to descriptive text as follows.

  A node that wishes to allow downstream nodes to associate Path state
  across RSVP sessions sends a Path message corresponding to one RSVP
  session and includes in that message an ASSOCIATION object that
  indicates the associated RSVP sessions.

         
Then you have...

  In the absence
  of Association Type-specific rules for identifying association, the
  included ASSOCIATION objects MUST be identical across all associated
  sessions.

I know what you mean, but what you have said would require that a Path
message must contain an Association object that refers to itself. I
think what you need has to be more verbose to be accurate.

  In the absence
  of Association Type-specific rules for identifying association, each
  Path message for a session in a set of associated sessions MUST
  include an ASSOCIATION object that indicates all the other sessions
  in the set.

---

3.1.1 vs 3.2.1

In 3.1.1 you have...
  Relative ordering of ASSOCIATION objects of the same
  type SHOULD be preserved by transit nodes.

In 3.2.1 you have...
  Relative ordering of ASSOCIATION objects of the same
  type MUST be preserved by transit nodes.  Association type specific
  ordering requirements MAY be defined in the future.

1. Why is 3.1.1 SHOULD and 3.1.2 MUST?
2. Why does 3.2.1 consider association type-specific rules, but these
  are not in 3.1.1?
3. s/type specific/Type-specific/
4. Why "MAY" not "may"?

---

3.2.2

s/This section apply/This section applies/

---

3.3.1

  Once an association is identified, resources SHOULD be shared across
  the identified sessions.

This use of "SHOULD" begs the question: under what circumstances MAY
resource sharing not be applied?

---

Globally...

Please be consistent with:
- Association ID
- association-id

---

Section 4.1

Global Association Source: 4 bytes

      This field contains a value that is a unique global identifier.
      This field MAY contain the 2-octet or 4-octet value of the
      provider's Autonomous System Number (ASN).  It is expected that
      the global identifier will be derived from the globally unique ASN
      of the autonomous system hosting the Association Source.  The
      special value of zero (0) indicates that no global identifier is
      present. Note that a Global Association Source of zero SHOULD be
      limited to entities contained within a single operator.

Given the statement that the content is globally unique, I don't think
there is room for you to pontificate about how this field might be
filled. You need to make a definitive statement. Otherwise the content
cannot be guaranteed to be globally unique (unless you envisage a
central registration system!).

---                                                         

Section 4.1

  Extended Association ID: variable, 4-byte aligned

      This field contains data that is additional information to support
      unique identification.  The length and contents of this field is
      determined by the Association Source.  This field MAY be omitted,
      i.e., have a zero length.  This field MUST be padded with zeros
      (0s) to ensure 32-bit alignment.

This is confusing. I think that the length of the field is chosen by the
Association source and determined by the Length field of the Association
object.

But your text implies that the contents of the field may be different
from a four octet quantity. Since you have not included a separate
length indicator, this cannot be. The object length must always be a
multiple of 4 (says RFC 2205) and so there is no difference between a
zero padded field and a field where the zeros have meaning.

You *could* say that the length of this field is Association Type-
specific, but that would be ugly.

---

While you're at it, please note that draft-ietf-ccamp-assoc-info has
been published as RFC 6689

Proto-write-up for: draft-ietf-ccamp-assoc-ext-03.txt


(1) What type of RFC is being requested (BCP, Proposed Standard,
Internet Standard, Informational, Experimental, or Historic)? Why
is this the proper type of RFC? Is this type of RFC indicated in the
title page header?

Standards Track. Updates Standards Track RFCs. 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

The RSVP ASSOCIATION object was defined in the context of GMPLS
(Generalized Multi-Protocol Label Switching) controlled label
switched paths (LSPs). In this context, the object is used to
associate recovery LSPs with the LSP they are protecting. This
object also has broader applicability as a mechanism to associate
RSVP state, and this document defines how the ASSOCIATION object
can be more generally applied. This document also defines
extended ASSOCIATION objects which, in particular, can be used in
the context of Transport Profile of Multiprotocol Label Switching
(MPLS-TP). This document updates RFC 2205, RFC 3209, and RFC
3473. It also modifies the definition of the Association ID field
defined in RFC 4872.



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?

No. Good support by the WG.

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?

There have been no public statements related to implementations, though
significant interest was expressed by the working group.

Personnel

Who is the Document Shepherd? Who is the Responsible Area
Director?

Deborah Brungard is the Document Shepherd. Adrian Farrel is the
Area Director.

(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.

This document has been adequately reviewed.

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

No concerns.

(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? If so, describe the review that
took place.

No.

(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 concerns.

(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.

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

Yes, two related IPR disclosures. No concerns.

(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?

The WG supported this document.

(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.

(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.

No issues.

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

Not applicable.

(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.

Updates RFCs 2205, 3209, 3473, 4872 as listed.

(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).

IANA considerations section is clearly identified and appears appropriate.

(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.

Not applicable.

(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.

BNF rules are per RFC5511.