MPLS Transport Profile (MPLS-TP) Applicability: Use Cases and Design
draft-ietf-mpls-tp-use-cases-and-design-08

[Ballot comment]
This does sound like a lot of marketing fluff. *Why* did the WG think this was important to publish? Why was there "strong support in the WG"? Why is this "a reasonable contribution to the area of Internet engineering which it covers?"

[Ballot discuss]
Since I haven't seen any reply from the AD, authors, or shepherd to the comments from Stephen and the 3 B's (Barry, Benoit, and Brian), I'll DISCUSS for a moment just to get an answer; I intend to move immediately to NO OBJ or ABSTAIN:

This does sound like a lot of marketing fluff. *Why* did the WG think this was important to publish? Why was there "strong support in the WG"? Why is this "a reasonable contribution to the area of Internet engineering which it covers?"

[Ballot comment]

I did not think Section 1.2 was very informative. A rewrite in a different style would have made it better. These last call comments from Russ Housley were also on Section 1.2:

----

I wonder if the direction of Section 1.2 can be revised to make it more of an engineering document.

It currently says:

  In recent years, the urgency for moving from traditional transport
  technologies, such as SONET/SDH, TDM, and ATM, to new packet
  technologies has been rising. This is largely due to the fast growing
  demand for bandwidth, which has been fueled by the following factors:
  ...

Please consider an approach that describes the the reasons behind the transition from the network operator and network user perspectives:

  Traditional transport technologies include SONET/SDH, TDM, and ATM.
  There is a transition away from these transport technologies to new
  packet technologies. In addition to the ever increasing demand for
  bandwidth, the packet technologies offer these advantages:
  ...

The fact that IP networks are being used for new applications and that the legacy devices are getting old does not motivate the transition to packet technologies.  The advantages that packet technologies offer for these new applications is the thing that needs to be highlighted here, even if it is just a list of bullets.

It seems like the only sentence that addresses this point in Section 1.2 is: "It streamlines the operation, reduces the overall complexity, and improves end-to-end convergence."

[Ballot comment]
I tend to agree with Stephen's general sentiment regarding some marketing in the document.
However, as the write-up mentions "This document has a strong support in the working group and has been well reviewed.", I will record "no objection"

[Ballot comment]
I have to agree with Stephen that this really comes off more as a glossy brochure than as an IETF document.  But given the shepherd's contention that there's strong consensus in the working group to publish this, I'll say, "Mostly harmless."

[Ballot comment]
I'm fine with the current text wrt to "transport" (packet transport) vs. "transport" (TCP), as at least in my understanding the difference is clear in the text context of this particular draft.

[Ballot discuss]
The document says:

"Since IP/MPLS is largely deployed in most SPs' networks, MPLS-TP and
IP/MPLS Interworking is inevitable if not a reality. However,
Interworking discussion is out of the scope of this document; it is
for further study."

However not withstanding the text in 3.4 the issues of running MPLS-TP
OAM  over a non-MPLS-TP network fragment (in peer to peer, or
client-server mode) are quite severe since the non-MPLS-TP
network may break the network invariants that MPLS-TP OAM assumed,
and this needs to be called out in the text. This really needs to be
explained to the reader.

[Ballot comment]

- The "transport" (packet transport) vs. "transport"
(TCP) terminology divergence screams out here, even from
the moment one starts reading the ballot writeup.  The
routing and transport ADs might want to do something about
that sometime. (The transport ADs get 2x votes as to what to
do of course:-)

- Once I did start reading, my marketing-BS detectors
started firing big time. (See the specific comments
below.) To be honest, I think this kind of post-facto
justification marketing-spiel is mildly damaging to the
RFC series. Not enough to object, but enough to be
objectionable.

- 1.1, I dare you to invent expansions of 5G, 6G, 7G
etc.:-) And looking at this section, I don't believe all
the acronyms expanded are actually used, e.g. "AIS" seems
to occur exactly once in the document. There are also
seem to be acronyms that are expanded here that are used
exactly once which seems like a waste of space. And
lastly, expanding an acronym is not really the same as
defining a term, and this section does the former and not
the latter mostly.  So overall, this section seems not so
useful and more for forms sake or to make the document
look "more serious" both of which seem undesirable to
this reader.

- 1.2, "many legacy transport devices are approaching end
of life" - I'd love to see some references there, (since
I think that's an interesting fact, if its a fact) but
the phrase is also vague - do you mean the devices are
reaching end of life or the product lines are?

- 1.2, "MPLS family," "complements existing," "closes the
gap," "efficient, reliable" and "emerged as the next
generation transport technology of choice" all seem to me
to be purely marketing terms and are all are used within
one paragraph here. Phrases in subsequent paragraphs
outdo this one. IMO the best IETF marketing materials
involve code and/or technical detail of existing
deployment details and we're really not the best place
from which to launch this kind of text. (It turned me off
the rest of the document anyway fwiw, I'd never have read
the whole thing if I didn't have to ballot on it.)

- 2.1, "becoming inadequate," "too expensive to
maintain," without references those are merely truth by
blatent assertion. "a natural choice" also grates.

- 2.1, "most Service Provider's core networks are MPLS
enabled" seems to scream for a reference

- 2.1, "it reduces OPEX" seems similarly without factual
backing, "improves network efficiency" begs for a metric
and "reduces end-to-end convergence time" is talking
about something I'm sure, but its not clear what.

(At this point, I'm gonna stop calling out marketing
text. There's too much and it'd take too long. And it
turns out the only comments I would have had were
negative "we don't do marketing" things anyway;-)

IANA has reviewed draft-ietf-mpls-tp-use-cases-and-design-06, which is
currently in Last Call, and has the following comments:

We understand that, upon approval of this document, there are no
IANA Actions that need completion.

The following Last Call announcement was sent out:

From: The IESG
To: IETF-Announce
CC:
Reply-To: ietf@ietf.org
Subject: Last Call:  (MPLS-TP Applicability; Use Cases and Design) to Informational RFC

The IESG has received a request from the Multiprotocol Label Switching WG
(mpls) to consider the following document:
- 'MPLS-TP Applicability; Use Cases and Design'
  as Informational RFC

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 2013-02-11. 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 provides applicability, use case studies and network
  design considerations for the Multiprotocol Label Switching Transport
  Profile (MPLS-TP). The use cases include Metro Ethernet access and
  aggregation transport, Mobile backhaul, and packet optical transport.

The file can be obtained via
http://datatracker.ietf.org/doc/draft-ietf-mpls-tp-use-cases-and-design/

IESG discussion can be tracked via
http://datatracker.ietf.org/doc/draft-ietf-mpls-tp-use-cases-and-design/ballot/


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

It sounds like the revision to address the AD review will necessitate some major changes and the I-D will need to be run back through the Working Group.

AD Review

Hi,

I have done my AD review of this document as usual before pushing it
forward for IETF last call and IESG review. This has generated a long
list of comments. Many are formatting and style issues that really
should be fixed to make the document acceptable for publication. Others
are technical questions that need to be resolved either in discussion
or by updates to the document.

The volume of changes will make for quite a bit of extra work, I'm
afraid. But I think these changes are necessary before I can support
this document for publication as an RFC.

Please work with the chairs and the working group to resolve these
issues.

Thanks,
Adrian

===

In reading the document I find the authors are confused about what they
mean by MPLS-TP. Is MPLS-TP a profile of the MPLS toolset for use in
transport networks? Is it a profile of the MPLS functions that are used
in transport networks? Is it a delta to the base MPLS functions? Is it
a project to enhance the base MPLS to add features needed for transport
networks.

This question results in significant ambiguity in the text. For example,
you say "MPLS-TP disallowed ECMP", but I think you mean that "ECMP is
not appropriate in a transport network, so the MPLS transport profile
assumes that ECMP will not be present and the MPLS tools necessary for
handling ECMP will not be used."

---

Please fix the format nits shown by idnits (page and line lengths).

---

Per the exchanges on the MPLS mailing list, you need to replace "PHP as
optional" with "PHP must be disabled by default"

---

It would significantly help the reviewers if you could manage to
format the page headers and footers, align the section headings.

---

The Table of Contents is a bit messed up.

---

There are a number of random page throws that mess up the formatting.

---

This document desperately needs review by a native speaker to tidy the
English. While this might not seem critical, the large number of small
errors make reading and reviewing hard. They may also obscure some
technical issues.

I strongly suggest that the chairs solicit a review from an interested
working group member (in return for a mention in the Acknowledgements,
or in exchange for beer).

Here are a few examples from early in the document...

- - - -

Abstract

OLD
  for Multiprotocol Label Switching Transport
  profile (MPLS-TP).
NEW
  for the Multiprotocol Label Switching Transport
  Profile (MPLS-TP).

- - - -

Abstract

OLD
  The
  design considerations discussed in this documents ranging from
NEW
  The
  design considerations discussed in this document range from

- - - -

Section 1.1

OLD
The end of live for many
NEW
The end of life for many

- - - -

Section 1.1

OLD
  MPLS-TP re-use a subset of
  MPLS base functions
NEW
  MPLS-TP re-uses a subset of
  MPLS base functions

- - - -

Section 1.1

OLD
  MPLS-TP extended current MPLS OAM
  functions
NEW
  MPLS-TP extended previous MPLS OAM
  functions

---

Why do you consider use of RFC 2119 language to be appropriate in this
Informational document? All I could find was an instance of "MUST" that
you have inherited from RFC 5654. I think you could usefully tidy this
up.

---

There are too many acronyms used in Section 1 without expansion.

---

Section 1.2

I think Henry Yu asked for you to change his affiliation.

---

s/2. Terminologies/2. Terminology/

---

Please clean up Section 2 to remove those acronyms not actually used in
the document. For example, APS, DM, SRLG. You'll need to do a search and
destroy operation. On the other hand, please search the document for
other acronyms such as MSTP.

Please also decide whether G-ACH or G-ACh.

---

Section 3 seems a bit of a muddle. Details below, but this discussion
makes me wonder what the purpose of Section 3 is. The function of
MPLS-TP is well-defined in other documents. By summarising it here you
risk leaving out key pieces, and may give the wrong impression about the
details. It may be better to cut out this section and leave the document
to focus on the uses cases and network design.

- - - -

Section 3.2

  MPLS-TP extended the LSP support from unidirectional to both bi-
  directional unidirectional support.

The implication here is that there is something different in the MPLS
data plane in MPLS-TP to support bidirectional LSPs. But I don't think
there is. As far as the data plane is concerned, there is no difference
between two unidirectional LSPs and one bidirectional LSP.

- - - -

Section 3.3

I don't think that the use of an NMS for static provisioning is a
"control plane option". Maybe if you retitled the section as
"Provisioning". But anyway, I don't see why the ACH is mentioned in
this section.

---

The whole of the substantial Section 5.7 amounts to "In MPLS-TP, it is
best to provision LSPs with low or zero Relative Delay Time. But there
is no discussion of what this means for an MPLS-TP deployment.

Furthermore the section ends with...

  More discussion will be added on how to manage the Relative delay
  time.

...and this does not convince me that the document is complete.

---

Section 6

I would expect this document to examine the security requirements of the
different use cases. When is it necessary to use the security tools
developed and discussed in the two referenced documents?

---

Could you please split the Authors' Addresses into two sections.
Authors' Addresses to match those on the front page, and
Contributors' Addresses to capture all the others.

Where does Section 1.2 sit with respect to the Authors and
Contributors? Do you really need Section 1.2?

---

s/10.    Author's Addresses/10.    Authors' Addresses/

(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?

  The MPLS working group request that:

            MPLS-TP Applicability; Use Cases and Design
          draft-ietf-mpls-tp-use-cases-and-design-02.txt

  is published as an Informational RFC.

  This documentdoes not specify a protocol but provides case studies
  and network design considerations for Multiprotocol Label Switching
  Transport Profile (MPLS-TP) and is thus intended to be published as
  an informational RFC.


(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

  This document provides applicability, use case studies and network
  design considerations for Multiprotocol Label Switching Transport
  profile (MPLS-TP).

  In the recent years, MPLS-TP has emerged as the technology of choice
  for the new generation of packet transport. Many service providers
  (SPs) are working to replace the legacy transport technologies, e.g.
  SONET/SDH, TDM, and ATM technologies, with MPLS-TP for packet
  transport, in order to achieve higher efficiency, lower operational
  cost, while maintaining transport characteristics.

  The use cases for MPLS-TP include Metro Ethernet access and
  aggregation, Mobile backhaul, and packet optical transport. The
  design considerations discussed in this documents ranging from
  operational experience; standards compliance; technology maturity;
  end-to-end forwarding and OAM consistency; compatibility with
  IP/MPLS networks; multi-vendor interoperability; and optimization
  vs. simplicity design trade off discussion. The general design
  principle is to provide reliable, manageable, and scalable transport
  solutions.



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 has a strong support in the working group
  and has been well reviewed.

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?

  This an informational document, it presents some use-cases
  and provides design guidelines, but it is not possible to say that
  there are implementations.
  The document have had the review that is needed, the working
  group last call was brought to the attention of SG15 in
  ITU-T.


Personnel



  Who is the Document Shepherd? Who is the Responsible Area
  Director?
 
  Loa Andersson is the document shepherd.

  Adrian Farrel is/will be the responsible AD.



(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 have reviewed the document several times,
  e.g. when it was polled to become a wg document and at the wg last
  call, at at least one time between these two wg wide reviews.
  The 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? 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 such 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.

  There are no IPRs filed against this document.
  Before the working group last call started the working group chairs
  sent a mail to the working group and the authors, asking any members
  of the working group whom were aware of IPRs to speak up and requiring the
  authors either to indicate if they were aware of IPRs or say that they
  were not.



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

  There are no IPR filed for this document.



(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 working group is behind this document. It has been well discussed
  and reviewed as part of the MPLS-TP discussion. 



(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 such threats.


(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 idnits-tool flags three "problems"

  1. one line is 72 characters long
  2. one page is 59 rows long
  3. the idnits-tool claims that the reference to RFC2119 is
      missing, although it is clearly there.
      RFC2119 is listed as an informative reference, that could
      be the problem.

  The authors will be required to fix this if a new version is
  need or it will be captured in a RFC Editors note.

  No other nits found.




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

  There are no such formal review criteria.

(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, all normative references are to existing RFCs.



(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 downward references.



(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 changes to existing RFCs.



(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).


  No request for IANA allocations.



(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.


  No request for IANA allocations.


(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.

  No formal language.