YANG Data Model for Traffic Engineering (TE) Topologies
draft-ietf-teas-yang-te-topo-22

Note: This ballot was opened for revision 15 and is now closed.

Deborah Brungard Yes

(Ignas Bagdonas) No Objection

Comment (2018-06-07 for -16)
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Focusing on YANG modules part only (as ran out of time for detailed review of reasoning behind model design) there does not appear to be any noticeable problems.

(Ben Campbell) No Objection

Comment (2018-06-06 for -16)
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Just some editorial comments:

- There is conflicting 2119/8174 boilerplate in the front material and in §1.1. I assume the latter is the correct boilerplate.

- The writing style makes heavy use of imbedded definitions and examples in parenthetical phrases. I personally find that creates quite a bit of readability friction. It would be easier to read if such things were split out into their own sentences.

- Some of the figures have legends, but most do not. It would be very helpful to include legends in those figures that depend on different line styles to convey meaning. (e.g. Figure 1).

Alissa Cooper No Objection

(Spencer Dawkins) No Objection

Comment (2018-06-05 for -16)
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I found myself wondering what the last sentence in 

  - TE Topology may not be congruent to the routing topology (topology
     constructed based on routing adjacencies) in a given TE System.
     There isn't always a one-to-one association between a TE-link and
     a routing adjacency. For example, the presence of a TE link
     between a pair of nodes doesn't necessarily imply the existence of
     a routing-adjacency between these nodes.

was saying about what IS implied between these nodes. I'm guessing, but this draft seems to assume a relatively low level amount of experience with traffic engineering, so I can imagine readers who could benefit from a word or two of explanation.

Benjamin Kaduk No Objection

Comment (2018-06-06 for -16)
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Thanks to Alvaro for pointing out the specific considerations on the geolocation variables.

This document has a large number (6) of authors; https://www.rfc-editor.org/policy.html#policy.authlist
implies that justification is needed for more than 5 authors.

Section 3.4

I'm confused why the transitional TE link disappears once a normal
TE link abstracting away the layer transition appears -- is there no
longer potential to do layer transition at that node (e.g., to take
a different path in the server layer network) once a layer
transition is in use?

Section 8

I'm not sure I understand why the te:templates tree is not called
out as "sensitive" -- is it just the "template" nature?  Lots of
these look like things that could have detrimental impact if
modified in an actual live instance -- ID, bandwidth, type, etc., so
I mostly assume that it's just the templatey-ness, but don't quite
understand how that works.


There are a number of places where editorial attention would be beneficial; I only noted a
small subset of them.  One recurring theme is "<foo> is assigned with the <bar>  unique ID", which
might be more clearly phrased as "A <foo> is assigned a unique ID within the scope of <bar>".  Some
other specific items follow.

Section 1

   [...] There could be one or more TE Topologies present in a given
   Traffic Engineered system. The TE Topology is the topology on which
   path computational algorithms are run to compute Traffic Engineered
   Paths (TE Paths).

nit: If there could be more than one, it seems grammatically
improper to use the definite article "the" (without further
qualification) to refer to them.

Section 1.1

   Customized TE Topology: Customized TE Topology is a custom topology
   that is produced by a provider for a given Client. This topology
   typically augments the Client's Native TE Topology. Path
   computational algorithms aren't typically run on the Customized TE
   Topology; they are run on the Client's augmented Native TE Topology.

This text doesn't really help me tell the difference between the
"Client's augmented Native TE Topology" and the "Customized TE
Topology", which is the Client's Native TE Topology plus some
unspecified augmentation (that is apparently different from the one
used for path computation).

Section 2

   - Each TE Topological element has an information source associated
     with it. In some scenarios, there could be more than one
     information source associated with each topological element.

editorial: I'd suggest replacing the last "each" with "any given",
and maybe "has an" with "has at least one".

Section 3.3

   TE link is an element of a TE topology (presented as an edge on TE
   graph, arrows indicate one or both directions of the TE link).

(I don't see any arrows in Figure 1.)

   [...] TE link
   is connected to TE node, terminating the TE link via exactly one TE
   link termination point (LTP).

Even unidirectional links have a source and destination; presumably
both of those are attributes of the TE link?  Perhaps "for any given
node" should be more explicit?

Section 3.8

   [...] From the point of view of
   a potential TE path LLCL provides a list of valid TE links the TE
   path needs to start/stop on for the connection, taking the TE path,
   to be successfully terminated on the TTP in question.

nit: this could probably be reworded to be more clear, maybe:

%  From the point of view of usability in creating a TE path, the LLCL
%  provides a list of the TE links that would be valid path components
%  for paths involving the TTP in question.

Section 3.10

   is unique across all TE topologies provided by the same provider.  The
   client layer LIPs and the server layer TTPs associated within a given

Should that be "LTPs" instead of "LIPs"?

Section 4.4

   [...] maintain. For example, in addition to the merged TE topology depicted
   in the upper part of Figure 1, the client may merge the abstract TE

Figure 1 was long ago and does not seem relevant.  Was this supposed
to be Figure 9 or Figure 10?

Section 7

     grouping connectivity-label-restriction-list {
       description
         "List of abel restrictions specifying what labels may or may
          not be used on a link connectivity.";
       list label-restriction {
         key "index";
         description
           "List of abel restrictions specifying what labels may or may
            not be used on a link connectivity.";

presumably "label" rather than "abel" (twice)?

Another typo -- "speficied" for "specified" (also twice).
And "souruce" for "source" (twice)

Appendix C

Are there really supposed to be 63 occurrences of the string
"Attribute 11 for example technology" (i.e., with no "Attribute 1",
"Attribute 2", etc.)?

(Suresh Krishnan) No Objection

Warren Kumari No Objection

Comment (2018-06-06 for -16)
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In the “Trusting AD, ran out of time “ sense.

(Mirja Kühlewind) No Objection

(Terry Manderson) No Objection

(Alexey Melnikov) No Objection

Alvaro Retana No Objection

Comment (2018-06-06 for -16)
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Security Considerations: It is important to call out the fact that the sensitive information in the readable data nodes includes geolocation.

(Adam Roach) No Objection

Comment (2018-06-06 for -16)
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I agree with Warren's comment. ;-)