Border Gateway Protocol - Link State (BGP-LS) Extensions for Segment Routing
draft-ietf-idr-bgp-ls-segment-routing-ext-18

[Ballot comment]
* Section 2.3.3.

I think the figure should say "4 or 16 octet Router-ID" instead of "4 or 6 octet Router-ID" as the IPv6 router ID will be 16 octets long

[Ballot comment]
Thanks for the work that everyone did on this document. I have only one
very minor comment.

§2.1.2:

>    Reserved: 1 octet that SHOULD be set to 0 and MUST be ignored on
>    receipt.

Making this a "SHOULD" rather than a "MUST" seems like it might interfere with
any future attempts to use this field, since compliant implementations might
have set the byte to arbitrary values.

This comment applies to other "reserved" fields in this document.

[Ballot comment]
Just an absolute nit in Section 1:

  A segment can
  represent any instruction; topological or service-based.

The semicolon is the wrong punctuation here.  A colon would work, as would a comma or a dash.

[Ballot comment]
-15

I agree with Mirja that mentioning the scope earlier in the document
would be helpful (but will follow the discussion in her ballot thread).
Basically, even though the SR Architecture is clear about the scope
being limited to a trusted administrative domain, it's still helpful to
remind the reader briefly at the start of the document that there is
some expectation of trust to all participants receiving this
information, and that it is not expected to leave into the broader
Internet or generic BGP peers.

Section 1

  When Segment Routing is enabled in an IGP domain, segments are
  advertised in the form of Segment Identifiers (SIDs).  The IGP link-
  state routing protocols have been extended to advertise SIDs and
  other SR-related information.  IGP extensions are described in: IS-IS
  [I-D.ietf-isis-segment-routing-extensions], OSPFv2
  [I-D.ietf-ospf-segment-routing-extensions] and OSPFv3
  [I-D.ietf-ospf-ospfv3-segment-routing-extensions].  [...]

nit: I think "described for" is more appropriate than "described in",
which might suggest to the reader that these are part of the core
protocols.

Section 2.1.1

      Length: Variable.  Either 3 or 4 depending whether the value is
      encoded as a label or as an index/SID.

nit: I think the secdir reviewer's concern might be alleviated by
spelling these constants as 0x0003 and 0x0004.

Section 2.1.2

Are the "SID/Label sub-TLV N" fields actually variable length?  The
description seems to be saying that we can only use the "label" variant
encoding, which makes the overall length of the sub-TLV 7 bytes, always.

      Flags: 1 octet of flags as defined in
      [I-D.ietf-isis-segment-routing-extensions] for IS-IS.  The flags
      are not currently defined for OSPFv2 and OSPFv3 and SHOULD be set
      to 0 and MUST be ignored on receipt.

I agree with the other reviewers that the SHOULD here is surprising.
Perhaps "Until the specification of flag value usage for OSPFv2 and/or
OSPFv3 is defined, the flags MUST be set to zero and ignored on
receipt"?

The case for Reserved seems even more clear to mandate setting to zero.

Section 2.1.3

Do the algorithm values need to appear in any specific order?
The note about the maximum length being 256 seems to imply that
duplicates are not expected, but I do not see any specific text
forbidding them.

Section 2.1.4

[Same comments as Section 2.1.2 about variable length sub-TLVs, and
SHOULD/MUST]

Section 2.2.1

  The Adjacency SID TLV is used in order to advertise information
  related to an Adjacency SID.  This information is derived from Adj-
  SID sub-TLV of IS-IS [I-D.ietf-isis-segment-routing-extensions],
  OSPFv2 [I-D.ietf-ospf-segment-routing-extensions] and OSPFv3
  [I-D.ietf-ospf-ospfv3-segment-routing-extensions].

nit: I think this should be "Adj-SID sub-TLVs" plural.

      Weight: 1 octet carrying the weight used for load-balancing
      purposes.

Maybe reference RFC 8402 for the weight semantics?  (Otherwise we have
to guess whether a larger value means to send more traffic vs. less
traffic.)

[Same comment about SHOULD/MUST for Reserved]

Section 2.2.2

[same comment about Weight and SHOULD/MUST for Reserved]

Do we want some IANA considerations and/or regisitry modifications to
provide for any future BGP-LS Attribute TLVs that might be defined and
be appropriate to include as sub-TLVs of the L2 Bundle Member Attribute
TLV?

Section 2.3.1

[same comment about SHOULD/MUST for Reserved]

Section 2.3.3

The figure says "4 or 6 octet Router-ID"; should that bt "4 or 16" to
match the body text?

Section 2.3.4

[same comment about SHOULD/MUST for Reserved]

It's a little weird to blandly cite the OSPF document for the Range Size
definition and expect that to plainly transfer over to the IS-IS case as
well.  (Also, the linked document has three different usages for "Range
Size"; I assume we mean the one in Section 4, "OSPF Extended  Prefix
Range TLV", since it's the right width, but it might be worth stating
explicitly.)

I didn't take the time to try to convince myself that the sub-TLV usage
for prefix-to-SID mappings matches up with the statement that the length
is "11 or 12 depending on Label or Index encoding of the SID", but I
think the TLV overhead would push the length larger than 12.

Section 5

The links for "required security and authentication mechanisms" are a
little surprising, as those documents are the segment-routing-extensions
documents for IS-IS and OSPF, respectively, and do not define the
mechamisms themselves, rather referring to other document for  the
details of the security mechanisms.  Furthermore, there seem to only be
SHOULD-level requirements for authentication mechanisms, and only in
certain cases (and only in the OSPFv2 document).  So to say "the required
mechanisms" here seems misleading, in that the set of *required*
mechanisms seems to be the empty set.

I always have a hard time accepting statements about "present no
additional risk"; we are going from presenting "generic"
link-state/prefix/node information across the BGP-LS domain to
additionally presenting information about the SR topology and segment
location/identifiers.  So, one might concoct a scenario in which an
attacker can learn about the internal SR configuration/topology based on
the information conveyed by the mechanisms in  this document, which is
in some sense an "additional risk".  That said, it is probably a minor
one, given the expected scope of distribution.

[Ballot comment]
I'd like to strongly support Mirja's comment -- having this buried in the Security Considerations section makes it easy to miss, and that does set the tone for the rest of the document..

Also, thank you for this document -- it is nice to see this finally getting out the door. Special thanks for the Manageability Considerations section

[Ballot comment]
(1) Section 2.0.  Does the sentence, “This document adds additional BGP-LS Attribute TLVs in order to encode SR information” imply that this document should explicitly update RFC7752?

(2) Add more detailed citations
-- Section 2.x.  Section 2.1.x.  When citing a reference to explain a given TLV/sub-TLV, consider adding the relevant section number to improve readability.  For example:

OLD: Section 2.1.1, IS-IS, as defined by the SID/Label sub-TLV in [I-D.ietf-isis-segment-routing-extensions].

NEW: Section 2.1.1, IS-IS, as defined by the SID/Label sub-TLV in Section 3.2 of [I-D.ietf-isis-segment-routing-extensions].

-- Section 2.1.2  Per the octet of flags, please specify the specific section number of [I-D.ietf-isis-segment-routing-extensions].

-- Section 2.2.*.  Consider adding the appropriate section number in the references when described the flags field.

(3) Section 2.1.4.  Per “SID/Label sub-TLV (as defined in Section 2.1.1) which encodes the first label in the range”, why is this just the first label?  Isn’t there the potential of a series of labels each in a distinct SID/Label sub-TLV?

(4) Section 2.2.2.  Is there a reference to explain the semantics of the weight field?

(5) Section 2.3.1.  Is there a reference to explain the semantics of the algorithm field?

(6) Editorial Nits:
-- Section 2.1.1.  Missing word:
s/The TLV and has the following format:/
/The TLV and sub-TLV has the following format:/

-- Section 2.1.5.  Typo.  s/a unsigned/an unsigned/

[Ballot comment]
There is the following statement on the applicability of this approach in the security consideration section:

“The SR traffic engineering
  policies using the SIDs advertised via BGP-LS are expected to be used
  entirely within this trusted SR domain (e.g. between multiple AS/
  domains within a single provider network).  Therefore, precaution is
  necessary to ensure that the SR information advertised via BGP-LS
  sessions is limited to consumers in a secure manner within this
  trusted SR domain.”

As this is every essential to the scope of the document I would like to see this earlier in the document, e.g. in the intro, and own applicability section, or even in the abstract.


One additional comment on the shepherd write-up:
I find the write-up a bit confusing but I assume that this document has wg consensus, even though it might be rough. There is a request to the IESG to make a judgment if this approach should be taken forward in general. However, if there are no technical or security concerns here and there is wg consensus, I don’t think I understand this request; expect this is not seen as covered by the charter, however, I don’t think this is indicated in the shepherd write-up.

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

The IANA Functions Operator has completed its review of draft-ietf-idr-bgp-ls-segment-routing-ext-14. If any part of this review is inaccurate, please let us know.

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

In the BGP-LS Node Descriptor, Link Descriptor, Prefix Descriptor, and Attribute TLVs registry on the Border Gateway Protocol - Link State (BGP-LS) Parameters registry page located at:

https://www.iana.org/assignments/bgp-ls-parameters/

we'll update the references for the following TLV codepoints to [ RFC-to-be ].

+----------------+-----------------------------+
| TLV Code Point | Description |
+----------------+-----------------------------+
| 1034 | SR Capabilities |
| 1035 | SR Algorithm |
| 1036 | SR Local Block |
| 1037 | SRMS Preference |
| 1099 | Adjacency SID |
| 1100 | LAN Adjacency SID |
| 1158 | Prefix SID |
| 1159 | Range |
| 1161 | SID/Label |
| 1170 | Prefix Attribute Flags |
| 1171 | Source Router-ID |
| 1172 | L2 Bundle Member Attributes |
+----------------+-----------------------------+

The IANA Functions 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 meant 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 2019-05-23):

From: The IESG
To: IETF-Announce
CC: idr@ietf.org, Susan Hares , idr-chairs@ietf.org, aretana.ietf@gmail.com, draft-ietf-idr-bgp-ls-segment-routing-ext@ietf.org, shares@ndzh.com
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (BGP Link-State extensions for Segment Routing) to Proposed Standard


The IESG has received a request from the Inter-Domain Routing WG (idr) to
consider the following document: - 'BGP Link-State extensions for Segment
Routing'
  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 2019-05-23. 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


  Segment Routing (SR) allows for a flexible definition of end-to-end
  paths by encoding paths as sequences of topological sub-paths, called
  "segments".  These segments are advertised by routing protocols e.g.
  by the link state routing protocols (IS-IS, OSPFv2 and OSPFv3) within
  IGP topologies.

  This draft defines extensions to the BGP Link-state address-family in
  order to carry segment routing information via BGP.





The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-idr-bgp-ls-segment-routing-ext/

IESG discussion can be tracked via
https://datatracker.ietf.org/doc/draft-ietf-idr-bgp-ls-segment-routing-ext/ballot/


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

=== AD Review of draft-ietf-idr-bgp-ls-segment-routing-ext-11 ===
https://mailarchive.ietf.org/arch/msg/idr/G_k3hBm4-K5O6onooVc6yuCdz6g

Dear authors:

I just finished my review of this document -- please see inline comments/questions.

In general, I think that there is more work needed in at least two fronts:

(1) Consistency in the specification of the new TLVs.  Most of the descriptions point at other documents, but they don't do so in a consistent manner: some at the start of the section, others when pointing at the values, etc.  Please be consistent!  Given that §2.4/2.5 already have a summary, I personally find the information in the individual sections redundant.  Instead of a statement at the start of a section, I prefer you to be specific about the values -- see §2.1.2 for an example.

Please note that most of my comments related to the specification of the TLVs apply to multiple sections, not just the one where I made them.  I pointed this out in most cases, but may have missed some.


(2) Error Handling.  As has been discussed on the list (for example in [1], [2] and [3]), rfc7752 could use enhancements as it relates to considering error handling with applications such as SR, and in general.  Those issues don't need to be fixed in this document, but I would like to see in this document some text about the potential effect: maybe in terms of the effect than an error might have from an operations or management point of view... See my comments below for specifics.  Again, not looking for this document to "fix" BGP-LS, but to consider the effect on the expected function a controller might have, as described in the Introduction.

[1] https://mailarchive.ietf.org/arch/msg/idr/Tm0vlu-ECSnIAyO1byj68AJm2XU
[2] https://mailarchive.ietf.org/arch/msg/idr/0qsjuVaEhroKInHZMohP6HnsWd8
[3] https://mailarchive.ietf.org/arch/msg/idr/-CZGAiC8D3KogLnUs6ClW_KlU24


Thanks!

Alvaro.


[Line numbers come from idnits.]

...
27 Requirements Language

29   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
30   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
31   document are to be interpreted as described in RFC 2119 [RFC2119].

[major] Please use the rfc8174 template.


...
99 1.  Introduction
...
110   Two types of IGP segments are defined, Prefix segments and Adjacency
111   segments.  Prefix segments, by default, represent an ECMP-aware
112   shortest-path to a prefix, as per the state of the IGP topology.
113   Adjacency segments represent a hop over a specific adjacency between
114   two nodes in the IGP.  A prefix segment is typically a multi-hop path
115   while an adjacency segment, in most of the cases, is a one-hop path.
116   [RFC8402].

[nit] rfc8402 defines more than 2 IGP segments.

[nit] s/one-hop path. [RFC8402]./one-hop path [RFC8402].

118   When Segment Routing is enabled in a IGP domain, segments are
119   advertised in the form of Segment Identifiers (SIDs).  The IGP link-
120   state routing protocols have been extended to advertise SIDs and
121   other SR-related information.  IGP extensions are described in: IS-IS
122   [I-D.ietf-isis-segment-routing-extensions], OSPFv2
123   [I-D.ietf-ospf-segment-routing-extensions] and OSPFv3
124   [I-D.ietf-ospf-ospfv3-segment-routing-extensions].  Using these
125   extensions, Segment Routing can be enabled within an IGP domain.

[nit] s/a IGP domain/an IGP domain

127                           +------------+
128                           |  Consumer  |
129                           +------------+
130                                 ^
131                                 |
132                                 v
133                       +-------------------+
134                       |    BGP Speaker    |        +-----------+
135                       | (Route-Reflector) |        | Consumer  |
136                       +-------------------+        +-----------+
137                             ^  ^  ^                      ^
138                             |  |  |                      |
139             +---------------+  |  +-------------------+  |
140             |                  |                      |  |
141             v                  v                      v  v
142       +-----------+      +-----------+            +-----------+
143       |    BGP    |      |    BGP    |            |    BGP    |
144       |  Speaker  |      |  Speaker  |    . . .    |  Speaker  |
145       +-----------+      +-----------+            +-----------+
146             ^                  ^                        ^
147             |                  |                        |
148             IGP                IGP                      IGP

150                   Figure 1: Link State info collection

[nit] Maybe move this Figure so it is closer to where it is referenced.

...
159   In order to address the need for applications that require
160   topological visibility across IGP areas, or even across Autonomous
161   Systems (AS), the BGP-LS address-family/sub-address-family have been
162   defined to allow BGP to carry Link-State information.  The BGP
163   Network Layer Reachability Information (NLRI) encoding format for
164   BGP-LS and a new BGP Path Attribute called the BGP-LS attribute are
165   defined in [RFC7752].  The identifying key of each Link-State object,
166   namely a node, link, or prefix, is encoded in the NLRI and the
167   properties of the object are encoded in the BGP-LS attribute.
168   Figure 1 describes a typical deployment scenario.  In each IGP area,
169   one or more nodes are configured with BGP-LS.  These BGP speakers
170   form an IBGP mesh by connecting to one or more route-reflectors.
171   This way, all BGP speakers (specifically the route-reflectors) obtain
172   Link-State information from all IGP areas (and from other ASes from
173   EBGP peers).  An external component connects to the route-reflector
174   to obtain this information (perhaps moderated by a policy regarding
175   what information is or isn't advertised to the external component).

[minor] The way that the propagation of information can be controlled by policy is important.  Please make sure that the text is clear in the fact that the discussion above is referencing rfc7752 (and that the reference to it is not just about the encodings).

177   This document describes extensions to BGP-LS to advertise the SR
178   information.  An external component (e.g., a controller) then can
179   collect SR information from across an SR domain and construct the
180   end-to-end path (with its associated SIDs) that need to be applied to
181   an incoming packet to achieve the desired end-to-end forwarding.
182   Here the SR domain is defined as a single administrative domain that
183   may be comprised of a single AS or multiple ASes under consolidated
184   global SID administration.

[nit] s/under consolidated/under a consolidated

[major] Please don't redefine "SR domain".  The definition above is not the same as what rfc8402 says (in §2).  Easy fix: simply put a reference to rfc8402 next to the first mention of "SR domain", and delete that last sentence.

186 2.  BGP-LS Extensions for Segment Routing

188   This document defines SR extensions to BGP-LS and specifies the TLVs
189   and sub-TLVs for advertising SR information within the BGP-LS
190   Attribute.  Section 2.4 and Section 2.5 illustrates the equivalent
191   TLVs and sub-TLVs in IS-IS, OSPFv2 and OSPFv3 protocols.

[nit] "illustrates" sounds like giving examples of equivalent TLVs.  But I think that the tables don't show examples, they show/point to the corresponding TLVs.  Perhaps use a different word...


...
200   Some of the TLVs defined in this document contain fields (e.g. flags)
201   whose semantics need to be interpreted accordingly to the respective
202   underlying IS-IS, OSPFv2 or OSPFv3 protocol.  The receiver of the
203   BGP-LS update for any of the NLRIs MUST check the Protocol-ID of the
204   NLRI and refer to the underlying protocol specification in order to
205   parse such fields.  The individual field descriptions in the sub-
206   sections below point to the relevant underlying protocol
207   specifications for such fields.

[major] "The receiver of the BGP-LS update for any of the NLRIs MUST check the Protocol-ID of the NLRI and refer to the underlying protocol specification in order to parse such fields."  This text is a general statement ("for any of the NLRIs") that seems to want to Update rfc7752, where Protocol-ID is defined...but I don't think that is the intent, right?  Note that rfc7752 doesn't explicitly mandate that the "receiver...refer to the underlying protocol specification" -- it just implies it when talking about the Opaque TLVs.

IOW, this seems like a significant change as related to other BGP-LS specs.

Note also that §5 (Manageability Considerations) has the following text, which I think is in contradiction of the one above:

...
                      ...                The semantic or content
  checking for the TLVs specified in this document and their
  association with the BGP-LS NLRI types or their BGP-LS Attribute is
  left to the consumer of the BGP-LS information (e.g. an application
  or a controller) and not the BGP protocol.

  ...              The handling of semantic or content errors by the
  consumer would be dictated by the nature of its application usage and
  hence is beyond the scope of this document.

209 2.1.  Node Attributes TLVs

211   The following Node Attribute TLVs are defined:

213               +-----------------+----------+---------------+
214               | Description    | Length  |      Section |
215               +-----------------+----------+---------------+
216               | SID/Label      | variable | Section 2.1.1 |
217               | SR Capabilities | variable | Section 2.1.2 |
218               | SR Algorithm    | variable | Section 2.1.3 |
219               | SR Local Block  | variable | Section 2.1.4 |
220               | SRMS Preference | variable | Section 2.1.5 |
221               +-----------------+----------+---------------+

223                       Table 1: Node Attribute TLVs

[minor] It would be nice if the table also contained the TLV Type.  This comment applies to other similar tables.

[minor] §2.1.2/2.1.3 use a "-" in the name of the TLV.  Please be consistent as both versions are used throughout the document.

[nit] Yes, the length is variable, but in some cases the possible values are known.  For example, the length of the SID/Label sub-TLV can only be 3 or 4.  Consider indicating that.  OTOH, I don't see why indicating the Length is significant at this point -- IOW, I would even suggest removing that column.

225   These TLVs can ONLY be added to the BGP-LS Attribute associated with
226   the Node NLRI that originates the corresponding underlying IGP TLV/
227   sub-TLV described below.

[minor] "the Node NLRI that originates the corresponding underlying IGP..."  The Node NLRI doesn't originate anything...it describes the IGP node that originates something...  Please be specific.

[major] The text above sounds as if you want to mandate something...  Writing "ONLY" in caps doesn't have a Normative effect.  Should there be a "MUST" somewhere?  Or perhaps soften a little: s/can ONLY/should only

The next question is: what if they are added somewhere else?  There doesn't seem to be a way for the receiver to know if the TLVs are associated with the correct Node NLRI...  I'm guessing that all the receiver can do is assume that the TLV is referring to the right node...

From the text, I'm assuming that the use is intended to be limited to the Node NLRI.  Unfortunately, rfc7752 doesn't specify actions to be taken if that is not the case.

This comment applies to other places where the "ONLY be added" phrase exists.


229 2.1.1.  SID/Label Sub-TLV

231   The SID/Label TLV is used as sub-TLV by the SR-Capabilities
232   (Section 2.1.2) and SRLB (Section 2.1.4) TLVs and has the following
233   format:

[nit] s/used as sub-TLV/used as a sub-TLV

[minor] This is the first time that SRLB is used in this document, please use the extended version here:  s/SRLB/SR Local Block (SRLB)

...
245       Type: TBD, see Section 4.

[minor] The code points have already been assigned (early allocation).  Please change "TBD" for the actual values.

247       Length: Variable, 3 or 4.

[nit] The Length is really not variable...it's 3 or 4.

...
254       The receiving router MUST ignore the SID/Label sub-TLV if the
255       length is other then 3 or 4.

[major] If the sub-TLV is ignored, the information in the SR-Capabilities or SR Local Block TLVs will be incomplete (at best).  What is the potential impact of that?  Is the received information still useful?  Should other actions be taken?

257 2.1.2.  SR-Capabilities TLV

259   The SR-Capabilities TLV is used in order to advertise the node's SR
260   Capabilities including its Segment Routing Global Base (SRGB)
261   range(s).  In the case of IS-IS, the capabilities also include the
262   IPv4 and IPv6 support for SR-MPLS forwarding plane.  This information
263   is derived from the protocol specific advertisements.

[nit] s/support for SR-MPLS forwarding plane/support for the SR-MPLS forwarding plane

265   o  IS-IS, as defined by the SR-Capabilities sub-TLV in
266       [I-D.ietf-isis-segment-routing-extensions].

268   o  OSPFv2/OSPFv3, as defined by the SID/Label Range TLV in
269       [I-D.ietf-ospf-segment-routing-extensions] and
270       [I-D.ietf-ospf-ospfv3-segment-routing-extensions].

[minor] The text above, pointing at the individual IGP specs is present in many of the descriptions for the TLVs, but not all.  Sections 2.4/2.5 have tables that also point at the equivalent TLVs.  I'm looking for consistency: either indicate in each section where the information is derived from, or not.  Given that §2.4/2.5 already have a summary, I personally find the information (like the one above) in the individual sections redundant.  Instead of the statement above, I prefer you to be specific about the values described below -- for example, when describing the Range Size field below, you could say something like this:

OLD>
  Range Size: 3 octet value indicating the number of labels in
  the range.

NEW>
  Range Size: 3 octet value indicating the number of labels in
  the range.  The value and characteristics of this field are derived from the Range field in the SR-Capabilities sub-TLV in [I-D.ietf-isis-segment-routing-extensions], or from the Range Size field in the SID/Label Range TLV in [I-D.ietf-ospf-segment-routing-extensions] and [I-D.ietf-ospf-ospfv3-segment-routing-extensions].

Note that doing it this way saves you the need to define the characteristics of each field (because even if the values are derived, the TLVs here are new).

This comment obviously applies to all similar instances in the document.

272   The SR Capabilities TLV has following format:

[nit] s/has following format/has the following format


...
290       Length: Variable.

[major] Yes, it's variable, but it has to be at least 12.  What should a router do if the length is < 12?  After that, there are only specific valid lengths: 12, 13, 19, 21, etc.  What if the length is not one of those values?

I couldn't find guidance in rfc7752.  The closest statement is from §6.2.2 (Fault Management), where one of the "checks for determining if a message is malformed...Does any fixed-length TLV correspond to the TLV Length field in this document?"  This TLV is not fixed-length, but the possibilities are finite.

Note that rfc7752 says that if the length is not the expected one, then the whole BGP-LS attribute is discarded.  For this specific case, it means that the controller wouldn't have complete knowledge of the network, even if the information derived from the IGP is correct...

This comment applies to other similar instances.

292       Flags: 1 octet of flags as defined in
293       [I-D.ietf-isis-segment-routing-extensions].

[major] When the BGP-LS information comes from OSPF, how should the flags be interpreted?  There is no indication in the corresponding OSPF drafts of "IPv4 and IPv6 support for SR-MPLS" -- should the bits always be unset?


...
300         Range Size: 3 octet value indicating the number of labels in
301         the range.

[nit] s/labels/labels or SIDs

[major] What numbers are valid in the Range Size field?  Can it be 0?  Take a look above at my comments about derived values.

303         SID/Label sub-TLV (as defined in Section 2.1.1) which encodes
304         the first label in the range.

[nit] s/first label/first label or SID


...
339 2.1.4.  SR Local Block TLV
...
380       Flags: 1 octet of flags.  None are defined at this stage.

[major] Only the corresponding ISIS sub-TLV has Flags defined -- and I realize that the text above is the same as in draft-ietf-isis-segment-routing-extensions.  I think you really don't want this field to evolve independently.  IOW, please use a description like the you used for the Flags in the SR-Capabilities TLV.


...
393 2.1.5.  SRMS Preference TLV
...
427   The use of the SRMS Preference TLV is defined in
428   [I-D.ietf-isis-segment-routing-extensions],
429   [I-D.ietf-ospf-segment-routing-extensions] and
430   [I-D.ietf-ospf-ospfv3-segment-routing-extensions].

[major] This document only defines how to carry information in BGP-LS, not what to do with it.  IOW, I think that the last paragraph is not needed, it is out of scope of this document...

432 2.2.  Link Attribute TLVs

434   The following Link Attribute TLVs are are defined:

436   +----------------------------------------+----------+---------------+
437   | Description                            |  Length |      Section |
438   +----------------------------------------+----------+---------------+
439   | Adjacency Segment Identifier (Adj-SID) | variable | Section 2.2.1 |
440   | TLV                                    |          |              |
441   | LAN Adjacency Segment Identifier (Adj- | variable | Section 2.2.2 |
442   | SID) TLV                              |          |              |
443   | L2 Bundle Member TLV                  | variable | Section 2.2.3 |
444   +----------------------------------------+----------+---------------+

446                       Table 2: Link Attribute TLVs

[minor] The names used above don't match the names used in the sections below.

...
452   For a LAN, normally a node only announces its adjacency to the IS-IS
453   pseudo-node (or the equivalent OSPF Designated and Backup Designated
454   Routers)[I-D.ietf-isis-segment-routing-extensions].  The LAN
455   Adjacency Segment TLV allows a node to announce adjacencies to all
456   other nodes attached to the LAN in a single instance of the BGP-LS
457   Link NLRI.  Without this TLV, the corresponding BGP-LS link NLRI
458   would need to be originated for each additional adjacency in order to
459   advertise the SR TLVs for these neighbor adjacencies.

[minor] This paragraph maybe fits better in §2.2.2.


461 2.2.1.  Adjacency SID TLV
...
482       Flags. 1 octet field of following flags as defined in
483       [I-D.ietf-isis-segment-routing-extensions],
484       [I-D.ietf-ospf-segment-routing-extensions] and
485       [I-D.ietf-ospf-ospfv3-segment-routing-extensions].

NEW>
  Flags: 1 octet field.  The value corresponds to the Flags specified for the
  Adj-SID Sub-TLV in [I-D.ietf-isis-segment-routing-extensions],
  [I-D.ietf-ospf-segment-routing-extensions] or
  [I-D.ietf-ospf-ospfv3-segment-routing-extensions].

487       Weight: Weight used for load-balancing purposes.

[minor] Similar to the above text...

489       Reserved: 2 octets that SHOULD be set to 0 and MUST be ignored on
490       receipt.

492       SID/Index/Label: Label or index value depending on the flags
493       setting as defined in [I-D.ietf-isis-segment-routing-extensions],
494       [I-D.ietf-ospf-segment-routing-extensions] and
495       [I-D.ietf-ospf-ospfv3-segment-routing-extensions].

[minor] Similar text here too...


497 2.2.2.  LAN Adjacency SID TLV
...
[major] The OSPF Neighbor ID / IS-IS System-ID field is not defined.


542 2.2.3.  L2 Bundle Member

[nit] s/L2 Bundle Member/L2 Bundle Member Attribute TLV

544   The L2 Bundle Member Attribute TLV identifies an L2 Bundle Member
545   link which in turn is associated with a parent L3 link.  The L3 link
546   is described by the Link NLRI defined in [RFC7752] and the L2 Bundle
547   Member Attribute TLV is associated with the Link NLRI.  The TLV MAY
548   include sub-TLVs which describe attributes associated with the bundle
549   member.  The identified bundle member represents a unidirectional
550   path from the originating router to the neighbor specified in the
551   parent L3 Link.  Multiple L2 Bundle Member Attribute TLVs MAY be
552   associated with a Link NLRI.

[minor] "identifies an L2 Bundle Member link...The identified bundle member".  Are we talking about a link or just the members?

...
574       L2 Bundle Member Descriptor: A Link Local Identifier as defined in
575       [RFC4202].

[major] From the text, it looks like this information is not something that is learned from the IGP, which is then just transported by BGP-LS (just like the rest of the TLVs in this document), but table 5 points at draft-ietf-isis-l2bundles.  Why is draft-ietf-isis-l2bundles not used to describe this TLV?

[major] rfc4202 is not IS-IS-specific.  What about OSPF?  I note that rfc4203 defines OSPF extensions that include the Link Local Identifier, so this concept is not foreign to it.

577   Link attributes for L2 Bundle Member Links are advertised as sub-TLVs
578   of the L2Bundle Member Attribute TLV.  The sub-TLVs are identical to
579   existing BGP-LS TLVs as identified in the table below.

[nit] s/L2Bundle/L2 Bundle


...
633 2.3.1.  Prefix-SID TLV
...
[major] draft-ietf-ospf-segment-routing-extensions also includes the MT-ID in the Prefix SID Sub-TLV.  Is that not needed by a controller?

691 2.3.2.  Prefix Attribute Flags TLV
...
711       Length: variable.

[minor] The length of the flags fields in rfc7794/rfc7684 are both one octet long.  Can this length be made fixed?

[major] I could not find a Flags field for OSPFv3 in rfc5340.

[minor] From Table 7, it seems that the reference to rfc8362 points to the "Prefix Options Field", is that correct?

713       Flags: a variable length flag field (according to the length
714       field).  Flags are routing protocol specific and are to be parsed
715       as below:

717       *  IS-IS flags are defined in [RFC7794]

719       *  OSPFv2 flags are defined in [RFC7684]

721       *  OSPFv3 flags map to the Prefix Options field defined in
722         [RFC7794] and extended via [RFC8362]

[nit] The text at the top of this section refers to rfc5340...

[major] rfc7794 only talks about IS-IS, not OSPFv3.


724 2.3.3.  Source Router Identifier (Source Router-ID) TLV

726   The Source Router-ID TLV contains the IPv4 or IPv6 Router-ID of the
727   originator of the Prefix.  For IS-IS protocol this is as defined in
728   [RFC7794].  The Source Router-ID TLV may be used to carry the OSPF
729   Router-ID of the prefix originator.

[major] Reference for OSPF?  Only "may"??

[major] rfc7752 defines the IGP Router-ID TLV to carry the same information.  What is the relationship between these two TLVs?  Since the IGP Router-ID TLV is mandatory, are there cases where this one may not be needed?


...
745       Length: 4 or 16.

[major] OSPF always uses a 32-bit number.  IOW, the length is fixed for OSPF.

...
749 2.3.4.  Range TLV

751   The range TLV is used in order to advertise a range of prefix-to-SID
752   mappings as part of the Segment Routing Mapping Server functionality
753   [I-D.ietf-spring-segment-routing-ldp-interop], as defined in the
754   respective underlying IGP SR extensions
755   [I-D.ietf-ospf-segment-routing-extensions],
756   [I-D.ietf-ospf-ospfv3-segment-routing-extensions] and
757   [I-D.ietf-isis-segment-routing-extensions].  The Prefix-NLRI to which
758   the Range TLV is attached MUST be advertised as a non-routing prefix
759   where no IGP metric TLV (TLV 1095) is attached.

[major] What do you mean in the final sentence?  It sounds as if the IGP metric TLV and the Range TLV are mutually exclusive and should never be advertised together.  Is that it?  If so, what should the receiver do if they are?


761   The format of the Range TLV is as follows:

763     0                  1                  2                  3
764     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
765   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
766   |            Type              |            Length            |
767   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
768   |    Flags    | Reserved      |            Range Size        |
769   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
770   //                          sub-TLVs                          //
771   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

773   where:

[nit] That "where" should be after the Figure title.

775                         Figure 2: Range TLV format


...
[minor] As will all the other sections, please be consistent and fold the sub-sections below into the description above.

804 2.3.4.1.  Advertisement Procedure for OSPF

806   The OSPFv2/OSPFv3 Extended Prefix Range TLV is encoded in the Range
807   TLV.  The flags of the Range TLV have the semantic mapped to the
808   definition in [I-D.ietf-ospf-segment-routing-extensions] section 4 or
809   [I-D.ietf-ospf-ospfv3-segment-routing-extensions] section 4.

811   Then the prefix-to-SID mapping from the OSPF Prefix SID sub-TLV is
812   encoded using the BGP-LS Prefix-SID TLV as defined in Section 2.3.1
813   with the flags set according to the definition in
814   [I-D.ietf-ospf-segment-routing-extensions] section 5 or
815   [I-D.ietf-ospf-ospfv3-segment-routing-extensions] section 5.

[major] The Extended Prefix Range TLV contains other fields not present here: AF, for instance.  The last paragraph seems to indicate that the prefix information will be in the BGP-LS Prefix-SID TLV, but that information doesn't come from the Extended Prefix Range TLV (and it doesn't include the AF).  What am I missing?

[major] The text above seems to imply that the Range TLV and the Prefix-SID TLV should always be included together.  Is that true?  If so, please make it more explicit.

817 2.3.4.2.  Advertisement Procedure for IS-IS

819   The IS-IS SID/Label Binding TLV, when used to signal mapping server
820   label bindings, is encoded in the Range TLV.  The flags of the Range
821   TLV have the sematic mapped to the definition in
822   [I-D.ietf-isis-segment-routing-extensions] section 2.4.1.

824   Then the prefix-to-SID mappings from the IS-IS Prefix SID sub-TLV is
825   encoded using the BGP-LS Prefix-SID TLV as defined in Section 2.3.1
826   with the flags set according to the definition in
827   [I-D.ietf-isis-segment-routing-extensions] section 2.4.4.1.

[major] Same questions (as above) related to the other fields in the SID/Label Binding TLV, and the relationship between the Range TLV and the Prefix-SID TLV.


829 2.4.  Equivalent IS-IS Segment Routing TLVs/Sub-TLVs
...
837   +---------------------------------------+----------+----------------+
838   | Description                          | Length  | IS-IS TLV/sub- |
839   |                                      |          | TLV            |
840   +---------------------------------------+----------+----------------+
841   | SR Capabilities                      | variable | 2 [1]          |
842   | SR Algorithm                          | variable | 19 [2]        |
843   | SR Local Block                        | variable | 22 [3]        |
844   | SRMS Preference                      | 1        | 19 [4]        |
845   | Adjacency Segment Identifier (Adj-    | variable | 31 [5]        |
846   | SID)                                  |          |                |
847   | LAN Adjacency Segment Identifier      | variable | 32 [6]        |
848   | (LAN-Adj-SID)                        |          |                |
849   | Prefix SID                            | variable | 3 [7]          |
850   | Range                                | variable | 149 [8]        |
851   | SID/Label TLV                        | variable | 1 [9]          |
852   | Prefix Attribute Flags                | variable | 4 [10]        |
853   | Source Router ID                      | variable | 11/12 [11]    |
854   | L2 Bundle Member TLV                  | variable | 25 [12]        |
855   +---------------------------------------+----------+----------------+

[major] Instead of using URIs, please put an explicit pointer to the RFC/ID (and if desired, the section)...and make sure that there are corresponding References.  If a document is referenced only in this table, then the Reference can be Informative.

[nit] For Tables 5-7: No need to use "TLV" in the description.

857           Table 5: IS-IS Segment Routing Extensions TLVs/Sub-TLVs

859 2.5.  Equivalent OSPFv2/OSPFv3 Segment Routing TLVs/Sub-TLVs
...
886           Table 6: OSPF Segment Routing Extensions TLVs/Sub-TLVs

[nit] s/OSPF/OSPFv2

[minor] The OSPF tables don't include the Source Router ID or the L2 Bundle Member TLVs.  Is there a reason for that, or just an oversight?

...
908 3.  Implementation Status

[nit] This section says nothing. :-(  At least a pointer to https://trac.ietf.org/trac/idr/wiki/draft-ietf-idr-bgp-ls-segment-routing-ext-implementations might be nice.  OR, you can just remove it.


...
943 4.  IANA Considerations

945   This document requests assigning code-points from the registry "BGP-
946   LS Node Descriptor, Link Descriptor, Prefix Descriptor, and Attribute
947   TLVs" based on table Table 8.  The column "IS-IS TLV/Sub-TLV" defined
948   in the registry does not require any value and should be left empty.

[major] The early allocation has already been done...so this document doesn't request assignment from IANA.  Please update.


...
977 5.  Manageability Considerations

979   This section is structured as recommended in [RFC5706].

981   The new protocol extensions introduced in this document augment the
982   existing IGP topology information that was distributed via [RFC7752].
983   Procedures and protocol extensions defined in this document do not
984   affect the BGP protocol operations and management other than as
985   discussed in the Manageability Considerations section of [RFC7752].
986   Specifically, the malformed attribute tests for syntactic checks in
987   the Fault Management section of [RFC7752] now encompass the new BGP-
988   LS Attribute TLVs defined in this document.  The semantic or content
989   checking for the TLVs specified in this document and their
990   association with the BGP-LS NLRI types or their BGP-LS Attribute is
991   left to the consumer of the BGP-LS information (e.g. an application
992   or a controller) and not the BGP protocol.

[nit] s/that was distributed/that is distributed

994   A consumer of the BGP-LS information is retrieving this information
995   from a BGP protocol component that is doing the signaling over a BGP-
996   LS session, via some APIs or a data model (refer Section 1 and 2 of
997   [RFC7752]).  The handling of semantic or content errors by the
998   consumer would be dictated by the nature of its application usage and
999   hence is beyond the scope of this document.  This document only
1000   introduces new Attribute TLVs and an error in them would result in
1001   only that specific attribute being discarded with an error log.

[nit] s/is retrieving this/retrieves this

[minor] "...retrieving this information...over a BGP-LS session, via some APIs or a data model (refer Section 1 and 2 of [RFC7752])."  I think that even mentioning that an API or data model can be used instead of BGP-LS is a stretch -- that is not how I interpret the initial sections in rfc7752 (which are just background sections), and there are no formal API/data model definition.

[major] "...new Attribute TLVs and an error in them would result in only that specific attribute being discarded with an error log."  According to rfc7752, this statement is true only for syntactic errors, not semantic ones.

Semantic errors ("left to the consumer", as mentioned above) means that the BGP-LS session can be used to transport trash (trash-in-trash-out).  Jeff Haas brought this up during the WGLC [4].  I agree (with the Chairs' conclusion) that this issue is bigger than this document -- but (because we don't have a current solution) I would like to see it mentioned somewhere as a potential issue (maybe in the Management or Security Considerations sections, your choice).

[4] https://mailarchive.ietf.org/arch/msg/idr/Yfp6WyqnRtMAOeZvSvK7rYCUkHg

[major] rfc7752 does mandate the use of "attribute discard" (rfc7606). I would really like to see a discussion (or at least a mention) around the fact that discarding an attribute may result in the receiver not having complete information.  In the case of SR, this implies that the controller may not have complete information to calculate the paths.

I think this is an issue bigger than this document, so I am not asking you to solve it...I'm just asking for the document to acknowledge that it exists and to mention what the potential impact may be.


1003   The extensions, specified in this document, do not introduce any new
1004   configuration or monitoring aspects in BGP or BGP-LS other than as
1005   discussed in [RFC7752].  The manageability aspects of the underlying
1006   SR features are covered by [I-D.ietf-spring-sr-yang],
1007   [I-D.ietf-isis-sr-yang] and [I-D.ietf-ospf-sr-yang].

[minor] While the Yang models have to do with management, there are no "manageability aspects of the underlying SR features" included there.

[major] Following the recommendations from rfc5706, a Fault Management section would be appropriate to include considerations related to the use of BGP-LS as a transport for SR information (given this is the first draft to propose it), and the possible errors mentioned here...  Again, not looking for solutions, just acknowledgement.


1009 6.  Security Considerations

1011   The new protocol extensions introduced in this document augment the
1012   existing IGP topology information that was distributed via [RFC7752].
1013   The Security Considerations section of [RFC7752] also applies to
1014   these extensions.  The procedures and new TLVs defined in this
1015   document, by themselves, do not affect the BGP-LS security model
1016   discussed in [RFC7752].

[nit] s/that was distributed/that is distributed

1018   BGP-LS SR extensions enable traffic engineering use-cases within the
1019   Segment Routing domain.  SR operates within a trusted domain (refer
1020   Security Considerations section in [RFC8402] for more detail) and its
1021   security considerations also apply to BGP-LS sessions when carrying
1022   SR information.The SR traffic engineering policies using the SIDs
1023   advertised via BGP-LS are expected to be used entirely within this
1024   trusted SR domain (e.g. between multiple AS/domains within a single
1025   provider network).  Therefore, precaution is necessary to ensure that
1026   the SR information collected via BGP-LS is limited to specific
1027   controllers or applications in a secure manner within this SR domain.

[nit] s/trusted domain (refer Security Considerations section in [RFC8402] for more detail)/trusted domain [RFC8402]

[nit] s/SR information.The SR traffic/SR information. The SR traffic

[major] "SR operates within a trusted domain...[RFC8402]...and its security considerations also apply to BGP-LS sessions when carrying SR information."  The Security Considerations in rfc8404 really only talk about the data plane -- I don't see how they apply to the BGP-LS sessions.

[major] "...precaution is necessary to ensure that the SR information collected via BGP-LS is limited to specific controllers or applications..."  This sounds as if you're referring to information that (once collected) can be shared between controllers -- I think that case is out of scope.  If you are trying to talk about the BGP sessions, then I think the language needs a little more work.  BTW, the paragraph below also talks about BGP sessions; suggestion: keep the common topics together.

[major] The end of the last sentence says "...in a secure manner within this SR domain".  Assuming that we're talking about BGP sessions, what does that mean?  Does it mean anything beyond what BGP is normally specified to do?  If not, then I would recommend taking that piece of text out to not invite more questions than needed.

[minor] You talk about "controllers or applications", but in the rest of the document you have mostly used "consumer" (which is a good thing because it shows consistency with rfc8402).  Suggestion: use "consumers" here as well.

1029   The isolation of BGP-LS peering sessions is also required to ensure
1030   that BGP-LS topology information (including the newly added SR
1031   information) is not advertised to an external BGP peering session
1032   outside an administrative domain.

[major] What does "isolation of BGP-LS peering sessions" mean?  Why is it not Normatively REQUIRED?

[major] From prior experience (see draft-ietf-idr-te-pm-bgp), the SecDir/Sec ADs asked for text related to why it is ok to transport the new information in BGP.  This is the text that resulted from that discussion:

  The TLVs introduced in this document are used to propagate IGP
  defined information ([I-D.ietf-lsr-isis-rfc7810bis] and [RFC7471].)
  These TLVs represent the state and resource availability of the IGP
  link.  The IGP instances originating these TLVs are assumed to
  support all the required security and authentication mechanisms (as
  described in [I-D.ietf-lsr-isis-rfc7810bis] and [RFC7471]) in order
  to prevent any security issue when propagating the TLVs into BGP-LS.
  The advertisement of the link attribute information defined in this
  document presents no additional risk beyond that associated with the
  existing set of link attribute information already supported in
  [RFC7752].

Note that this text is complementary to what is already stated in the first paragraph -- but goes into a more explicit explanation and brings in the security considerations from the documents where the IGP extensions are defined.  Consider adding something similar here.


...
1126 9.2.  Informative References
...
1159   [RFC8402]  Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
1160               Decraene, B., Litkowski, S., and R. Shakir, "Segment
1161               Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
1162               July 2018, .

[major] I think this should be a Normative reference.


1164 9.3.  URIs

[major] As mentioned before, please use References (above) instead of URIs.


...
1197   [12] http://tools.ietf.org/html/draft-ietf-isis-l2bundles-07

[major] The reference should become Normative (see §2.2.3).

Shepherd Write-up: per RFC 4858, template: 2/24/2012
last updated 2/11/2019.
--------------
(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 RFC - additions to RFC7752 (BGP-LS) in the
BGP-LS NLRI in order to pass segment routing (SR) information
for IGPS in the BGP-LS NLRI.  Extension to RFC7752 to add this
information includes:
a) Node NLRI within the BGP-LS NLRI that passes 
SR identifiers (SID), SR capabilities, SR algorithm, SR local
block range, and SR mapping server preference.
b) The Link NLRI within BGP-LS NLRI  that passes
SIDs for adjacency, LAN  adjaency SID, L2 Bundle TLV.
c) prefix NLRI within BGP-LS NLRI that passes:
Prefix SID, Prefix attribute (OSPFv2, OSPFv3, ISISflags),
Range of prefixes.

(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
  Segment Routing (SR) allows for a flexible definition of end-to-end
  paths by encoding paths as sequences of topological sub-paths, called
  "segments".  These segments are advertised by routing protocols e.g.
  by the link state routing protocols (IS-IS, OSPFv2 and OSPFv3) within
  IGP topologies.

  This draft defines extensions to the BGP Link-state address-family
  defined in RFC7752 in order to carry segment routing information
  for IGPs in BGP.  Extensions include additions to SR routing
  identifiers (SIDs) for IGP nodes, link adjacencies, and prefixes
  as well as passing information on SR capabilities,  algorithms and
  mapping servers.


Working Group Summary

The WG has reviewed the BGP-LS segment
routing drafts for 3-5 years in coordination with the
SPRING, MPLS, and BESS working groups.
Please read the RFC 8402 and
draft-ietf-spring-segement-routing-central-epe-15 to
understand the architecture construct. 

This draft is one of a family of BGP additions for BGP-LS
segment routing (SR) and and BGP Traffic
Engineering (TE) that IDR is standardizing after receiving
reports of 2 independent implementations.
Other drafts for segment routing reading for standardization
include: draft-ietf-idr-bgp-prefix-sid and
draft-ietf-idr-bgp-ls-segment-routing-ext.
Other drafts for BGP-LS based TE include: 
draft-ietf-idr-bgp-ls-node-admin-tag-extension and
draft-ietf-idr-te-pm-bgp-10.

Document Quality

1) technical quality:
Existing implementations of the protocol: 2 from Cisco
https://trac.ietf.org/trac/idr/wiki/draft-ietf-idr-bgp-ls-segment-routing-ext-implementations
Plans: Huawei has indicated plans to implement.

Careful reviews:
Jeff Haas (via comments on list) - resulted in -06
https://www.ietf.org/mail-archive/web/idr/current/msg19251.html
John Scudder's  follow-up
https://www.ietf.org/mail-archive/web/idr/current/msg19219.html

Aijun Wang
https://www.ietf.org/mail-archive/web/idr/current/msg19251.html
(Note: Aijun Wang is part of the operational community
as operator of a network in China).

WGLC:
https://www.ietf.org/mail-archive/web/idr/current/msg19116.html

RTG-DIR QA reviewer: Victoria Pritchard (pritchardv0@gmail.com)
https://mailarchive.ietf.org/arch/msg/rtg-dir/WmMfeAGp6C0j3WRf4NISO9nQOP0\

OPS-DIR QA Reviewer: Joel Jaeggli
https://datatracker.ietf.org/doc/review-ietf-idr-bgp-ls-segment-routing-ext-06-opsdir-early-jaeggli-2018-05-08/

Shepherd's comments on RTG-DIR QA review responses:
https://mailarchive.ietf.org/arch/msg/idr/mVc8RYCSXCbjWFa9kQOJ58Kd6tI

Shepherd's additional comments on security:
see thread:
https://www.ietf.org/mail-archive/web/idr/current/msg19987.html

OPS Comments from Grow  WG- sent to grow WG, but no comments received.
AD is welcome to ping WG chairs again.

Summary for IESG of the security thread:
The inclusion of the reference in the security consideration
in -10.txt of a specific reference to RFC8402 (SR architecture)
and a clear statement that these BGP-LS extensions
are to be operated in a trusted domain with
isolated BGP peers with filtering restrictions
so that this information cannot go outside this peers.
In this shepherd's understandings, these restrictions form
a web of trusted BGP peers. 

If these BGP peers operate in the SR-MPLS environment,
the authors believe the security analysis provided  by RFC4381 should apply. 
The shepherd is concerned regarding this statement, but if the
deployment is within a web of trusted BGP peers
then it is the web of trusted BGP peers (each validated
by configuration and other means) to the web.

These security restrictions are in addition to the
RFC7752  security restrictions.  Since RFC7752 does not provide require
a trusted domain or BGP-LS isolation these additional restrictions are important.

Personnel
  Document Shepherd: Susan Hares
  Responsible AD:  Alvaro Retana
  RTG-DIR QA reviewer: Victoria Pritchard (pritchardv0@gmail.com)
  OPS-DIR: QA reviewer: Joel Jaeggli
  Key onlist reviewers: Jeff Haas, Aijun Wang
 

(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.

Reviewer went through draft aligning it with other Spring and IDR work.
Reviwer went through the following key reviews:
1) WG LC - Jeff Haas, Aijun Wang
2) Requested QA Reviews

  RTG-DIR reviewer: Victoria Pritchard (pritchardv0@gmail.com)
https://mailarchive.ietf.org/arch/msg/rtg-dir/WmMfeAGp6C0j3WRf4NISO9nQOP0

  RTG-DIR QA reviewer: 
https://mailarchive.ietf.org/arch/msg/rtg-dir/WmMfeAGp6C0j3WRf4NISO9nQOP0

3) Requested Grow WG to review these two drafts for operational usefulness

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

No. 

No nits.

(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 additional review.

(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.

Robert Raszuk (and Tony Li's agreement) WG LC is worth reviewing here:
(see https://www.ietf.org/mail-archive/web/idr/current/msg19124.html)

Robert Rasuk and Tony Li feel that BGP-LS (RFC7752) was unwise direction for
BGP, and expanding it is a greater error.  The BGP-LS proponents suggested
that BGP-LS was simply a way to get IGP data (OSPFv2/v3, ISIS) out of a
network for processing. 

These segment routing additions take the BGP-LS
work beyond its initial description of providing information to
manage network into the realm of supporting  a centralized SDN controller which creates
Segment Routing infrastructure.

The IESG should consider whether this general application of
BGP-LS into creating routing infrastructure is important.
If it is, approve this document for publication and the
WG chairs and AD will note this decision point.

If it is not, then reject this document for publication with the
a clear statement that this expansion of work is not appropriate.

(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.

Stefano Previdi
https://www.ietf.org/mail-archive/web/idr/current/msg18493.html
https://www.ietf.org/mail-archive/web/idr/current/msg19229.html
https://mailarchive.ietf.org/arch/msg/idr/ei5hc-2kVeWscuSsdvnRx9g4pUI

Ketan Talaulikar
https://www.ietf.org/mail-archive/web/idr/current/msg19225.html

Clarence Filsfils
https://www.ietf.org/mail-archive/web/idr/current/msg18497.html
https://mailarchive.ietf.org/arch/msg/idr/WD1d9B0ZJRZx3HQ3pji3BTyQUxo

Hannes Gredler
https://www.ietf.org/mail-archive/web/idr/current/msg18498.html
https://www.ietf.org/mail-archive/web/idr/current/msg19231.html
https://mailarchive.ietf.org/arch/msg/idr/b5nsKpRyh4I5SvDKlGRnKABnSqo


Mach Chen
https://www.ietf.org/mail-archive/web/idr/current/msg18501.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 Disclosure

(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? 

WG in this area tends to be strong pushing toward the draft, but
there are concerns raised by the Robert Raszuk, Tony LI, and others
regarding this use of BGP as a transport for information.

(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 threats of an appeal.

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

No nits

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

(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?

Non-RFC normative
draft-ietf-idr-te-pm-bgp 0- approved for RFC
draft-ietf-isis-segment-routing-extensions - approved for publication
draft-ietf-ospf-ospfv3-segment-routing-extensions-15.txt = approved for publication

(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.
te the aut
-Not as I understand RFC3967

(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. These are additions to RFC7752. 

(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).

AFAIK - this draft followed early allocation procedures correctly.
I have sent a request for a IANA QA review, and
received an "OK" from IANA.
Please do a re-check of the last version.

(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.

None needed

Shepherd Write-up: per RFC 4858, template: 2/24/2012
last updated 2/11/2019.
--------------
(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 RFC - additions to RFC7752 (BGP-LS) in the
BGP-LS NLRI in order to pass segment routing (SR) information
for IGPS in the BGP-LS NLRI.  Extension to RFC7752 to add this
information includes:
a) Node NLRI within the BGP-LS NLRI that passes 
SR identifiers (SID), SR capabilities, SR algorithm, SR local
block range, and SR mapping server preference.
b) The Link NLRI within BGP-LS NLRI  that passes
SIDs for adjacency, LAN  adjaency SID, L2 Bundle TLV.
c) prefix NLRI within BGP-LS NLRI that passes:
Prefix SID, Prefix attribute (OSPFv2, OSPFv3, ISISflags),
Range of prefixes.

(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
  Segment Routing (SR) allows for a flexible definition of end-to-end
  paths by encoding paths as sequences of topological sub-paths, called
  "segments".  These segments are advertised by routing protocols e.g.
  by the link state routing protocols (IS-IS, OSPFv2 and OSPFv3) within
  IGP topologies.

  This draft defines extensions to the BGP Link-state address-family
  defined in RFC7752 in order to carry segment routing information
  for IGPs in BGP.  Extensions include additions to SR routing
  identifiers (SIDs) for IGP nodes, link adjacencies, and prefixes
  as well as passing information on SR capabilities,  algorithms and
  mapping servers.


Working Group Summary

The WG has reviewed the BGP-LS segment
routing drafts for 3-5 years in coordination with the
SPRING, MPLS, and BESS working groups.
Please read the draft-ietf-spring-segment-routing and
draft-ietf-spring-segement-routing-central-epe-15 to
understand the architecture construct. 

This draft is one of a family of BGP additions for BGP-LS
segment routing (SR) and and BGP Traffic
Engineering (TE) that IDR is standardizing after receiving
reports of 2 independent implementations.
Other drafts for segment routing reading for standardization
include: draft-ietf-idr-bgp-prefix-sid and
draft-ietf-idr-bgp-ls-segment-routing-ext.
Other drafts for BGP-LS based TE include: 
draft-ietf-idr-bgp-ls-node-admin-tag-extension and
draft-ietf-idr-te-pm-bgp-10.

Document Quality

1) technical quality:
Existing implementations of the protocol: 2 from Cisco
https://trac.ietf.org/trac/idr/wiki/draft-ietf-idr-bgp-ls-segment-routing-ext-implementations
Plans: Huawei has indicated plans to implement.

Careful reviews:
Jeff Haas (via comments on list) - resulted in -06
https://www.ietf.org/mail-archive/web/idr/current/msg19251.html
John Scudder's  follow-up
https://www.ietf.org/mail-archive/web/idr/current/msg19219.html

Aijun Wang
https://www.ietf.org/mail-archive/web/idr/current/msg19251.html

(Note: Aijun Wang is employed by:
Network R&D and Operation Support Department
China Telecom Corporation Limited Beijing Research Institute,Beijing, China.)

WGLC:
https://www.ietf.org/mail-archive/web/idr/current/msg19116.html

RTG-DIR QA reviewer: Victoria Pritchard (pritchardv0@gmail.com)
https://mailarchive.ietf.org/arch/msg/rtg-dir/WmMfeAGp6C0j3WRf4NISO9nQOP0\

OPS-DIR QA Reviewer: Joel Jaeggli
https://datatracker.ietf.org/doc/review-ietf-idr-bgp-ls-segment-routing-ext-06-opsdir-early-jaeggli-2018-05-08/

Shepherd's comments on RTG-DIR QA review responses:
https://mailarchive.ietf.org/arch/msg/idr/mVc8RYCSXCbjWFa9kQOJ58Kd6tI

Shepherd's additional comments on security:
see thread:
https://www.ietf.org/mail-archive/web/idr/current/msg19987.html

OPS Comments from Grow  WG- sent to grow WG, but no comments received.
AD is welcome to ping WG chairs again.

Summary for IESG of the security thread:
The inclusion of the reference in the security consideration
in -10.txt of a specific reference to RFC8402 (SR architecture)
and a clear statement that these BGP-LS extensions
are to be operated in a trusted domain with
isolated BGP peers with filtering restrictions
so that this information  cannot go outside this peers.
In my understandings, these restrictions form
a web of trusted BGP peers. 
If these BGP peers operate in the SR-MPLS
environment, the security analysis provided
by RFC4381 should apply. 

These security restrictions are in addition to the
RFC7752  security restrictions.
Since RFC7752 does not provide require
a trusted domain or BGP-LS isolation these
additional restrictions are important.

Personnel
  Document Shepherd: Susan Hares
  Responsible AD:  Alvaro Retana
  RTG-DIR QA reviewer: Victoria Pritchard (pritchardv0@gmail.com)
  OPS-DIR: QA reviewer: Joel Jaeggli
  Key onlist reviewers: Jeff Haas, Aijun Wang
 

(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.

Reviewer went through draft aligning it with other Spring and IDR work.
Reviwer went through the following key reviews:
1) WG LC - Jeff Haas, Aijun Wang
2) Requested QA Reviews

  RTG-DIR reviewer: Victoria Pritchard (pritchardv0@gmail.com)
https://mailarchive.ietf.org/arch/msg/rtg-dir/WmMfeAGp6C0j3WRf4NISO9nQOP0

  RTG-DIR QA reviewer: 
https://mailarchive.ietf.org/arch/msg/rtg-dir/WmMfeAGp6C0j3WRf4NISO9nQOP0

3) Requested Grow WG to review these two drafts for operational usefulness

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

No. 

No nits.

(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 additional review.

(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.

Robert Raszuk (and Tony Li's agreement) WG LC is worth reviewing here:
(see https://www.ietf.org/mail-archive/web/idr/current/msg19124.html)

Robert Rasuk and Tony Li feel that BGP-LS (RFC7752) was unwise direction for
BGP, and expanding it is a greater error.  The BGP-LS proponents suggested
that BGP-LS was simply a way to get IGP data (OSPFv2/v3, ISIS) out of a
network for processing.  The segment routing additions take the BGP-LS
work into supporting a centralized SDN controller which creates
Segment Routing.  The IESG should consider whether this is appropriate.


(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.

Stefano Previdi
https://www.ietf.org/mail-archive/web/idr/current/msg18493.html
https://www.ietf.org/mail-archive/web/idr/current/msg19229.html
https://mailarchive.ietf.org/arch/msg/idr/ei5hc-2kVeWscuSsdvnRx9g4pUI

Ketan Talaulikar
https://www.ietf.org/mail-archive/web/idr/current/msg19225.html

Clarence Filsfils
https://www.ietf.org/mail-archive/web/idr/current/msg18497.html
https://mailarchive.ietf.org/arch/msg/idr/WD1d9B0ZJRZx3HQ3pji3BTyQUxo

Hannes Gredler
https://www.ietf.org/mail-archive/web/idr/current/msg18498.html
https://www.ietf.org/mail-archive/web/idr/current/msg19231.html
https://mailarchive.ietf.org/arch/msg/idr/b5nsKpRyh4I5SvDKlGRnKABnSqo


Mach Chen
https://www.ietf.org/mail-archive/web/idr/current/msg18501.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 Disclosure

(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? 

WG in this area tends to be strong pushing toward the draft, but
there are concerns raised by the Robert Raszuk, Tony LI, and others
regarding this use of BGP as a transport for information.

(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 threats of an appeal.

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

No nits

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

(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?

Non-RFC normative
draft-ietf-idr-te-pm-bgp
- passed WG LC, this shepherd forward to IESG, see note below.
draft-ietf-isis-segment-routing-extensions
-pased WG LC, awaiting shepherd's write-up
draft-ietf-ospf-ospfv3-segment-routing-extensions-15.txt
- passed WG LC, AD review asked for a revised ID.

draft-ietf-idr-te-pm-bgp  has been forwarded to the
IESG, but the sec-dir early review found problems.
See this discussion:
https://www.ietf.org/mail-archive/web/idr/current/msg19953.html

Explanation for the IESG on draft-ietf-idr-te-pm-bgp
The shepherd disagreed with the authors on the quality of the
security consideration's section in draft-ietf-idr-te-pm-bgp.
One of the authors (Les Ginsberg) felt the  shepherd/WG chair
suggest to revise the security consideration secion was
unreasonable.  The resolution was to have an independent secdir review of this
draft that focused specifically on the security considerations.
Security directorate found the same concerns the shepherd did that the
security considerations in RFC5572 are vague and do not
provide sufficient protection for this additional TE information.
Please see the shepherd review for that draft for further details.

(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.

-Not as I understand RFC3967

(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. These are additions to RFC5572.

(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).

AFAIK - this draft followed early allocation procedures correctly.
I have sent a request for a IANA QA review, and
received an "OK" from IANA.
Please do a re-check of the last version.

(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.

None needed

Shepherd Write-up: per RFC 4858, template: 2/24/2012
Action items:
1) Sent to the Routing AD for publication
2) Resent  to Grow WG (11/4/2018) to get early feedback on ops-dir -
--------------
(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 RFC - additions to RFC7752 (BGP-LS) in the
BGP-LS NLRI in order to pass segment routing (SR) information
for IGPS in the BGP-LS NLRI.  Extension to RFC7752 to add this
information includes:
a) Node NLRI within the BGP-LS NLRI that passes 
SR identifiers (SID), SR capabilities, SR algorithm, SR local
block range, and SR mapping server preference.
b) The Link NLRI within BGP-LS NLRI  that passes
SIDs for adjacency, LAN  adjaency SID, L2 Bundle TLV.
c) prefix NLRI within BGP-LS NLRI that passes:
Prefix SID, Prefix attribute (OSPFv2, OSPFv3, ISISflags),
Range of prefixes.

(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
  Segment Routing (SR) allows for a flexible definition of end-to-end
  paths by encoding paths as sequences of topological sub-paths, called
  "segments".  These segments are advertised by routing protocols e.g.
  by the link state routing protocols (IS-IS, OSPFv2 and OSPFv3) within
  IGP topologies.

  This draft defines extensions to the BGP Link-state address-family
  defined in RFC7752 in order to carry segment routing information
  for IGPs in BGP.  Extensions include additions to SR routing
  identifiers (SIDs) for IGP nodes, link adjacencies, and prefixes
  as well as passing information on SR capabilities,  algorithms and
  mapping servers.


Working Group Summary

The WG has reviewed the BGP-LS segment
routing drafts for 3-5 years in coordination with the
SPRING, MPLS, and BESS working groups.
Please read the draft-ietf-spring-segment-routing and
draft-ietf-spring-segement-routing-central-epe-15 to
understand the architecture construct. 

This draft is one of a family of BGP additions for BGP-LS
segment routing (SR) and and BGP Traffic
Engineering (TE) that IDR is standardizing after receiving
reports of 2 independent implementations.
Other drafts for segment routing reading for standardization
include: draft-ietf-idr-bgp-prefix-sid and
draft-ietf-idr-bgp-ls-segment-routing-ext.
Other drafts for BGP-LS based TE include: 
draft-ietf-idr-bgp-ls-node-admin-tag-extension and
draft-ietf-idr-te-pm-bgp-10.

Document Quality

1) technical quality:
Existing implementations of the protocol: 2 from Cisco
https://trac.ietf.org/trac/idr/wiki/draft-ietf-idr-bgp-ls-segment-routing-ext-implementations
Plans: Huawei has indicated plans to implement.

Careful reviews:
Jeff Haas (via comments on list) - resulted in -06
https://www.ietf.org/mail-archive/web/idr/current/msg19251.html
John Scudder's  follow-up
https://www.ietf.org/mail-archive/web/idr/current/msg19219.html

Aijun Wang
https://www.ietf.org/mail-archive/web/idr/current/msg19251.html

(Note: Aijun Wang is employed by:
Network R&D and Operation Support Department
China Telecom Corporation Limited Beijing Research Institute,Beijing, China.)

WGLC:
https://www.ietf.org/mail-archive/web/idr/current/msg19116.html

RTG-DIR QA reviewer: Victoria Pritchard (pritchardv0@gmail.com)
https://mailarchive.ietf.org/arch/msg/rtg-dir/WmMfeAGp6C0j3WRf4NISO9nQOP0\

OPS-DIR QA Reviewer: Joel Jaeggli
https://datatracker.ietf.org/doc/review-ietf-idr-bgp-ls-segment-routing-ext-06-opsdir-early-jaeggli-2018-05-08/

Shepherd's comments on RTG-DIR QA review responses:
https://mailarchive.ietf.org/arch/msg/idr/mVc8RYCSXCbjWFa9kQOJ58Kd6tI

Shepherd's additional comments on security:
see thread:
https://www.ietf.org/mail-archive/web/idr/current/msg19987.html

Summary for IESG of the security thread:
The inclusion of the reference in the security consideration
in -10.txt of a specific reference to RFC8402 (SR architecture)
and a clear statement that these BGP-LS extensions
are to be operated in a trusted domain with
isolated BGP peers with filtering restrictions
so that this information  cannot go outside this peers.
In my understandings, these restrictions form
a web of trusted BGP peers. 
If these BGP peers operate in the SR-MPLS
environment, the security analysis provided
by RFC4381 should apply. 

These security restrictions are in addition to the
RFC7752  security restrictions.
Since RFC7752 does not provide require
a trusted domain or BGP-LS isolation these
additional restrictions are important.

Personnel
  Document Shepherd: Susan Hares
  Responsible AD:  Alvaro Retana
  RTG-DIR QA reviewer: Victoria Pritchard (pritchardv0@gmail.com)
  OPS-DIR: QA reviewer: Joel Jaeggli
  Key onlist reviewers: Jeff Haas, Aijun Wang
 

(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.

Reviewer went through draft aligning it with other Spring and IDR work.
Reviwer went through the following key reviews:
1) WG LC - Jeff Haas, Aijun Wang
2) Requested QA Reviews

  RTG-DIR reviewer: Victoria Pritchard (pritchardv0@gmail.com)
https://mailarchive.ietf.org/arch/msg/rtg-dir/WmMfeAGp6C0j3WRf4NISO9nQOP0

  RTG-DIR QA reviewer: 
https://mailarchive.ietf.org/arch/msg/rtg-dir/WmMfeAGp6C0j3WRf4NISO9nQOP0

3) Requested Grow WG to review these two drafts for operational usefulness

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

No. 

No nits.

(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 additional review.

(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.

Robert Raszuk (and Tony Li's agreement) WG LC is worth reviewing here:
(see https://www.ietf.org/mail-archive/web/idr/current/msg19124.html)

Robert Rasuk and Tony Li feel that BGP-LS (RFC7752) was unwise direction for
BGP, and expanding it is a greater error.  The BGP-LS proponents suggested
that BGP-LS was simply a way to get IGP data (OSPFv2/v3, ISIS) out of a
network for processing.  The segment routing additions take the BGP-LS
work into supporting a centralized SDN controller which creates
Segment Routing.  The IESG should consider whether this is appropriate.


(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.

Stefano Previdi
https://www.ietf.org/mail-archive/web/idr/current/msg18493.html
https://www.ietf.org/mail-archive/web/idr/current/msg19229.html
https://mailarchive.ietf.org/arch/msg/idr/ei5hc-2kVeWscuSsdvnRx9g4pUI

Ketan Talaulikar
https://www.ietf.org/mail-archive/web/idr/current/msg19225.html

Clarence Filsfils
https://www.ietf.org/mail-archive/web/idr/current/msg18497.html
https://mailarchive.ietf.org/arch/msg/idr/WD1d9B0ZJRZx3HQ3pji3BTyQUxo

Hannes Gredler
https://www.ietf.org/mail-archive/web/idr/current/msg18498.html
https://www.ietf.org/mail-archive/web/idr/current/msg19231.html
https://mailarchive.ietf.org/arch/msg/idr/b5nsKpRyh4I5SvDKlGRnKABnSqo


Mach Chen
https://www.ietf.org/mail-archive/web/idr/current/msg18501.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 Disclosure

(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? 

WG in this area tends to be strong pushing toward the draft, but
there are concerns raised by the Robert Raszuk, Tony LI, and others
regarding this use of BGP as a transport for information.

(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 threats of an appeal.

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

No nits

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

(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?

Non-RFC normative
draft-ietf-idr-te-pm-bgp
- passed WG LC, this shepherd forward to IESG, see note below.
draft-ietf-isis-segment-routing-extensions
-pased WG LC, awaiting shepherd's write-up
draft-ietf-ospf-ospfv3-segment-routing-extensions-15.txt
- passed WG LC, AD review asked for a revised ID.

draft-ietf-idr-te-pm-bgp  has been forwarded to the
IESG, but the sec-dir early review found problems.
See this discussion:
https://www.ietf.org/mail-archive/web/idr/current/msg19953.html

Explanation for the IESG on draft-ietf-idr-te-pm-bgp
The shepherd disagreed with the authors on the quality of the
security consideration's section in draft-ietf-idr-te-pm-bgp.
One of the authors (Les Ginsberg) felt the  shepherd/WG chair
suggest to revise the security consideration secion was
unreasonable.  The resolution was to have an independent secdir review of this
draft that focused specifically on the security considerations.
Security directorate found the same concerns the shepherd did that the
security considerations in RFC5572 are vague and do not
provide sufficient protection for this additional TE information.
Please see the shepherd review for that draft for further details.

(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.

-Not as I understand RFC3967

(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. These are additions to RFC5572.

(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).

AFAIK - this draft followed early allocation procedures correctly.
I have sent a request for a IANA QA review, and
received an "OK" from IANA.
Please do a re-check of the last version.

(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.

None needed

From: "John G. Scudder"
Subject: Re: draft-ietf-idr-bgp-ls-segment-routing-ext prior to WG LC (7/17 - 7/31)
Date: October 19, 2017 at 3:59:26 PM GMT+3
To: "idr@ietf. org"
Cc: "Dongjie (Jimmy)" , Susan Hares

Hi All,

I see that we never formally closed this WGLC.

Since there were no replies at all to the WGLC, there is no consensus to advance the document. Presumably there is still interest in it, considering we were asked for -- and provided -- early allocations, subsequent to the WGLC. So, I guess the WG should reconsider the WGLC in the future, after we've processed the other outstanding WGLCs in our queue.

--John

Request for posting confirmation emailed to previous authors: Stefano Previdi , Hannes Gredler , idr-chairs@ietf.org, Peter Psenak , " jefftant@gmail.com" , Mach Chen , Clarence Filsfils

Request for posting confirmation emailed to previous authors: "Mach Chen" , idr-chairs@ietf.org, "Hannes Gredler" , "Clarence Filsfils" , "Stefano Previdi" , " jefftant@gmail.com" , "Peter Psenak"