RIFT: Routing in Fat Trees
draft-ietf-rift-rift-24

Received changes through RFC Editor sync (changed state to RFC, created became rfc relationship between draft-ietf-rift-rift and RFC 9692, changed IESG state to RFC Published)

[Ballot comment]
(ballot revised to cover -23, and the again on -24)

Thank you to Robert Sparks for the early GENART review.

Thanks for address some of my COMMENT and DISCUSS points.

[Ballot discuss]
** [-23] Section 6.9.3.
  Any value in
  the packet following a security fingerprint MUST be used by a
  receiver only after the appropriate fingerprint has been validated
  against the data covered by it and the advertised key bare exceptions
  arising from operational exigencies where, based on local
  configuration, a node MAY allow for the envelope's integrity checks
  to be skipped and behavior specified in Section 6.9.6.

Thanks for introducing this revised text based on by -22 ballot.  If fingerprints can be 0 or not checked at all, doesn’t this open RIFT deployments to a “stripping attack”?  That is, an on-path adversary can simply remove the signature.  Would the end-point know that it should expect this outer fingerprint due to configuration?

Your response to my earlier COMMENT on this related matter suggested a number mitigating factors.  Please document them in the Security Considerations.

** [-22 and -23] Section 9.  The document contains no indication of an MTI algorithm to use to generate the fingerprint?  As consequence:
-- How are the security claims in this section able to be evaluated?

-- How is it possible to create an interoperable solution?

Can further guidance be provided?

[Response to -22 ballot]
> in at least my long experience with routing
> protocol security most attempts aimed at defining
> "use _this_ algorithm or _this_ family" ended up in a
> while as dangerous since one thing I can rely
> in security algorithms is so far that they
> are obsoleted/broken/going out of fashion at a
> much faster rate than routing protocols are deployed ;-)
>
> So, we chose conciously just to include key-ID
> and whatever algorithm/secrets are behind it is
> outside the scope of the doc as the most future safe solution.
>
> The document does NOT include any kind of specification
> for specific interoperable security based on some
> algorithm/secret but simply provides a
> framework any type of security can be plugged in.
...

> "A RIFT deployment that chooses to protect integrity
> of adjacencies and TIEs SHOULD deploy algorithm-XXX
> using key-ID YYYY as its default choice."

Thanks for this thoughtful response.  In my assessment, the lack of any MTI signature algorithm is both an interoperability and security issue that requires a resolution.  Without an MTI, one can’t be confident that two RIFT implementations will work with each other.  Since no algorithms are enumerated at all, there is no way to assess the stated security properties.

We’re of similar minds on hardcoding an algorithm into the protocol.  To the idea of algorithm agility, it seems like a similar problem has been considered by TLS [1], DNSSEC [2], SSH, IPsec, HTTP web signatures [3], etc. by creating an IANA registry of algorithm identifiers to choose, and if desired, an additional column associated with these identifiers noting if it is recommended by the IETF.  This allows the IETF to make recommendations on algorithms and to evolve these recommendations over time by changing the registry values.  If a sufficiently flexibility registration policy is established, it allows vendors to get code points for whatever additional algorithms they might want above and beyond what the IETF specified.

(A part of?) the Key ID would reference a value in this registry.  See related COMMENT below.  Is there a reason why RIFT couldn’t create a registry?

Implicit in this registry idea is a (set of) MTI algorithms.  I realize that this might be big change, so I won’t insist on this particular solution.  Based on my confusion in the COMMENTs about whether we are dealing with an HMAC or signature, I can’t make a recommendation.  I’d also like the SEC ADs to also weigh in on such recommendations.

[1] https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml#tls-parameters-4

[2] https://www.iana.org/assignments/dns-sec-alg-numbers/dns-sec-alg-numbers.xhtml#dns-sec-alg-numbers-1

[3] https://www.iana.org/assignments/http-message-signature/http-message-
signature.xhtml#signature-algorithms


** Section 10.2.* sets the registration policy for a number of registries as “Expert Review”.  What criteria should the expert be using?

[Response to -22 DISCUSS]
> Hmmm, new concept to me. AFAIR expert review
> just meant you assign bunch experts that
> are on the registry and when someone wants
> a new value they get pinged to discuss

Understood.  Is there no guidance to provide the expert reviewer on who they should evaluate the request?  See Section 5.3 of RFC8126: “When a designated expert is used, the documentation should give clear guidance to the designated expert, laying out criteria for performing an evaluation and reasons for rejecting a request.”

[Ballot comment]
(revised ballot covering -23)

Thank you to Robert Sparks for the early GENART review.

Thanks for address some of my earlier COMMENT and DISCUSS points

** Section 6.9.3.  Outer Key ID and TE Origin Key ID.  The description of both of these fields says “This implies key type and algorithm.”  What does that mean?

[Response to -22]
> as explained above. the key ID is just a pointer
> to something that has to
> be configured e'where consistently.
>
> so keyid=1 may mean, I run SHA-512 here with
> shared secret "NeverGuessed"

I appreciate concrete examples, but I’m confused by them.  Which cryptographic primitive is intended for use here?  I ask because I’m not sure how do you get “signature” from a SHA-512 and shared secret?  Typically, a hash algorithm+shared secret is a HMAC.

The text below seems to suggest PKI.  That’s historically been used in a signature algorithm.

HMAC and signatures have different properties.  The former doesn’t provide non-repudiation.  What are the security properties? 

Additionally, the text says “key type and algorithm” and the example is “SHA512 with secret key=NeverGuessed”.  To clarify, is the KeyID an algorithm and a particular associated key value?  I ask because I read “key type” as “plaintext string” or “PKCS12”, as in a format. 

That KeyID is an opaque identifier which points into a keystore that include an algorithm, key format, key value.

> or keyid=2000 may mean "here's my public
> signature you can verify on the
> TIE I issued" by a node.
>
> Pls suggest language to clarify otherwise

The above is also not clear to me. Is there some assumption that an implementation would have internal/configurable logic to know the location of the certificate associated with keyid=2000?

[Ballot comment]
[Updated position to No Objection]

# Gunter Van de Velde, RTG AD, comments for draft-ietf-rift-rift-21

Thanks to the authors for the epic amount of work put into this document.
Thanks to Loa Andersson, Jonathan Hardwick and Russ White for their valuable RTG DIR reviews
Thanks to Zheng Zhang for the shepherd writeup

The blocking DISCUSS items have been resolved from RTG AD perspective in v23 of the RIFT specification

Please find some some few non-blocking COMMENT points.

Please find https://www.ietf.org/blog/handling-iesg-ballot-positions/ documenting the handling of ballots.

#DISCUSS items (for reference only)
#==================================

359   First, it introduces RIFT's packet format content in the form of a
360   normative Thrift model given in Appendix B.3 carried in according

[RESOLVED DISCUSS#1] Normative statements are normally not added in Appendixes. 
Normative content, procedure rules that must be followed to conform
to the standard, is typically found in the main body of the document.

[RESOLVED DISCUSS#2] What is the difference between Distance and Cost used in the document?
These are both in the terminology section, however the difference is unclear (to me).
Both are used within the document extensive. Readers understanding of the
difference is paramount.

[RESOLVED DISCUSS#3] Section 6.2 talks about MTU. I have seen often issues between
neighbors due to (accidental) MTU mismatches. In addition the section
assumes that MTU (transmit) == MRU (receive). Beyond this it is
not specified if this is the L2 MTU or L3 MTU? Often the MTU
on the wire depends upon the L2/L3 encap used. The specifics should be nailed
down on what is intended as the MTU used for RIFT schema.

[RESOLVED DISCUSS#4] Section 6.7 about ZTP. Often the terminology ZTP is associated with
securely adding/booting nodes into a network and guarding none have been
tampered with. ZTP in section 6.7 however seems to describe ZTP from
the perspective of RIFT to allow a node to figure out its level, its
neighbors and its RIFT centric configuration. Unless somewhere else specified
a more explicit RIFT ZTP goals, non-goals and objectives will be help. In section 6.9
some of this is touched upon, however i found the role (current and potential
future extensions) of section 6.7 ZTP somewhat unclear from this perspective.

#GENERIC COMMENTS
#================
##The document is well written in both descriptive and normative style.
In general a wonderful achievement from the authors. i did wonder however
if certain sections can not be made less complicated and with less
wide scope to lower the threshold level for implementers to implement RIFT.

##The document is very long and is an intense complex read. I can
not claim i understand everything in super detail as that would take a
lot more time then available to digest/review this document.

##The security section 9 is a nice security overview of RIFT with loads of details

##The abstract appears to present a rationale for employing Clos or
fat pipe topologies in IP fabrics. However, I would argue that the primary intent
of RIFT is not to justify the use of these specific topologies but is aimed
to be a routing protocol specifically designed for these architectures.

The abstract should provide a glimpse into what RIFT is about. What about
this conceptual rewrite proposal:

    "The document details the Routing in Fat Trees (RIFT) protocol, specifically
    designed for use in Clos and fat-tree network topologies. It aims to reduce
    the complexity and state requirements of the control plane in these networks.
    RIFT addresses both the configuration and operational aspects, enhancing
    efficiency through specialized mechanisms."

##May i suggest add the following introduction summary overview into the introduction
section an overview of the key promised features from RIFT.

Key features of RIFT include:

Topology Awareness: RIFT is tailored for networks with a clear "top" and "bottom",
which is typical of Clos or fat-tree structures. This orientation allows for
optimized data flow management.

Dual Functionality: The protocol functions as a link-state protocol when
routing "north" and as a path-vector protocol when routing "south". This dual
approach helps in efficiently managing the routing information.

Flooding Mechanisms: RIFT employs selective flooding techniques to limit
the spread of routing information to necessary nodes only, thereby
reducing overhead.

Zero Touch Provisioning (ZTP): RIFT supports ZTP, which allows devices
to be configured automatically with minimal manual intervention, leveraging
the structured nature of fat-tree topologies.

Topology Exchange: Through Topology Information Elements (TIEs), RIFT handles
the dissemination of topology and routing information, facilitating both northbound
and southbound routing directions.

Failure Management: The protocol includes mechanisms for handling link
and node failures effectively, using concepts like automatic disaggregation
to maintain network stability and route availability.

Efficient Convergence: RIFT is designed to achieve fast convergence
across large and complex topologies, essential for maintaining high availability
and performance in data center environments.

##YANG data model vs KV store
The document includes a KV datastore, but makes no statement or indication about
YANG models/keys/lists. Seems as a missed opportunity

#DETAILED COMMENTS
#=================

classified as [minor] and [major]

359   First, it introduces RIFT's packet format content in the form of a
360   normative Thrift model given in Appendix B.3 carried in according

[minor] Thrift model: Thrift is a software framework for scalable cross-language
services development. Maybe the pointer to the reference should be used at
first occurrence. There is a reference, but its not added to the first
terminology occurrence but at a later moment.

406   Section 7 contains a set of comprehensive examples that show how RIFT
407   contains the impact of failures to only the required set of nodes.
408   It should also help cement some of RIFT's core concepts in the
409   reader's mind.

[minor] Should section 7 be better located in an informative appendix
to reduce the normative part of the RIFT procedures

411   Last, but not least, RIFT has other optional capabilities.  One
412   example is the key-value data-store, which enables RIFT to advertise
413   data post-convergence in order to bootstrap higher levels of
414   functionality (e.g. operational telemetry).  Those are covered in
415   Section 6.8.

[minor] KV store seems close aligned with how the yang model will look like.
However, the word yang only appears once for a different purpose. intentional?

452   Clos/Fat Tree:
453       This document uses the terms Clos and Fat Tree interchangeably
454       where it always refers to a folded spine-and-leaf topology with
455       possibly multiple Points of Delivery (PoDs) and one or multiple
456       Top of Fabric (ToF) planes.  Several modifications such as leaf-
457       2-leaf shortcuts and multiple level shortcuts are possible and
458       described further in the document.

[minor] It would be useful to at least introduce once what is exactly a fat
tree topology. This seems as a fine location for that purpose.
"A fat tree topology is a structured network design that is commonly
used in large-scale and high-performance computing environments, including
data centers. This topology is a variation of the tree topology, characterized by
increased bandwidth closer to the root of the tree where traffic
concentration is higher."

460   Cost:
461       The sum of metrics between two nodes.
...
479   Distance:
480       The sum of costs (bound by infinite distance) between two nodes.

[major] I have no idea what the difference between Cost and Distance is based
upon this description. Can this be explained better?

505   Leaf-to-Leaf Shortcuts (L2L):
506       East-West links at leaf level will need to be differentiated from
507       East-West links at other levels.

[minor] risk for Terminology confusion. A "shortcut" typically, especially used
with MPLS, refers to a technique used to optimize the path that data
takes through a network, potentially bypassing certain nodes or segments
to improve performance, reduce latency, or manage bandwidth more effectively.
The shortcut here seems something else? is shortcut the best term to
use for this?

847   the overhead of building an update per adjacency.  For the moment
848   describing the East-West direction is left out.

[minor] "left out" of the RIFT specification or out of the current section?

860   reachability information from multiple directions.  Its computation
861   principles (south forwarding direction is always preferred) leads to
862   valley-free [VFR] forwarding behavior.  And since valley free routing
863   is loop-free, it can use all feasible paths.  This is another highly

[minor] i was not familiar with the term Valley-Free routing.
I did some research and found that in valley-free routing, a route is considered
valid if it only traverses paths that go up the hierarchy (from a lower-tier level
to a higher-tier level) or horizontally (between levels of the same tier), and then
potentially down the hierarchy (from a higher-tier level to a lower-tier level).
What it avoids is the "valley" - a path that goes up and then down through level
tiers without proper hierarchical or commercial rationale, such as
going from a lower-tier level up to a higher-tier and then back down
to another lower-tier level.
Maybe few summary words could be provided beyond the reference provided.

1307 5.3.  Fallen Leaf Problem

[minor] The text illustrates the complexity of managing a fabric network
under the RIFT protocol, emphasizing the need for dynamic response
strategies to maintain connectivity and ensure robust network performance
in various failure scenarios.

Can an easy to digest summary of the dynamic response by RIFT to
the fallen leaf problem be added to the section to guide the reader
into section 5.4 and 5.5?

1590   RIFT supports any combination of IPv4 and IPv6 addressing on the
1591   fabric with the additional capability for forwarding paths that are
1592   capable of forwarding IPv4 packets in presence of IPv6 addressing
1593   only.

[major#1] does RIFT care about address scopes used? i.e. Link-locals or unnumbered
interfaces using interface id's, etc
[major#2] Does RIFT allow one side to be IPv4-only and the other side IPv6-only?
There is a table later explaining some aspects, but that may not to fully
conform to the perceived allowed addressing combinations. 

1600   schema Appendix B.2 is used unless configured otherwise.  LIEs MUST
1601   be sent with an IPv4 Time to Live (TTL) or an IPv6 Hop Limit (HL) of
1602   either 1 or 255 to prevent RIFT information reaching beyond a single
1603   L3 next-hop in the topology.  LIEs SHOULD be sent with network

[major] what hapens if LIE is sent with another TTL? silently ignored or error message
returned or something else??

1624   A simplified version MAY be implemented on platforms with limited or
1625   no multicast support (e.g.  IoT devices) by sending and receiving LIE
1626   frames on IPv4 subnet broadcast addresses or IPv6 all routers
1627   multicast address.  However, this technique is less optimal and
1628   presents a wider attack surface from a security perspective.

[minor] i assumed that RIFT find applicability in fat tree architectures. These architecture
tend not to be IoT devices. This make me wonder if this paragraph is needed?

1690       Table 1: Control Plane Behavior for Neighbor AF Combinations

[minor] Why is the IPv4,IPv6 -> IPv4 not included in this table? the IPv4,IPv6 -> IPv6 is
included however.

1757   1.  the neighboring node is running the same major schema version as
1758       indicated in the _major_version_ element in _PacketHeader_ *and*

[major] the difference between a RIFT version number and the schema version is unclear.
I may missed reading it when going through the document. What about an text blob about Thrift
schema version in section 2 to provide context about 'what-is-this-schema-version' used
with RIFT KV datastore and how it differs from RIFTversion number.

1767   4.  (the advertised MTU values in the _LiePacket_ element match on
1768       both sides while a missing MTU in the _LiePacket_ element is
1769       interpreted as _default_mtu_size_) *and*

[major] i have been exposed to loads of troubleshooting and HW troubles
when MTU is mentioned with protocols. Also the MRU (Maximum Receive Unit) is
a property different as the MTU. Is it assumed that L2 encaps play a role in the MTU?

Accordingly, MTU can be seen in Different Contexts. Which ones is implied for RIFT?
Ethernet: The standard MTU for Ethernet is typically 1500 bytes.
Internet (IPv4 and IPv6): For internet traffic, the MTU considerations
become more complex due to the need to traverse multiple networks of
potentially varying capabilities.

4135 6.7.  Optional Zero Touch Provisioning (ZTP)

4137   Each RIFT node can operate in zero touch provisioning (ZTP) mode,
4138   i.e. it has no configuration (unless it is a ToF or it is explicitly
4139   configured to operate in the overall topology as leaf and/or support
4140   leaf-2-leaf procedures) and it will fully configure itself after
4141   being attached to the topology.  Configured nodes and nodes operating
4142   in ZTP can be mixed and will form a valid topology if achievable.

[major] in DC environment security is important. In some DCs i visited each device
plugged into the network is authenticated before allowed being connected.

Maybe the ZTP used for device security is a different ZTP to be used for
RIFT and they can be considered as ships-in-the-night solutions?.

5350   RIFT MAGIC:
5351       16 bits.  Constant value of 0xA1F7 that allows easy classification
5352       of RIFT packets independent of the UDP port used.

[minor] Out of interest, why is this particular number chosen? What happens if
a different value is encoded? will the RIFT MAGIC number have secret RIFT Protocol Versioning embedded?

5501   There in no mechanism to convert a security envelope for the same Key
5502   ID from one algorithm to another once the envelope is operational.

[minor] "There in" looks as a typo. Not sure if there are few words misisng.

[Ballot comment]
Thank you for the work on this document.

I was going to comment on the lack of expert guidelines (re the IANA registries with Expert review policy), but I see Roman has already commented on that, so I support his DISCUSS. I also see that there used to be a section for Expert review guidance in v-20, but it got removed, why was that?

Also I would suggest to add a column Reference for all the newly created IANA registries (that can be done easily with one sentence in Section 10.2, so that it applies to all of them).

[Ballot comment]
Thanks for working on this document.

This specification does not bring transport protocol related issues as far as I can see. However, I have noted three issues which are already captured in Gunter's discuss 1 and 2, and Roman's IANA issues. I am supporting their discusses.

[Ballot comment]
I support Roman's DISCUSS position about the IANA registries.  Also, the MUST in 10.2.4 seems inappropriate; why isn't this part of the protocol portion of the document?  And lastly, are there any syntax rules to the names in these registries that should be specified with the registries?  Some of them are snake-case, some are camel-case.

I also support Gunter's DISCUSS position regarding normative text in appendices.

I'm not certain about use of SHOULD [NOT] and [NOT] RECOMMENDED in lots of places.  It seems in many spots that it's used to mean "You really ought to [not] do this", but it doesn't really address why an implementer would choose otherwise which is useful guidance to include.  That sometimes means it should really be a MUST [NOT].  You might consider reviewing them, even though I realize there are over 50.

For example, I made note of these four before deciding to make the above more general comment:

* In 6.3.3.1.1, why is that only a SHOULD?  What happens if I don't do this?

* I'm unclear on what the SHOULD in 6.3.4 is telling me I need to consider doing, or have a good reason not to do.

* What's the effect of not doing what the SHOULDs in 6.3.5 say?

* 6.3.8, same question.

[Ballot comment]
I am supporting Romans', Gunter's #2, #3, #4, and Mahesh's DISUCSS.

Also, massive thanks to Nagendra Kumar Nainar for the OpsDir - this was a very large and complex document to review, so extra thanks for taking it on!


Other than that, I just have some nits to offer:
O: In other words, "bottom" levels are flooding their link-state
information in the "northern" direction while each node generates
under normal conditions a "default route" and floods it in the
"southern" direction.
P: "In other words, "bottom" levels flood their" -- normalize with rest of sentence.


O: "This type of protocol allows naturally for highly desirable address aggregation."
P: "This type of protocol naturally supports highly desirable address aggregation." -- or similar. "allows naturally for" is clumsy.

O: "The protocol does further provide:"
P: "The protocol further provides:"

O: "When the "bottom" of the fabric is considered, or in other words the
  leaves, the topology is basically empty and, under normal
  conditions, the leaves hold a load balanced default route to the
  next level."
P: "When the "bottom" (or, in other words leaves) of the fabric is considered, the topology is basically empty and, under normal
  conditions, the leaves hold a load balanced default route to the
  next level."

O: "First, it introduces RIFT's packet format content in the form of a
normative Thrift model given in Appendix B.3 carried in according
security envelope as described" -- "carried in according security envelope" is unparsable (by me at least :0))

O: "Second, the Thrift model component is a prelude to understanding the RIFT's inherent security features as defined in both security models part (Section 6.9) and the security segment (Section 9)."
C: I found this sentence confusing -- perhaps you meant "prerequisite" not "prelude"? And s/understanding the RIFT's/understanding RIFT's/


O: "For other readers, the following sections provide a more detailed understanding of the fundamental properties and highlight some additional benefits of RIFT such as link state packet formats, efficient flooding, synchronization,..."
C: I don't think that "link state packet formats" are a "benefit"

O: "Some failure scenarios with partial routing information cause nodes to lose the required downstream reachability to a destination and forcing traffic to utilize routes that traverse higher levels in the fabric in order to turn south again using a different to resolve reachability"
C: s/destination and forcing traffic/destination and force traffic/ (or "destination,forcing traffic"). Also "turn south again using a different to resolve reachability" (this seems to be missing a word.

O: "In case the Clos fabric input and output stages are analogous,
  the fabric can be "folded" to build a "superspine" or top which
  is called the ToF in this document".
C: I don't really think that "analogous" is the right word here - perhaps "symmetric"? That's not it either, but I think it is closer? (I knew the right word when initially reading this, but it's now gone out of my head :-))

O: "LIEs MUST
  be sent with an IPv4 Time to Live (TTL) or an IPv6 Hop Limit (HL) of
  either 1 or 255 to prevent RIFT information reaching beyond a single
  L3 next-hop in the topology."
Erm, I think that you need more text here -- if they are sent with a TTL of 255, then the received has to know to only accept 254 and not forward (GTSH).

O: "in the schema type _RouteType_. Table Table 5 contains" Repeated "Table"

O: "rollover, or it can be configured for a infinite time period." - s/a/an/

O: "origin Key ID is only protected by the, here assumed to be " -- erm, what now? I think you are missing a word or two here...

O: "Not preferred route so ignore end if end if end for end for Figure 19: " - erm....

[Ballot comment]
I am supporting Romans', Gunter's #2, #3, #4, and Mahesh's DISUCSS.

Other than that, I just have some nits to offer:
O: In other words, "bottom" levels are flooding their link-state
information in the "northern" direction while each node generates
under normal conditions a "default route" and floods it in the
"southern" direction.
P: "In other words, "bottom" levels flood their" -- normalize with rest of sentence.


O: "This type of protocol allows naturally for highly desirable address aggregation."
P: "This type of protocol naturally supports highly desirable address aggregation." -- or similar. "allows naturally for" is clumsy.

O: "The protocol does further provide:"
P: "The protocol further provides:"

O: "When the "bottom" of the fabric is considered, or in other words the
  leaves, the topology is basically empty and, under normal
  conditions, the leaves hold a load balanced default route to the
  next level."
P: "When the "bottom" (or, in other words leaves) of the fabric is considered, the topology is basically empty and, under normal
  conditions, the leaves hold a load balanced default route to the
  next level."

O: "First, it introduces RIFT's packet format content in the form of a
normative Thrift model given in Appendix B.3 carried in according
security envelope as described" -- "carried in according security envelope" is unparsable (by me at least :0))

O: "Second, the Thrift model component is a prelude to understanding the RIFT's inherent security features as defined in both security models part (Section 6.9) and the security segment (Section 9)."
C: I found this sentence confusing -- perhaps you meant "prerequisite" not "prelude"? And s/understanding the RIFT's/understanding RIFT's/


O: "For other readers, the following sections provide a more detailed understanding of the fundamental properties and highlight some additional benefits of RIFT such as link state packet formats, efficient flooding, synchronization,..."
C: I don't think that "link state packet formats" are a "benefit"

O: "Some failure scenarios with partial routing information cause nodes to lose the required downstream reachability to a destination and forcing traffic to utilize routes that traverse higher levels in the fabric in order to turn south again using a different to resolve reachability"
C: s/destination and forcing traffic/destination and force traffic/ (or "destination,forcing traffic"). Also "turn south again using a different to resolve reachability" (this seems to be missing a word.

O: "In case the Clos fabric input and output stages are analogous,
  the fabric can be "folded" to build a "superspine" or top which
  is called the ToF in this document".
C: I don't really think that "analogous" is the right word here - perhaps "symmetric"? That's not it either, but I think it is closer? (I knew the right word when initially reading this, but it's now gone out of my head :-))

O: "LIEs MUST
  be sent with an IPv4 Time to Live (TTL) or an IPv6 Hop Limit (HL) of
  either 1 or 255 to prevent RIFT information reaching beyond a single
  L3 next-hop in the topology."
Erm, I think that you need more text here -- if they are sent with a TTL of 255, then the received has to know to only accept 254 and not forward (GTSH).

O: "in the schema type _RouteType_. Table Table 5 contains" Repeated "Table"

O: "rollover, or it can be configured for a infinite time period." - s/a/an/

O: "origin Key ID is only protected by the, here assumed to be " -- erm, what now? I think you are missing a word or two here...

O: "Not preferred route so ignore end if end if end for end for Figure 19: " - erm....

[Ballot comment]
I am relying on the routing ADs for the bulk of the review, and will focus on the management part of the draft.

-------------------------------------------------------------------------------
COMMENT
-------------------------------------------------------------------------------

Section 6.9.1, paragraph 13
>    For the cases outlined above, RIFT has two approaches to enforce that
>    a local port is connected to the correct port on the correct remote
>    node.  One approach is to piggy-back on RIFT's authentication
>    mechanism.  Assuming the provisioning model (e.g.  YANG) is flexible
>    enough, operators can choose to provision a unique authentication key
>    for the following conceptual models:

From an operational perspective, there is mention of the KV store and just this mention of YANG. Is there a plan to have a YANG model to configure the keys, rather than using RIFT to distribute the keys?

It is not clear on the question of YANG being flexible enough for operators to provision a unique authentication key, what the authors are looking for. The choice of keys is entirely dependent on how it is modeled. If the ietf-keychain model is augmented, it allows for keys to be configured for a limited period, with graceful rollover, or it can be configured for an infinite period. Is that the flexibility the authors are referring to?

The document has six authors, which exceeds the recommended author limit. Has
the sponsoring AD agreed that this is appropriate?

Check whether Expert Review is an appropriate registration policy here.

Found terminology that should be reviewed for inclusivity; see
https://www.rfc-editor.org/part2/#inclusive_language for background and more
guidance:

* Term "man"; alternatives might be "individual", "people", "person"
* Term "traditional"; alternatives might be "classic", "classical", "common",
  "conventional", "customary", "fixed", "habitual", "historic",
  "long-established", "popular", "prescribed", "regular", "rooted",
  "time-honored", "universal", "widely used", "widespread"

Found IP blocks or addresses not inside RFC5737/RFC3849 example ranges:
"ff02::a1f7" and "224.0.0.121".

-------------------------------------------------------------------------------
NIT
-------------------------------------------------------------------------------

All comments below are about very minor potential issues that you may choose to
address in some way - or ignore - as you see fit. Some were flagged by
automated tools (via https://github.com/larseggert/ietf-reviewtool), so there
will likely be some false positives. There is no need to let me know what you
did with these suggestions.

Section 1, paragraph 13
> r's Digest This section is an initial guided tour through the document in or
>                              ^^^^^^^^^^^^^^
Make sure that the adjective "initial" is correct. Possibly, it should be an
adverb (typically ~ly) that modifies "guided". Possibly, it should be the first
word in a compound adjective (hyphenated adjective). Possibly, it is correct.

Section 3.1, paragraph 10
>  TIE rather than its direction. Consequently North Node TIEs and South Node T
>                                ^^^^^^^^^^^^
A comma may be missing after the conjunctive/linking adverb "Consequently".

Section 3.1, paragraph 56
> until later in the document. Those information flow constraints create not o
>                              ^^^^^^^^^^^^^^^^^
Did you mean "this information"? "Information" is uncountable (except in
certain legal meanings).

Section 3.1, paragraph 56
> align "on top of each other" in a regular fashion. A word of caution to the r
>                              ^^^^^^^^^^^^^^^^^^^^
Consider replacing this phrase with the adverb "regularly" to avoid wordiness.

Section 5.2.2, paragraph 4
> View of a PoD, K_TOP=8, K_LEAF=6, 90 Degree Turn in E-W Plane from the Previo
>                                  ^^^^^^^^^
When "90-Degree" is used as a modifier, it is usually spelled with a hyphen.

Section 5.2.2, paragraph 35
> ow that such a fallen leaf exists. Hence partitioning without further treatm
>                                    ^^^^^
A comma may be missing after the conjunctive/linking adverb "Hence".

Section 5.3, paragraph 1
> en leaf scenario. Somewhat as a side-effect, the exchange of information ful
>                                ^^^^^^^^^^^
Did you mean "side effect" (=adverse effect, unintended consequence)? Open
compounds are not hyphenated.

Section 5.5, paragraph 1
> dress that is neither the well-known or configured multicast or a broadcast
>                                      ^^
Use "nor" with neither.

Section 5.5, paragraph 2
> endent of the address family they arrive on. The LIE source address may not
>                                  ^^^^^^^^^
The usual preposition after "arrive" is "at", not "on". Did you mean "arrive
at"?

Section 6.2, paragraph 11
> itionally, some sets of actions repeat often and are hence summarized into we
>                                ^^^^^^^^^^^^
The adverb "often" is usually put before the verb "repeat".

Section 6.2, paragraph 21
> ployments. Events: * TimerTick: one second timer tick, i.e., the event is pro
>                                ^^^^^^^^^^
When "one-second" is used as a modifier, it is usually spelled with a hyphen.

Section 6.2.1, paragraph 24
> nt). As an example illustrating a databases holding both representations, th
>                                ^^^^^^^^^^^
The plural noun "databases" cannot be used with the article "a". Did you mean
"a database" or "databases"?

Section 6.2.1, paragraph 49
> tion is expected to use the value of any of the valid TIEs it received as it
>                                  ^^^^^^^^^
Consider simply using "of" instead.



Section 6.3.2, paragraph 11
> EYS: Collection of TIE Headers to be send after processing of the packet REQK
>                                      ^^^^
The past participle is required after "to be".

Section 6.3.3, paragraph 11
> ggregation on failures as described in in Section 6.5 and flooding reduction
>                                    ^^^^^
Possible typo: you repeated a word.

Section 6.3.3.1.3.1, paragraph 1
> uting the network. Each node MUST timeout and clean up the corresponding emp
>                                  ^^^^^^^
The word "timeout" is a noun. The verb is spelled with a space.

Section 6.3.4, paragraph 1
> Flood Repeaters" (FRs), which combined together deliver two or more copies of
>                              ^^^^^^^^^^^^^^^^^
"combined together" is redundant. Use "combined".

Section 6.3.4, paragraph 8
>  */ 5. shuffle individually each subarrays |A_k(N) of cardinality C_k(N) with
>                                  ^^^^^^^^^
The noun should probably be in the singular form.

Section 6.3.8, paragraph 1
> nidirectional links MUST be associated together to confirm bidirectional con
>                            ^^^^^^^^^^^^^^^^^^^
This phrase is redundant. Consider writing "associated".

Section 6.3.9, paragraph 8
> ggregation is non-transitive, i.e., its' effects are always constrained to a
>                                    ^^^^
An apostrophe is never used to form possessive case pronouns. Did you mean:
"its"?

Section 6.3.9, paragraph 9
> he North TIEs are used to find all of prefixes it can reach and the set of ne
>                                ^^^^^^^^^^^^^^^
Consider using "all prefixes" or "all of the prefixes".

Section 6.3.9, paragraph 17
> ptimal routing through such nodes. Hence a node X needs to determine if it c
>                                    ^^^^^
A comma may be missing after the conjunctive/linking adverb "Hence".

Section 6.4, paragraph 5
> ply to determine, for each prefix in an South TIE that originated from adjac
>                                      ^^
Use "a" instead of "an" if the following word doesn't start with a vowel sound,
e.g. "a sentence", "a university".

Section 6.4.1, paragraph 2
> xt_hop_set) to route_database end if if (P in route_database): if route_data
>                                      ^^
Did you mean "is"?

Section 6.4.1, paragraph 6
> / Not preferred route so ignore end if end if end for end for Figure 19: Add
>                                ^^^^^^^^^^^^^
This phrase is duplicated. You should probably use "end if" only once.

Section 6.4.1, paragraph 6
>  route so ignore end if end if end for end for Figure 19: Adding Routes from
>                                ^^^^^^^^^^^^^^^
This phrase is duplicated. You should probably use "end for" only once.

Section 6.5.2.1, paragraph 2
> hereas each node (with possibly exceptions of configured leaves) tries to att
>                                ^^^^^^^^^^^^^
The usual collocation for "exceptions" in this context is "to", not "of". Did
you mean "exceptions to"?

Section 6.5.2.2, paragraph 4
> _top_of_fabric_ schema element. A standards conform RIFT implementation impl
>                                ^^^^^^^^^^^
The plural noun "standards" cannot be used with the article "A". Did you mean
"A standard" or "standards"?

Section 6.6, paragraph 11
>  picking its preferred VOL in a different fashion than always trying to achi
>                            ^^^^^^^^^^^^^^^^^^^^^^
Consider replacing this phrase with the adverb "differently" to avoid
wordiness.

Section 6.6, paragraph 18
> ddown timer expired. * ShortTic: one second timer tick. This event is provide
>                                  ^^^^^^^^^^
When "one-second" is used as a modifier, it is usually spelled with a hyphen.

Section 6.6, paragraph 27
> in the schema type _RouteType_. Table Table 5 contains the route type as der
>                                ^^^^^^^^^^^
Possible typo: you repeated a word.

Section 6.7.1, paragraph 10
>  may move up to 127 times in a 200 millisecond period and the clocks will rem
>                                ^^^^^^^^^^^^^^^
When "200-millisecond" is used as a modifier, it is usually spelled with a
hyphen.

Section 6.7.1, paragraph 12
> ement. 6.8.4.3. Anycast vs. Unicast A unicast prefix can be attached to at m
>                                    ^
Use "An" instead of "A" if the following word starts with a vowel sound, e.g.
"an article", "an hour".

Section 6.7.5, paragraph 31
> ng planes to be easily distinguished among multiple RIFT instances. 6.8.9. Le
>                                      ^^^^^
Do not mix variants of the same word ("among" and "amongst") within a single
text.

Section 6.7.6, paragraph 5
> rollover, or it can be configured for a infinite time period. Is that the fle
>                                      ^
Use "an" instead of "a" if the following word starts with a vowel sound, e.g.
"an article", "an hour".


Section 7.1, paragraph 4
> E origin Key ID is only protected by the, here assumed to be compromised, nod
>                                      ^^^^
Articles like "the" are rarely followed by punctuation. A word may be missing
after "the", or the punctuation mark may not be necessary.

Section 10.2.19, paragraph 5
> g Shen for some of the early discussions around the topic of using IGPs for
>                              ^^^^^^^^^^^^^^^^^^
Did you mean "discussions about"?

IANA questions sent to authors:

- Some tables don't include a "0" value. Should "0" be listed as "Unassigned" (available for registration) or "Reserved"?

- Section 10.2 says "Allocation of new values is always performed via `Expert Review` action." However, this doesn't match the registration procedure tables, which alternate between "Expert Review" and "Specification Required." Both require review by an expert, but "Expert Review" is the name of a specific procedure, as defined in RFC 8126.

- On a related note: in version -20's procedure tables, listing "Standards Action" as the procedure for "Major or Minor Change per Rules in section Appendix B" and "Specification Required" as the procedure for "all other assignments" indicated that the former should be more difficult to register.

However, changing "Standards Action" to "Expert Review" while leaving "Specification Required" in place means that it's now more difficult to register "all other assignments." Is this intentional?

If not, we would recommend leaving Section 10.2's "Allocation of new values is always performed via `Expert Review` action" in place and deleting all of the individual registration procedure tables.

Otherwise, if the registration procedure tables are correct as they are, the line "Allocation of new values is always performed via `Expert Review` action" should either be removed or replaced with something like "Allocation of new values always requires approval by an IESG-designated expert, and in some cases the publication of a specification."

- In several of these registries, the "Description" field is empty for some or all of the registrations. Is this correct? Should the "Description" field be removed from some of these tables (or replaced with an optional "Notes" or "Comments" field, if that's a more appropriate name in those cases)?

- Should all of the registry names begin with "RIFT" (e.g., "RIFT CommonAddressFamilyType")? The TLS WG, for example, had us go back and prepend "TLS" to all of the registry names at https://www.iana.org/assignments/tls-parameters.

- A very minor issue: in tables 47, 51, 53 and 73, one or more descriptions begin with lower-case letters. We don't have a preference, but was this intentional?

[Ballot discuss]
** Figure 16.  (please let me know if I’m misunderstanding the code) The normative ordering methodology that “MUST be implemented” would benefit from further description.  Specifically:

-- This pseudo code opens with “for each TIEPacket:” which suggests that the code nested code block will iterate through a series of TIEPackets.  However, every nested “if/else”, to include the final “else”, results in a “return” that would exit the calling function on the first TIEPacket.  This suggests that only one TIEPacket will ever be processed.  Is that the intent?

-- What are the expected return types from this code block and how would the caller know it?  I observe it could be the enum of the direction, the systemid with the originator, “equal”, and whatever type is returned by “compared” (is that “true”/”false”, “equal”/”not equal”, >/</=)? 

** Section 6.9.3.  Conflicting normative guidance.

(a) 6.9.3.
  Any value in
  the packet following a security fingerprint MUST be used by a
  receiver only after the appropriate fingerprint has been validated
  against the data covered by it and the advertised key.

(b)Section 6.9.3
    Local configuration MAY allow for the envelope's integrity checks to
    be skipped.

(c) Section 6.9.6. 
  Obviously, an implementation MAY choose to stop verifying
  security envelope for the duration of algorithm change to keep the
  adjacency up but since this introduces a security vulnerability
  window, such roll-over SHOULD NOT be recommended.

Statement (a) seems pretty clear that fingerprints must be validated.  Statements (b) and (c) seem to have more relaxed approached.  These appear to be in conflict.

** Section 9.  The document contains no indication of an MTI algorithm to use to generate the fingerprint?  As consequence:
-- How are the security claims in this section able to be evaluated?

-- How is it possible to create an interoperable solution?

Can further guidance be provided?

** Section 10.2.* sets the registration policy for a number of registries as “Expert Review”.  What criteria should the expert be using?

** Section 10.2.*.  A number of registries say “Major or Minor Change per Rules in section Appendix B”.  Where in Appendix B can this guidance found?  The appendix looks like a collection of examples.

[Ballot comment]
Thank you to Robert Sparks for the early GENART review.

** Section 3.1. 
There are number of definitions introduced here that aren’t used later in the document.  For example:

-- North Radix
-- South Radix

This definition is used exactly once:

-- Routing on the Host (RotH)

** Section 3.1.

      As a final
      footnote: Clos terminology often uses the concept of "stage", but
      due to the folded nature of the Fat Tree it is not used from this
      point on to prevent misunderstandings.

That lack of use of “stage” from this point on in the document isn’t strictly true.  It is used in “Superspine, Aggregation/Spine and Edge/Leaf Switches”. 

** Section 6.2.1. Figure 14.  In the HTML, the labels on the edges of the FSM diagram do not render with equal font kerning (i.e., some labels are correctly spaced, other appear “smushed together” say “ValidReflection” between ThreeWay and TwoWay)

** Section 6.9.3.  Outer Key ID and TE Origin Key ID.  The description of both of these fields says “This implies key type and algorithm.”  What does that mean?

** Section 6.9.3. 
      To clarify,
      a common corner case when this value is set to 0 is when it
      signifies an empty (0 bytes long) security fingerprint.

Why would a 0 fingerprint be permitted?  How does one tell the difference between such a fingerprint and an on-path attacker who stripped it from the packet?

** Figure 14.  HTML version.  On NewNeighbor and MultipleNeighbors in TwoWay should go to MultipleNeighborsWait.  The arrow for that in the figure is not labeled.

** Section 9.7.
  A node can try to inject LIE packets observing a conversation on the
  wire by using the outer Key ID albeit it cannot generate valid hashes
  in case it changes the integrity of the message so the only possible
  attack is DoS due to excessive LIE validation.

Is this “hashes” or “signatures”?

** Section 10.2.*.  Why don’t the description column of the following registries contain text: e.g., 10.2.3, 10.2.4, 10.2.6, 10.2.7, 10.2.9, etc.

** Section 10.2.1.  Why is Table 7 registering the draft name as a reference instead of the RFC?

[Ballot comment]

# Éric Vyncke, INT AD, comments for draft-ietf-rift-rift-22

Thank you for the work put into this document. It is very expansive with a University book reading, thanks for the many SVG graphics even if some were not really clear to me, section 5 would have benefited from even more graphics.

As the content is somehow outside my area of expertise, my review has focused on the INT area related parts; i.e., I am relying on and trusting my routing AD fellows.

Please find below some non-blocking COMMENT points (but replies would be appreciated even if only for my own education).

Special thanks to Zheng Zhang for the shepherd's detailed write-up including the WG consensus and the not-too-detailed justification of the intended status.

I hope that this review helps to improve the document,

Regards,

-éric


# DISCUSS (blocking)

As noted in https://www.ietf.org/blog/handling-iesg-ballot-positions/, a DISCUSS ballot is a request to have a discussion on the following topics:

##

# COMMENTS (non-blocking)


## Section 1

Figure 1 is missing the node A database (if I read correctly the HTML rendering on Chrome). BTW, really nice of the authors to use SVG graphics.

## Section 6.2

Is there a reason for the unbalance between IPv4 and IPv6 in this section ? Notably in the paragraph starting with `A ThreeWay adjacency (as defined in the glossary)....`.

Thanks for handling LIE sent from a link-local address. Is there any recommendation on the source address selection (i.e., LLA or global or ULA) ?


## Section 6.6

Thanks for the IPv6 examples.

## Section 6.7

I share Gunter Van de Velde's point on the misuse of ZTP in this document, but I also note that the "RIFT ZTP" has its own definition in section 3.1.

## Section 10.1

Should the sub-registries "Local Network Control Block" & "Link-Local Scope Multicast Addresses" also be mentioned ?

## HL 1 or 255

Supporting two values seem really strange for a Proposed Standard document. While I am a big fan of 255, I would have preferred to have a single value (even if it was 1), the WG could have thrown a coin to decide (half-joking).

[Ballot comment]
# Internet AD comments for draft-ietf-rift-rift-21
CC @ekline

* comment syntax:
  - https://github.com/mnot/ietf-comments/blob/main/format.md

* "Handling Ballot Positions":
  - https://ietf.org/about/groups/iesg/statements/handling-ballot-positions/

## Comments

### S3.2

* Figure 3 is excellent, thanks for that.

### S6.2, S6.3.1, S9.2

* TTL/HL of 1 is sometimes used with mulitcast communications, but I have
  found that 255 can be a stronger requirement (and one used in IPv6
  link-local unicast communications).

  Consider standardizing on just 255, and perhaps a add a reference in this
  section to RFC 5082.

  I see some some thought has been given to this in S9.2. Nevertheless,
  my two cents recommendation is to stick with just 255.

### S10.2

* Per RFC 5952 S4.3: "ff02::a1f7".

## Nits

### S1

* "information will be necessary to perform certain algorithms necessary"

  Consider de-dup'ing the "necessary".

### S3.1

* "A radix of a switch is number of switching ports"

  "A radix of a switch is the number of switching ports"

### S5.1

* _super_ nitty, but consider:

  "not flooded East-West or back South again"
  "not flooded East-West nor back South again"

[Ballot discuss]
# Gunter Van de Velde, RTG AD, comments for draft-ietf-rift-rift-21

Thanks to the authors for the epic amount of work put into this document.
Thanks to Loa Andersson, Jonathan Hardwick and Russ White for their valuable RTG DIR reviews
Thanks to Zheng Zhang for the shepherd writeup

Please find some some blocking DISCUSS items (easy to resolve) and a few non-blocking COMMENT points.

Please find https://www.ietf.org/blog/handling-iesg-ballot-positions/ documenting the handling of ballots.

#DISCUSS items
#=============
359   First, it introduces RIFT's packet format content in the form of a
360   normative Thrift model given in Appendix B.3 carried in according

[DISCUSS#1] Normative statements are normally not added in Appendixes. 
Normative content, procedure rules that must be followed to conform
to the standard, is typically found in the main body of the document.

[DISCUSS#2] What is the difference between Distance and Cost used in the document?
These are both in the terminology section, however the difference is unclear (to me).
Both are used within the document extensive. Readers understanding of the
difference is paramount.

[DISCUSS#3] Section 6.2 talks about MTU. I have seen often issues between
neighbors due to (accidental) MTU mismatches. In addition the section
assumes that MTU (transmit) == MRU (receive). Beyond this it is
not specified if this is the L2 MTU or L3 MTU? Often the MTU
on the wire depends upon the L2/L3 encap used. The specifics should be nailed
down on what is intended as the MTU used for RIFT schema.

[DISCUSS#4] Section 6.7 about ZTP. Often the terminology ZTP is associated with
securely adding/booting nodes into a network and guarding none have been
tampered with. ZTP in section 6.7 however seems to describe ZTP from
the perspective of RIFT to allow a node to figure out its level, its
neighbors and its RIFT centric configuration. Unless somewhere else specified
a more explicit RIFT ZTP goals, non-goals and objectives will be help. In section 6.9
some of this is touched upon, however i found the role (current and potential
future extensions) of section 6.7 ZTP somewhat unclear from this perspective.

[Ballot comment]
#GENERIC COMMENTS
#================
##The document is well written in both descriptive and normative style.
In general a wonderful achievement from the authors. i did wonder however
if certain sections can not be made less complicated and with less
wide scope to lower the threshold level for implementers to implement RIFT.

##The document is very long and is an intense complex read. I can
not claim i understand everything in super detail as that would take a
lot more time then available to digest/review this document.

##The security section 9 is a nice security overview of RIFT with loads of details

##The abstract appears to present a rationale for employing Clos or
fat pipe topologies in IP fabrics. However, I would argue that the primary intent
of RIFT is not to justify the use of these specific topologies but is aimed
to be a routing protocol specifically designed for these architectures.

The abstract should provide a glimpse into what RIFT is about. What about
this conceptual rewrite proposal:

    "The document details the Routing in Fat Trees (RIFT) protocol, specifically
    designed for use in Clos and fat-tree network topologies. It aims to reduce
    the complexity and state requirements of the control plane in these networks.
    RIFT addresses both the configuration and operational aspects, enhancing
    efficiency through specialized mechanisms."

##May i suggest add the following introduction summary overview into the introduction
section an overview of the key promised features from RIFT.

Key features of RIFT include:

Topology Awareness: RIFT is tailored for networks with a clear "top" and "bottom",
which is typical of Clos or fat-tree structures. This orientation allows for
optimized data flow management.

Dual Functionality: The protocol functions as a link-state protocol when
routing "north" and as a path-vector protocol when routing "south". This dual
approach helps in efficiently managing the routing information.

Flooding Mechanisms: RIFT employs selective flooding techniques to limit
the spread of routing information to necessary nodes only, thereby
reducing overhead.

Zero Touch Provisioning (ZTP): RIFT supports ZTP, which allows devices
to be configured automatically with minimal manual intervention, leveraging
the structured nature of fat-tree topologies.

Topology Exchange: Through Topology Information Elements (TIEs), RIFT handles
the dissemination of topology and routing information, facilitating both northbound
and southbound routing directions.

Failure Management: The protocol includes mechanisms for handling link
and node failures effectively, using concepts like automatic disaggregation
to maintain network stability and route availability.

Efficient Convergence: RIFT is designed to achieve fast convergence
across large and complex topologies, essential for maintaining high availability
and performance in data center environments.

##YANG data model vs KV store
The document includes a KV datastore, but makes no statement or indication about
YANG models/keys/lists. Seems as a missed opportunity

#DETAILED COMMENTS
#=================

classified as [minor] and [major]

359   First, it introduces RIFT's packet format content in the form of a
360   normative Thrift model given in Appendix B.3 carried in according

[minor] Thrift model: Thrift is a software framework for scalable cross-language
services development. Maybe the pointer to the reference should be used at
first occurrence. There is a reference, but its not added to the first
terminology occurrence but at a later moment.

406   Section 7 contains a set of comprehensive examples that show how RIFT
407   contains the impact of failures to only the required set of nodes.
408   It should also help cement some of RIFT's core concepts in the
409   reader's mind.

[minor] Should section 7 be better located in an informative appendix
to reduce the normative part of the RIFT procedures

411   Last, but not least, RIFT has other optional capabilities.  One
412   example is the key-value data-store, which enables RIFT to advertise
413   data post-convergence in order to bootstrap higher levels of
414   functionality (e.g. operational telemetry).  Those are covered in
415   Section 6.8.

[minor] KV store seems close aligned with how the yang model will look like.
However, the word yang only appears once for a different purpose. intentional?

452   Clos/Fat Tree:
453       This document uses the terms Clos and Fat Tree interchangeably
454       where it always refers to a folded spine-and-leaf topology with
455       possibly multiple Points of Delivery (PoDs) and one or multiple
456       Top of Fabric (ToF) planes.  Several modifications such as leaf-
457       2-leaf shortcuts and multiple level shortcuts are possible and
458       described further in the document.

[minor] It would be useful to at least introduce once what is exactly a fat
tree topology. This seems as a fine location for that purpose.
"A fat tree topology is a structured network design that is commonly
used in large-scale and high-performance computing environments, including
data centers. This topology is a variation of the tree topology, characterized by
increased bandwidth closer to the root of the tree where traffic
concentration is higher."

460   Cost:
461       The sum of metrics between two nodes.
...
479   Distance:
480       The sum of costs (bound by infinite distance) between two nodes.

[major] I have no idea what the difference between Cost and Distance is based
upon this description. Can this be explained better?

505   Leaf-to-Leaf Shortcuts (L2L):
506       East-West links at leaf level will need to be differentiated from
507       East-West links at other levels.

[minor] risk for Terminology confusion. A "shortcut" typically, especially used
with MPLS, refers to a technique used to optimize the path that data
takes through a network, potentially bypassing certain nodes or segments
to improve performance, reduce latency, or manage bandwidth more effectively.
The shortcut here seems something else? is shortcut the best term to
use for this?

847   the overhead of building an update per adjacency.  For the moment
848   describing the East-West direction is left out.

[minor] "left out" of the RIFT specification or out of the current section?

860   reachability information from multiple directions.  Its computation
861   principles (south forwarding direction is always preferred) leads to
862   valley-free [VFR] forwarding behavior.  And since valley free routing
863   is loop-free, it can use all feasible paths.  This is another highly

[minor] i was not familiar with the term Valley-Free routing.
I did some research and found that in valley-free routing, a route is considered
valid if it only traverses paths that go up the hierarchy (from a lower-tier level
to a higher-tier level) or horizontally (between levels of the same tier), and then
potentially down the hierarchy (from a higher-tier level to a lower-tier level).
What it avoids is the "valley" - a path that goes up and then down through level
tiers without proper hierarchical or commercial rationale, such as
going from a lower-tier level up to a higher-tier and then back down
to another lower-tier level.
Maybe few summary words could be provided beyond the reference provided.

1307 5.3.  Fallen Leaf Problem

[minor] The text illustrates the complexity of managing a fabric network
under the RIFT protocol, emphasizing the need for dynamic response
strategies to maintain connectivity and ensure robust network performance
in various failure scenarios.

Can an easy to digest summary of the dynamic response by RIFT to
the fallen leaf problem be added to the section to guide the reader
into section 5.4 and 5.5?

1590   RIFT supports any combination of IPv4 and IPv6 addressing on the
1591   fabric with the additional capability for forwarding paths that are
1592   capable of forwarding IPv4 packets in presence of IPv6 addressing
1593   only.

[major#1] does RIFT care about address scopes used? i.e. Link-locals or unnumbered
interfaces using interface id's, etc
[major#2] Does RIFT allow one side to be IPv4-only and the other side IPv6-only?
There is a table later explaining some aspects, but that may not to fully
conform to the perceived allowed addressing combinations. 

1600   schema Appendix B.2 is used unless configured otherwise.  LIEs MUST
1601   be sent with an IPv4 Time to Live (TTL) or an IPv6 Hop Limit (HL) of
1602   either 1 or 255 to prevent RIFT information reaching beyond a single
1603   L3 next-hop in the topology.  LIEs SHOULD be sent with network

[major] what hapens if LIE is sent with another TTL? silently ignored or error message
returned or something else??

1624   A simplified version MAY be implemented on platforms with limited or
1625   no multicast support (e.g.  IoT devices) by sending and receiving LIE
1626   frames on IPv4 subnet broadcast addresses or IPv6 all routers
1627   multicast address.  However, this technique is less optimal and
1628   presents a wider attack surface from a security perspective.

[minor] i assumed that RIFT find applicability in fat tree architectures. These architecture
tend not to be IoT devices. This make me wonder if this paragraph is needed?

1690       Table 1: Control Plane Behavior for Neighbor AF Combinations

[minor] Why is the IPv4,IPv6 -> IPv4 not included in this table? the IPv4,IPv6 -> IPv6 is
included however.

1757   1.  the neighboring node is running the same major schema version as
1758       indicated in the _major_version_ element in _PacketHeader_ *and*

[major] the difference between a RIFT version number and the schema version is unclear.
I may missed reading it when going through the document. What about an text blob about Thrift
schema version in section 2 to provide context about 'what-is-this-schema-version' used
with RIFT KV datastore and how it differs from RIFTversion number.

1767   4.  (the advertised MTU values in the _LiePacket_ element match on
1768       both sides while a missing MTU in the _LiePacket_ element is
1769       interpreted as _default_mtu_size_) *and*

[major] i have been exposed to loads of troubleshooting and HW troubles
when MTU is mentioned with protocols. Also the MRU (Maximum Receive Unit) is
a property different as the MTU. Is it assumed that L2 encaps play a role in the MTU?

Accordingly, MTU can be seen in Different Contexts. Which ones is implied for RIFT?
Ethernet: The standard MTU for Ethernet is typically 1500 bytes.
Internet (IPv4 and IPv6): For internet traffic, the MTU considerations
become more complex due to the need to traverse multiple networks of
potentially varying capabilities.

4135 6.7.  Optional Zero Touch Provisioning (ZTP)

4137   Each RIFT node can operate in zero touch provisioning (ZTP) mode,
4138   i.e. it has no configuration (unless it is a ToF or it is explicitly
4139   configured to operate in the overall topology as leaf and/or support
4140   leaf-2-leaf procedures) and it will fully configure itself after
4141   being attached to the topology.  Configured nodes and nodes operating
4142   in ZTP can be mixed and will form a valid topology if achievable.

[major] in DC environment security is important. In some DCs i visited each device
plugged into the network is authenticated before allowed being connected.

Maybe the ZTP used for device security is a different ZTP to be used for
RIFT and they can be considered as ships-in-the-night solutions?.

5350   RIFT MAGIC:
5351       16 bits.  Constant value of 0xA1F7 that allows easy classification
5352       of RIFT packets independent of the UDP port used.

[minor] Out of interest, why is this particular number chosen? What happens if
a different value is encoded? will the RIFT MAGIC number have secret RIFT Protocol Versioning embedded?

5501   There in no mechanism to convert a security envelope for the same Key
5502   ID from one algorithm to another once the envelope is operational.

[minor] "There in" looks as a typo. Not sure if there are few words misisng.

[Ballot comment]
# Orie Steele, ART AD, comments for draft-ietf-rift-rift-21
CC @OR13

This review is in the ["IETF Comments" Markdown format][ICMF].
You can use the [`ietf-comments` tool][ICT] to automatically convert this review into
individual GitHub issues, or using this [online validator](https://mnot.github.io/ietf-comments/).

Line numbers are generated with this:
https://author-tools.ietf.org/api/idnits?url=https://www.ietf.org/archive/id/draft-ietf-rift-rift-21.txt&submitcheck=True

## Comments

```
1458 Figure 13: Using rings to bring all planes and at the ToF bind them
```
love this.

## Nits

### List Formatting

```
1774   6.  [

1776           i) the node is at _leaf_level_ value and has no _ThreeWay_
1777           adjacencies already to nodes at Highest Adjacency _ThreeWay_
1778           (HAT as defined later in Section 6.7.1) with level different
1779           than the adjacent node *or*

1781           ii) the node is not at _leaf_level_ value and the neighboring
1782           node is at _leaf_level_ value *or*

1784           iii) both nodes are at _leaf_level_ values *and* both indicate
1785           support for Section 6.8.9 *or*
1786           iv) neither node is at _leaf_level_ value and the neighboring
1787           node is at most one level difference away

1789       ].
```

The use of brackets and absence of sub bullets, is slightly confusing.

### Text based emphasis

```
1723   The protocol does *not* support selective disabling of address
1724   families after adjacency formation, disabling IPv4 forwarding
```

I'm *not* a huge fan or text based emphasis, it does not translate well into HTML.

### Spelling

```
715   Zero Touch Provisioning (ZTP):
716       Optional RIFT mechanism which allows the automatic derivation of
717       node levels based on minimum configuration.  Such a mininum
718       configuration consists solely of ToFs being configured as such.
```

mininum -> minimum

Document History
1. Does the working group (WG) consensus represent the strong concurrence of a
few individuals, with others being silent, or did it reach broad agreement?
  The WG consensus is solid.

2. Was there controversy about particular points, or were there decisions where
the consensus was particularly rough?
  No.

3. Has anyone threatened an appeal or otherwise indicated extreme discontent? If
so, please summarize 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.

4. For protocol documents, are there existing implementations of the contents of
the document? Have a significant number of potential implementers indicated
plans to implement? Are any existing implementations reported somewhere,
either in the document itself (as RFC 7942 recommends) or elsewhere
(where)?
  Yes. At least two implementations existed.

Additional Reviews
5. Do the contents of this document closely interact with technologies in other
IETF working groups or external organizations, and would it therefore benefit
from their review? Have those reviews occurred? If yes, describe which
reviews took place.
  No. The contents of this document have no closely interact with technologies
in other IETF WG or external organizations.

6. Describe how the document meets any required formal expert review criteria,
such as the MIB Doctor, YANG Doctor, media type, and URI type reviews.
  No formal review required.

7. If the document contains a YANG module, has the final version of the module
been checked with any of the recommended validation tools for syntax and
formatting validation? If there are any resulting errors or warnings, what is
the justification for not fixing them at this time? Does the YANG module
comply with the Network Management Datastore Architecture (NMDA) as specified
in RFC 8342?
  No.

8. Describe reviews and automated checks performed to validate sections of the
final version of the document written in a formal language, such as XML code,
BNF rules, MIB definitions, CBOR's CDDL, etc.
  Thrift compilers have successfully generated automatic code from the
Information Elements Schema defined in Appendix B, which are used in two
interoperable implementations.

Document Shepherd Checks
9. Based on the shepherd's review of the document, is it their opinion that this
document is needed, clearly written, complete, correctly designed, and ready
to be handed off to the responsible Area Director?
  This document is ready for publication.  The document shepherd has done a
complete and general review of the Document. All issues that were raised in the
working group have been addressed. A new version (-17) with nits modification
is going to be published. This document is ready to be submitted to IESG.

10. Several IETF Areas have assembled lists of common issues that their
reviewers encounter. For which areas have such issues been identified
and addressed? For which does this still need to happen in subsequent
reviews?
  The IETF Areas’ comments have been addressed.

11. What type of RFC publication is being requested on the IETF stream (Best
Current Practice, Proposed Standard, Internet Standard,
Informational, Experimental or Historic)? Why is this the proper type
of RFC? Do all Datatracker state attributes correctly reflect this intent?
  The intended status is Proposed Standards. It is indicated in the header.
It matches with the content of the Document which defines protocol procedures.
All Datatracker state attributes correctly reflect this intent.

12. Have reasonable efforts been made to remind all authors of the intellectual
property rights (IPR) disclosure obligations described in BCP 79? To
the best of your knowledge, have all required disclosures been filed? If
not, explain why. If yes, summarize any relevant discussion, including links
to publicly-available messages when applicable.
  Yes. All Authors and Contributors have made a statement regarding their
knowledge of IPR which would relate to this Document. Six IPR disclosures
have been made against this Document. The WG did not raise any issue with
the existence of these IPR.

13. Has each author, editor, and contributor shown their willingness to be
listed as such? If the total number of authors and editors on the front page
is greater than five, please provide a justification.
  The number of authors exceeds five. The sixth co-author Jordan Head is the
main editor of version 16. He did great job to improve the draft.

14. Document any remaining I-D nits in this document. Simply running the idnits
tool is not enough; please review the "Content Guidelines" on
authors.ietf.org. (Also note that the current idnits tool generates
some incorrect warnings; a rewrite is underway.)
  Some idnits noise exist, but only editorial changes needed.

15. Should any informative references be normative or vice-versa? See the IESG
Statement on Normative and Informative References.
  No.

16. List any normative references that are not freely available to anyone. Did
the community have sufficient access to review any such normative
references?
  The community has sufficient access to review such normative references.

17. Are there any normative downward references (see RFC 3967 and BCP
97) that are not already listed in the DOWNREF registry? If so,
list them.
  No.

18. Are there normative references to documents that are not ready to be
submitted to the IESG for publication or are otherwise in an unclear state?
If so, what is the plan for their completion?
  No.

19. Will publication of this document change the status of any existing RFCs? If
so, does the Datatracker metadata correctly reflect this and are those RFCs
listed on the title page, in the abstract, and discussed in the
introduction? If not, explain why and point to the part of the document
where the relationship of this document to these other RFCs is discussed.
  No.

20. 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 aspects of the document requiring IANA assignments are
associated with the appropriate reservations in IANA registries. Confirm
that any referenced IANA registries have been clearly identified. Confirm
that each newly created IANA registry specifies its initial contents,
allocations procedures, and a reasonable name (see RFC 8126).
  There was a long thread with the AD about registry naming/structure.
Aligned with his suggestions, the document lists IANA registries to be created,
with reasonable names, detailed specification of initial contents and procedures
for future allocations (expert review).

21. List any new IANA registries that require Designated Expert Review for
future allocations. Are the instructions to the Designated Expert clear?
Please include suggestions of designated experts, if appropriate.
  Tony Przygienda, Bruno Rijsman and Pascal Thubert are suggested as the
IANA Experts for the new registries.

22. RIFT is uniquely justified to have more than 5 authors given its wide
scope and long time in development of specification. The authors listed all
contributed significant ideas or parts of the spec or participated heavily
in formatting/editing of the draft over long periods of times. I recommend
to add each of the authors for the reasons given below:
Jordan did huge amount of lifting as editor incl. svg etc.
Pascal contributed tons, whole theoretical framework/language of fabric,
mobility, negative disaggregation fib especially, reworked whole flood
reduction.
Bruno wrote open source and was on all early calls, found FSM problems.
Dmitry was on all early calls, contributed lots practical considerations
from operation's side.
'Alankar (which will be added again) the same, on all early things,
contributed lots original ideas.

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

IANA has completed its review of draft-ietf-rift-rift-20. If any part of this review is inaccurate, please let us know.

IANA has a question about the first and fourth actions requested in the IANA Considerations section of this document.

First, in the Service Name and Transport Protocol Port Number Registry located at:

https://www.iana.org/assignments/service-names-port-numbers/

the temporary registrations for:

Service Name: rift-lies
Port Number: 914
Transport Protocol: udp
Description: Routing in Fat Trees Link Information Elements
Assignee: IESG
Contact: IETF Chair
Reference: [ RFC-to-be ]

Service Name: rift-ties
Port Number: 915
Transport Protocol: udp
Description: Routing in Fat Trees Topology Information Elements
Assignee: IESG
Contact: IETF Chair
Reference: [ RFC-to-be ]

will be made permanent, their assignees and contacts updated, and their references changed to [ RFC-to-be ].

IANA Comment -> Would the authors be able to add the the templates from RFC 6335, Section 8.1 to Section 10.1 of this I-D?

Second, in the IPv4 Multicast Address Space registry group located at:

https://www.iana.org/assignments/multicast-addresses/

the temporary registration for:

Address: 224.0.0.121
Description: ALL_V4_RIFT_ROUTERS

will be made permanent and its reference changed to [ RFC-to-be ].

Third, in the IPv6 Multicast Address Space Registry group located at:

https://www.iana.org/assignments/ipv6-multicast-addresses/

the temporary registration for:

Address: FF02::A1F7
Description: ALL_V6_RIFT_ROUTERS

will be made permanent and its reference changed to [ RFC-to-be ].

Fourth, while the new top-level Routing in Fat Trees registry makes sense to IANA, the instructions in section 10.2 of the IANA Considerations Section appear to be contradictory. Section 10.2 says that "Allocation of new values is always performed via `Expert Review` action." However, nearly every registry in the subsequent section provides conflicting registration procedure instructions (see RFC8126). Which are the correct instructions for these registries?

In addition, it would be helpful to have explicit titles for the registries in each subsection of Section 10.2.

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.

For definitions of IANA review states, please see:

https://datatracker.ietf.org/help/state/draft/iana-review

Thank you,

David Dong
IANA Services Sr. Specialist

The following Last Call announcement was sent out (ends 2024-03-05):

From: The IESG
To: IETF-Announce
CC: Zheng Zhang , aretana.ietf@gmail.com, draft-ietf-rift-rift@ietf.org, james.n.guichard@futurewei.com, rift-chairs@ietf.org, rift@ietf.org, zhang.zheng@zte.com.cn
Reply-To: last-call@ietf.org
Sender:
Subject: Last Call:  (RIFT: Routing in Fat Trees) to Proposed Standard


The IESG has received a request from the Routing In Fat Trees WG (rift) to
consider the following document: - 'RIFT: Routing in Fat Trees'
  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
last-call@ietf.org mailing lists by 2024-03-05. Exceptionally, comments may
be sent to iesg@ietf.org instead. In either case, please retain the beginning
of the Subject line to allow automated sorting.

Abstract


  This document defines a specialized, dynamic routing protocol for
  Clos and fat tree network topologies optimized towards minimization
  of control plane state as well as minimization of configuration and
  operational complexity.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-rift-rift/


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

  https://datatracker.ietf.org/ipr/2944/
  https://datatracker.ietf.org/ipr/3168/
  https://datatracker.ietf.org/ipr/3343/
  https://datatracker.ietf.org/ipr/3091/
  https://datatracker.ietf.org/ipr/3226/
  https://datatracker.ietf.org/ipr/3167/

Document History
1. Does the working group (WG) consensus represent the strong concurrence of a
few individuals, with others being silent, or did it reach broad agreement?
  The WG consensus is solid.

2. Was there controversy about particular points, or were there decisions where
the consensus was particularly rough?
  No.

3. Has anyone threatened an appeal or otherwise indicated extreme discontent? If
so, please summarize 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.

4. For protocol documents, are there existing implementations of the contents of
the document? Have a significant number of potential implementers indicated
plans to implement? Are any existing implementations reported somewhere,
either in the document itself (as RFC 7942 recommends) or elsewhere
(where)?
  Yes. At least two implementations existed.

Additional Reviews
5. Do the contents of this document closely interact with technologies in other
IETF working groups or external organizations, and would it therefore benefit
from their review? Have those reviews occurred? If yes, describe which
reviews took place.
  No. The contents of this document have no closely interact with technologies
in other IETF WG or external organizations.

6. Describe how the document meets any required formal expert review criteria,
such as the MIB Doctor, YANG Doctor, media type, and URI type reviews.
  No formal review required.

7. If the document contains a YANG module, has the final version of the module
been checked with any of the recommended validation tools for syntax and
formatting validation? If there are any resulting errors or warnings, what is
the justification for not fixing them at this time? Does the YANG module
comply with the Network Management Datastore Architecture (NMDA) as specified
in RFC 8342?
  No.

8. Describe reviews and automated checks performed to validate sections of the
final version of the document written in a formal language, such as XML code,
BNF rules, MIB definitions, CBOR's CDDL, etc.
  Thrift compilers have successfully generated automatic code from the
Information Elements Schema defined in Appendix B, which are used in two
interoperable implementations.

Document Shepherd Checks
9. Based on the shepherd's review of the document, is it their opinion that this
document is needed, clearly written, complete, correctly designed, and ready
to be handed off to the responsible Area Director?
  This document is ready for publication.  The document shepherd has done a
complete and general review of the Document. All issues that were raised in the
working group have been addressed. A new version (-17) with nits modification
is going to be published. This document is ready to be submitted to IESG.

10. Several IETF Areas have assembled lists of common issues that their
reviewers encounter. For which areas have such issues been identified
and addressed? For which does this still need to happen in subsequent
reviews?
  The IETF Areas’ comments have been addressed.

11. What type of RFC publication is being requested on the IETF stream (Best
Current Practice, Proposed Standard, Internet Standard,
Informational, Experimental or Historic)? Why is this the proper type
of RFC? Do all Datatracker state attributes correctly reflect this intent?
  The intended status is Proposed Standards. It is indicated in the header.
It matches with the content of the Document which defines protocol procedures.
All Datatracker state attributes correctly reflect this intent.

12. Have reasonable efforts been made to remind all authors of the intellectual
property rights (IPR) disclosure obligations described in BCP 79? To
the best of your knowledge, have all required disclosures been filed? If
not, explain why. If yes, summarize any relevant discussion, including links
to publicly-available messages when applicable.
  Yes. All Authors and Contributors have made a statement regarding their
knowledge of IPR which would relate to this Document. Six IPR disclosures
have been made against this Document. The WG did not raise any issue with
the existence of these IPR.

13. Has each author, editor, and contributor shown their willingness to be
listed as such? If the total number of authors and editors on the front page
is greater than five, please provide a justification.
  The number of authors exceeds five. The sixth co-author Jordan Head is the
main editor of version 16. He did great job to improve the draft.

14. Document any remaining I-D nits in this document. Simply running the idnits
tool is not enough; please review the "Content Guidelines" on
authors.ietf.org. (Also note that the current idnits tool generates
some incorrect warnings; a rewrite is underway.)
  Some idnits noise exist, but only editorial changes needed.

15. Should any informative references be normative or vice-versa? See the IESG
Statement on Normative and Informative References.
  No.

16. List any normative references that are not freely available to anyone. Did
the community have sufficient access to review any such normative
references?
  The community has sufficient access to review such normative references.

17. Are there any normative downward references (see RFC 3967 and BCP
97) that are not already listed in the DOWNREF registry? If so,
list them.
  No.

18. Are there normative references to documents that are not ready to be
submitted to the IESG for publication or are otherwise in an unclear state?
If so, what is the plan for their completion?
  No.

19. Will publication of this document change the status of any existing RFCs? If
so, does the Datatracker metadata correctly reflect this and are those RFCs
listed on the title page, in the abstract, and discussed in the
introduction? If not, explain why and point to the part of the document
where the relationship of this document to these other RFCs is discussed.
  No.

20. 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 aspects of the document requiring IANA assignments are
associated with the appropriate reservations in IANA registries. Confirm
that any referenced IANA registries have been clearly identified. Confirm
that each newly created IANA registry specifies its initial contents,
allocations procedures, and a reasonable name (see RFC 8126).
  There was a long thread with the AD about registry naming/structure.
Aligned with his suggestions, the document lists IANA registries to be created,
with reasonable names, detailed specification of initial contents and procedures
for future allocations (expert review).

21. List any new IANA registries that require Designated Expert Review for
future allocations. Are the instructions to the Designated Expert clear?
Please include suggestions of designated experts, if appropriate.
  Tony Przygienda, Bruno Rijsman and Pascal Thubert are suggested as the
IANA Experts for the new registries.

Closed request for Early review by INTDIR with state 'Withdrawn': For now, as this document is at -12 and had "not ready/has issues" reviews from other directorates and has not been update since 5/25/2020, assume this document is dead for now.

As required by RFC 4858, this is the current template for the Document
Shepherd Write-Up. Changes are expected over time.

This version is dated 1 November 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?

  The intended status is Proposed Standards. It is indicated in the header.
  It matches with the content of the Document which defines protocol procedures.

(2) The IESG approval announcement includes a Document Announcement Write-Up. Please provide such a Document Announcement Write-Up. Recent examples can be found in the "Action" announcements for approved documents. The approval announcement contains the following sections:

Technical Summary:

    This document defines a specialized, dynamic routing protocol for Clos and fat-tree network topologies optimized towards minimization of configuration and operational complexity.

Working Group Summary:

    The RIFT WG supports the publication of this Document as a Proposed Standard RFC.

Document Quality:

    Several implementations of this technology exist.
    Many reviewers provide comments and suggestions.
    This document is clear and well-written.

Personnel:

    Zheng Zhang is the Document Shepherd.
    Alvaro Retana is the Responsible Area Director.

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

  This document is ready for publication.  The document shepherd has done a complete and general review of the Document.
  All issues that were raised in the working group have been addressed.
  A new version (-12) with nits modification is going to be published.
  This document is ready to be submitted to IESG.

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

  No concerns.

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

  No such reviews needed.

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

  No such concerns, all the outstanding issues have been resolved.

(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?

  All Authors and Contributors have made a statement regarding their knowledge of IPR which would relate to this Document.

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

  Six IPR disclosures have been made against this Document.
  The WG did not raise any issue with the existence of these IPR.

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

  The WG consensus is solid.

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

  No.

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

  No errors were found on the ID nits check, only idnits noise.

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

  No formal review required.

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

  Yes. With one update in version 12 of this document.

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

  No.

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

  No.

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

  No.

(17) Describe the Document Shepherd's review of the IANA considerations section, especially with regard to its consistency with the body of the document. Confirm that all protocol extensions that the document makes are associated with the appropriate reservations in IANA registries. Confirm that any referenced IANA registries have been clearly identified. Confirm that newly created IANA registries include a detailed specification of the initial contents for the registry, that allocations procedures for future registrations are defined, and a reasonable name for the new registry has been suggested (see RFC 8126).

  There was a long thread with the AD about registry naming/structure. Aligned with his suggestions, the document lists IANA registries to be created, with reasonable names, detailed specification of initial contents and procedures for future allocations (expert review).

(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.

  Tony Przygienda, Bruno Rijsman and Pascal Thubert are suggested as the IANA Experts for the new registries.

(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, YANG modules, etc.

  Thrift compilers have successfully generated automatic code from the Information Elements Schema defined in Appendix B, which are used in two interoperable implementations.

(20) If the document contains a YANG module, has the module been checked with any of the recommended validation tools (https://trac.ietf.org/trac/ops/wiki/yang-review-tools) for syntax and formatting validation? If there are any resulting errors or warnings, what is the justification for not fixing them at this time? Does the YANG module comply with the Network Management Datastore Architecture (NMDA) as specified in RFC8342?

  No.

As required by RFC 4858, this is the current template for the Document
Shepherd Write-Up. Changes are expected over time.

This version is dated 1 November 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?

  The intended status is Proposed Standards. It is indicated in the header.
  It matches with the content of the Document which defines protocol procedures.

(2) The IESG approval announcement includes a Document Announcement Write-Up. Please provide such a Document Announcement Write-Up. Recent examples can be found in the "Action" announcements for approved documents. The approval announcement contains the following sections:

Technical Summary:

    This document defines a specialized, dynamic routing protocol for Clos and fat-tree network topologies optimized towards minimization of configuration and operational complexity.

Working Group Summary:

    The RIFT WG supports the publication of this Document as a Proposed Standard RFC.

Document Quality:

    Several implementations of this technology exist.
    Many reviewers provide comments and suggestions.
    This document is clear and well-written.

Personnel:

    Zheng Zhang is the Document Shepherd.
    Alvaro Retana is the Responsible Area Director.

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

  This document is ready for publication.  The document shepherd has done a complete and general review of the Document.
  All issues that were raised in the working group have been addressed.
  A new version (-12) with nits modification is going to be published.
  This document is ready to be submitted to IESG.

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

  No concerns.

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

  No such reviews needed.

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

  No such concerns, all the outstanding issues have been resolved.

(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?

  All Authors and Contributors have made a statement regarding their knowledge of IPR which would relate to this Document.

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

  Six IPR disclosures have been made against this Document.
  The WG did not raise any issue with the existence of these IPR.

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

  The WG consensus is solid.

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

  No.

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

  No errors were found on the ID nits check, only idnits noise.

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

  No formal review required.

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

  Yes. With one update in version 12 of this document.

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

  No.

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

  No.

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

  No.

(17) Describe the Document Shepherd's review of the IANA considerations section, especially with regard to its consistency with the body of the document. Confirm that all protocol extensions that the document makes are associated with the appropriate reservations in IANA registries. Confirm that any referenced IANA registries have been clearly identified. Confirm that newly created IANA registries include a detailed specification of the initial contents for the registry, that allocations procedures for future registrations are defined, and a reasonable name for the new registry has been suggested (see RFC 8126).

  There was a long thread with the AD about registry naming/structure. Aligned with his suggestions, the document lists IANA registries to be created, with reasonable names, detailed specification of initial contents and procedures for future allocations (expert review).

(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.

  Tony Przygienda, Bruno Rijsman and Pascal Thubert are suggested as the IANA Experts for the new registries.

(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, YANG modules, etc.

  Thrift compilers have successfully generated automatic code from the Information Elements Schema defined in Appendix B, which are used in two interoperable implementations.

(20) If the document contains a YANG module, has the module been checked with any of the recommended validation tools (https://trac.ietf.org/trac/ops/wiki/yang-review-tools) for syntax and formatting validation? If there are any resulting errors or warnings, what is the justification for not fixing them at this time? Does the YANG module comply with the Network Management Datastore Architecture (NMDA) as specified in RFC8342?

  No.

As required by RFC 4858, this is the current template for the Document
Shepherd Write-Up. Changes are expected over time.

This version is dated 1 November 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?

  The intended status is Proposed Standards. It is indicated in the header.
  It matches with the content of the Document which defines protocol procedures.

(2) The IESG approval announcement includes a Document Announcement Write-Up. Please provide such a Document Announcement Write-Up. Recent examples can be found in the "Action" announcements for approved documents. The approval announcement contains the following sections:

Technical Summary:

    This document defines a specialized, dynamic routing protocol for Clos and fat-tree network topologies optimized towards minimization of configuration and operational complexity.

Working Group Summary:

    The RIFT WG supports the publication of this Document as a Proposed Standard RFC.

Document Quality:

    Several implementations of this technology exist.
    Many reviewers provide comments and suggestions.
    This document is clear and well-written.

Personnel:

    Zheng Zhang is the Document Shepherd.
    Alvaro Retana is the Responsible Area Director.

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

  This document is ready for publication.  The document shepherd has done a complete and general review of the Document.
  All issues that were raised in the working group have been addressed.
  A new version (-12) with nits modification is going to be published.
  This document is ready to be submitted to IESG.

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

  No concerns.

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

  No such reviews needed.

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

  No such concerns, all the outstanding issues have been resolved.

(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?

  All Authors and Contributors have made a statement regarding their knowledge of IPR which would relate to this Document.

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

  Six IPR disclosures have been made against this Document.
  The WG did not raise any issue with the existence of these IPR.

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

  The WG consensus is solid.

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

  No.

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

  No errors were found on the ID nits check, only idnits noise.

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

  No formal review required.

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

  Yes. With one update in version 12 of this document.

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

  No.

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

  No.

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

  No.

(17) Describe the Document Shepherd's review of the IANA considerations section, especially with regard to its consistency with the body of the document. Confirm that all protocol extensions that the document makes are associated with the appropriate reservations in IANA registries. Confirm that any referenced IANA registries have been clearly identified. Confirm that newly created IANA registries include a detailed specification of the initial contents for the registry, that allocations procedures for future registrations are defined, and a reasonable name for the new registry has been suggested (see RFC 8126).

  The document requests IANA actions.

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

  No.

(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, YANG modules, etc.

  Not applicable.

(20) If the document contains a YANG module, has the module been checked with any of the recommended validation tools (https://trac.ietf.org/trac/ops/wiki/yang-review-tools) for syntax and formatting validation? If there are any resulting errors or warnings, what is the justification for not fixing them at this time? Does the YANG module comply with the Network Management Datastore Architecture (NMDA) as specified in RFC8342?

  No.

As required by RFC 4858, this is the current template for the Document
Shepherd Write-Up. Changes are expected over time.

This version is dated 1 November 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?

  The intended status is Proposed Standards. It is indicated in the header.
  It matches with the content of the Document which defines protocol procedures.

(2) The IESG approval announcement includes a Document Announcement Write-Up. Please provide such a Document Announcement Write-Up. Recent examples can be found in the "Action" announcements for approved documents. The approval announcement contains the following sections:

Technical Summary:

    This document defines a specialized, dynamic routing protocol for Clos and fat-tree network topologies optimized towards minimization of configuration and operational complexity.

Working Group Summary:

    The RIFT WG supports the publication of this Document as a Proposed Standard RFC.

Document Quality:

    Several implementations of this technology exist.
    Many reviewers provide comments and suggestions.
    This document is clear and well-written.

Personnel:

    Zheng Zhang is the Document Shepherd.
    Alvaro Retana is the Responsible Area Director.

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

  This document is ready for publication.  The document shepherd has done a complete and general review of the Document.
  All issues that were raised in the working group have been addressed.
  A new version (-12) with nits modification is going to be published.
  This document is ready to be submitted to IESG.

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

  No concerns.

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

  No such reviews needed.

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

  No such concerns, all the outstanding issues have been resolved.

(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?

  All Authors and Contributors have made a statement regarding their knowledge of IPR which would relate to this Document.

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

  Six IPR disclosures have been made against this Document.
  The WG did not raise any issue with the existence of these IPR.

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

  The WG consensus is solid.

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

  No.

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

  No errors were found on the ID nits check, only idnits noise.

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

  No formal review required.

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

  Yes. With one update in version 12 of this document.

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

  No.

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

  No.

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

  No.

(17) Describe the Document Shepherd's review of the IANA considerations section, especially with regard to its consistency with the body of the document. Confirm that all protocol extensions that the document makes are associated with the appropriate reservations in IANA registries. Confirm that any referenced IANA registries have been clearly identified. Confirm that newly created IANA registries include a detailed specification of the initial contents for the registry, that allocations procedures for future registrations are defined, and a reasonable name for the new registry has been suggested (see RFC 8126).

  The document requests IANA actions.

(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.

  N/A.

(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, YANG modules, etc.

  Not applicable.

(20) If the document contains a YANG module, has the module been checked with any of the recommended validation tools (https://trac.ietf.org/trac/ops/wiki/yang-review-tools) for syntax and formatting validation? If there are any resulting errors or warnings, what is the justification for not fixing them at this time? Does the YANG module comply with the Network Management Datastore Architecture (NMDA) as specified in RFC8342?

  No.