Virtual eXtensible Local Area Network (VXLAN): A Framework for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks
draft-ietf-nvo3-rfc7348bis-11

[Ballot comment]
Thanks for the important work in this document, I simply hope that this widely deployed technology will eventually be a Proposed Standard.

Thanks also for the lengthy discussion to resolve my previous DISCUSS ballot: https://mailarchive.ietf.org/arch/msg/bmwg/KYW_XRJnQawRxK63XOEYgRVWKmU/

# Document Shepherd Write-Up for Group Documents

## 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 document achieved broad working group consensus. Multiple working group
participants reviewed the document during its development and Working Group
Last Call, and comments received during WGLC were addressed by the authors.
Support for publication was expressed by participants representing multiple
vendors and operators. The consensus was not limited to a small set of
contributors.


2. Was there controversy about particular points, or were there decisions
where the consensus was particularly rough?

There were no significant controversies during working group review. Comments
received during review focused on clarification, editorial improvements, and
ensuring consistency with current deployment and implementation practices.
Consensus on the final document was straightforward and did not require any
particularly rough consensus calls.

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 participant has threatened an appeal or expressed extreme discontent with
the document or with the working group process.

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][3] recommends) or
elsewhere (where)?

The document updates an existing specification that has been widely
implemented and deployed. Implementations of the underlying technology exist
from multiple vendors and in open-source software.

RFC 7348 was originally published as an Informational RFC through the
Independent Stream, documenting an already-deployed industry protocol.
Since then, VXLAN has become a foundational encapsulation technology and
subsequent IETF work has identified a need to define extensions that require
assignments within the VXLAN header. The main purpose of this document is to
obsolete RFC 7348, move the VXLAN specification to the IETF stream, establish
the necessary IANA registries for VXLAN header fields, and provide an
authoritative specification under IETF change control. The document preserves
wire-format and behavioural compatibility with RFC 7348 and is not intended to
change deployed VXLAN implementations.

The bis document retains the 'Informational' proposed status of the original document
since it is documenting widely deployed industry protocol rather than specifying
a new standard protocol.

Note that the process of republishing RFC7348 on the IETF stream was done in
collaboration with and with the agreement of the original RFC authors, as
well as the area directors responsible for NVO3 at the time,

## 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.

The document primarily concerns technology within the chartered scope of the
NVO3 working group. VXLAN is widely used as a data plane in Ethernet VPNs
(EVPN) defined by the BESS working group. One of the main motivations of
RFC7348bis is to allow VXLAN to carry an EVPN Group Policy ID, the control
plane extensions being defined in BESS. The work on RSC7348bis was
coordinated with the BESS working group.


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.

The document does not contain MIB modules, YANG modules, media type
registrations, URI registrations, or other constructs requiring formal expert
review. Therefore, no such reviews were 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][4] 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][5]?

This document does not contain any YANG modules.


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.

The document does not contain content written in a formal language such as
YANG, MIB, XML schema, BNF, CDDL, or similar constructs requiring automated
validation.


## 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?

I have reviewed the document in detail and provided comments to the authors,
which were fixed. I believe that it is needed, clearly written, technically
sound, complete, and ready for publication.

10. Several IETF Areas have assembled [lists of common issues that their
reviewers encounter][6]. For which areas have such issues been identified and
addressed? For which does this still need to happen in subsequent reviews?

No outstanding issues identified.

11. What type of RFC publication is being requested on the IETF stream ([Best
Current Practice][12], [Proposed Standard, Internet Standard][13],
[Informational, Experimental or Historic][14])? Why is this the proper type
of RFC? Do all Datatracker state attributes correctly reflect this intent?

The requested publication type is Informational. This is appropriate as the
document describes an existing, widely deployed protocol that was originally
developed outside of the IETF, while allowing the establishment the necessary
IANA registries for VXLAN header fields.

12. Have reasonable efforts been made to remind all authors of the
intellectual property rights (IPR) disclosure obligations described in [BCP
79][7]? 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.

An IPR poll was conducted on the NVO3 list. The working group chairs reminded
the authors of their obligations under BCP 79. There are no IPR disclosures
against either this document or the original RFC.

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 authors and editors have confirmed their willingness to be listed in the
document and are aware of the responsibilities associated with authorship and
editorship.

14. Document any remaining I-D nits in this document. Simply running the
[idnits tool][8] is not enough; please review the ["Content Guidelines" on
authors.ietf.org][15]. (Also note that the current idnits tool generates some
incorrect warnings; a rewrite is underway.)

I have reviewed the document, including idnits output and the IETF content
guidelines. No significant issues remain.


15. Should any informative references be normative or vice-versa? See the
[IESG Statement on Normative and Informative References][16].

The references are correctly classified as normative and informative. No
changes are believed necessary.


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

None. All references are to IETF RFCs.


17. Are there any normative downward references (see [RFC 3967][9] and [BCP
97][10]) that are not already listed in the [DOWNREF registry][17]? If so,
list them.

None. All references are to IETF RFCs.


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?

None. All references are to IETF RFCs.



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.

Publication of this document will obsolete RFC 7843. The Datatracker metadata
correctly reflects this relationship. T he title page, abstract, and
introduction identify the document's relationship to RFC 7843 and explain the
reasons for replacing it.


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][11]).

I have reviewed the IANA Considerations section and found it to be
consistent with the technical specification in the body of the document. The
document requests two IANA actions:

It records the use of the already assigned UDP destination port 4789 for
VXLAN in the Service Name and Transport Protocol Port Number Registry,
consistent with the VXLAN encapsulation described in Section 5.

It creates a new IANA registry named "VXLAN Flags" for the 16 flag bits in
the VXLAN header. The registry is initialized with:

Bits 0-3: Reserved Bit 4: Instance ID (I bit) Bits 5-15: Reserved

The document also identifies the additional reserved fields in the VXLAN
header (bits 16-31 of the first header word and bits 24-31 of the second
word) and specifies that reserved bits and fields MUST be set to zero by
senders and ignored by receivers. Future assignments from the VXLAN Flags
registry are to be made through the IETF Review policy defined in RFC 8126.



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.

The allocation process is by IETF review, and so no designated experts are required.


[1]: https://www.ietf.org/about/groups/iesg/ [2]:
https://www.rfc-editor.org/rfc/rfc4858.html [3]:
https://www.rfc-editor.org/rfc/rfc7942.html [4]:
https://wiki.ietf.org/group/ops/yang-review-tools [5]:
https://www.rfc-editor.org/rfc/rfc8342.html [6]:
https://wiki.ietf.org/group/iesg/ExpertTopics [7]:
https://www.rfc-editor.org/info/bcp79 [8]: https://www.ietf.org/tools/idnits/
[9]: https://www.rfc-editor.org/rfc/rfc3967.html [10]:
https://www.rfc-editor.org/info/bcp97 [11]:
https://www.rfc-editor.org/rfc/rfc8126.html [12]:
https://www.rfc-editor.org/rfc/rfc2026.html#section-5 [13]:
https://www.rfc-editor.org/rfc/rfc2026.html#section-4.1 [14]:
https://www.rfc-editor.org/rfc/rfc2026.html#section-4.2 [15]:
https://authors.ietf.org/en/content-guidelines-overview [16]:
https://www.ietf.org/about/groups/iesg/statements/normative-informative-
references/ [17]: https://datatracker.ietf.org/doc/downref/

[Ballot comment]
Hi Mallik, Dinesh, Larry, Sridhar, and Ali,

The changes [1] and clarifications adequately address all points raised in my initial ballot [2]. Thank you for taking care of the review.

Cheers,
Med

[1] https://author-tools.ietf.org/iddiff?url1=draft-ietf-nvo3-rfc7348bis-05&url2=draft-ietf-nvo3-rfc7348bis-10&difftype=--html

[2] https://mailarchive.ietf.org/arch/msg/nvo3/4f6FVy2I3JhL31n8R-q7rc9elp4/

[Ballot comment]
Thanks to the authors and the WG for their work on this document.

Bringing VXLAN base specification on the IETF stream is a step that I
support wholeheartedly.

Also thanks to Ali for the document updates and responses to address
my concerns and comments from my initial ballot.

[Ballot comment]
Thanks for providing this document. I do not see any transport-protocol related concerns and assume that rate/congestion  control and integrity checks are performed as normal for the encapsulated traffic, if that is so, I have no objection to publication of this specification.

[Ballot comment]
thanks to Charlie K. for the SECDIR review.

I'm also confused as to why this is informational and not Proposed Standard - is this documenting a standard from another entity / what's already in wide spread use?

[Ballot comment]
I strongly support Éric's thorough DISCUSS ballot. Additionally, as a minor phrasing point, I wish that PMTUD wasn't used as an alternative to supporting sufficiently high MTU values along the path (this should really be a "do both" situation in my opinion for defense in depth).

[Ballot discuss]

# Éric Vyncke INT AD comments for draft-ietf-nvo3-rfc7348bis-05
CC @evyncke

Thank you for the work put into this document. I really welcome moving the heavily deployed VXLAN in the IETF stream. I have also checked the diff with RFC 7348 in addition to the bis document.

Please find below some blocking DISCUSS points (easy to address), some non-blocking COMMENT points/nits (replies would be appreciated even if only for my own education).

Special thanks to Matthew Bocci for the shepherd's detailed write-up including the WG consensus and the justification of the intended status.

Please note that Karen O'Donoghue is the Internet directorate reviewer (at my request) and you may want to consider this int-dir review as well when it will be available (no need to wait for it though):
https://datatracker.ietf.org/doc/draft-ietf-nvo3-rfc7348bis/reviewrequest/24827/

I hope that this review helps to improve the document,

Regards,

-éric

Note: this ballot comments follow the Markdown syntax of https://github.com/mnot/ietf-comments/tree/main, i.e., they can be processed by a tool to create github issues.

## DISCUSS (blocking)

As noted in https://datatracker.ietf.org/doc/statement-iesg-handling-ballot-positions-20220121/, a DISCUSS ballot is a request to have a discussion on the points below; I really think that the document would be improved with a change here, but can be convinced otherwise.

### Section 2

Trivial to address but important, please use the correct BCP14 template.

### Section 4.2

What about IPv6 MLD in `Using this mapping, the VTEP can provide IGMP membership reports to the upstream switch/router to join/leave the VXLAN-related IP multicast groups as needed.`?

Similar issue in section 4.3 with `efficient multicast replication within the Layer 2 network can be achieved using IGMP snooping.`

### Section 4.3

`Intermediate routers may fragment encapsulated VXLAN packets due to the larger frame size.` but fragmentation by intermediate routers is not allowed in IPv6.

### Section 5

What is a `valid VXLAN Network ID` in `where Bit 4 is I flag and MUST be set to 1 for a valid VXLAN Network ID (VNI)` ?

What should do a receiving VTEP when this flag is 0 ?

Add an informative reference to RFC 6935 when writing `UDP Checksum: It SHOULD be transmitted as zero`

Also, BCP14 mandates that guidance is required to understand the consequences of a SHOULD, and this guidance is absent in `It SHOULD be transmitted as zero` adding 'for performance reason' would be enough. See also https://datatracker.ietf.org/doc/statement-iesg-statement-on-clarifying-the-use-of-bcp-14-key-words/ for more information.

### Section 6

Why not a "MUST" in `Decapsulated frames with the inner VLAN ID SHOULD be discarded unless configured explicitly to be passed on to the non-VXLAN interface.` ?

Also, is this just examples ? Then, BCP14 terms should not be used.

### Section 6.1

The guidance about inner VLAN tags is important and must appear *before* VXLAN deployment scenarios.

More important, the implementers and operators are lost in the absence of guidance about the 3 "SHOULD".

[Ballot comment]

## COMMENTS (non-blocking)

### Why informational and not proposed standard ?

With the wide deployment of VXLAN, I wonder why the NVO3 WG did not prefer to have a proposed standard intended publication status? Alas, the shepherd's write-up is silent on this point, i.e., a reply will be greatly appreciated.

### Section 1

Should there be an informative reference to 802.1Q (if not mistaken) for `The current VLAN limit of 4094` ?

Should there be an informative reference to 802.1D (if not mistaken) for `Spanning Tree Protocol (STP)` ? (like in section 3.1)

### Section 3.1

Suggest to also expand "SPB" in the section even if introduced in terminology (SPT is expanded earlier in the text even if well known).

Unsure about the link between SPT and VLAN count in `Moreover, due to STP, several data centers limit the number of VLANs that could be used.` or is it only to reduce the amount of SPT computations ? Either explain the link or remove `due to STP` as there could be other reasons.

### Section 4

`16 M` is rather cryptic, either use the correct number or use "more than 16 millions".

Who is the "you" in `you could have overlapping MAC addresses` ? This is ambiguous (and IMHO too personal in a specification), suggest rephrasing or using the passive voice.

`see Figure 1` but the Figure 1 is really far from this text. At least, add in which section Figure 1 is located (as done in section 4.1) More important, Figure 1 does really explain `the VM never sees it` as it is a packet format only.

### Section 4.2

Amazing to read `the VM sends out an Address Resolution Protocol (ARP) broadcast frame` in an IETF document in 2026... Please use IPv6 Neighbour Soliciation.

Who is the "we" in `we need to have a mapping` ? The authors ? The WG ? The IETF community ? Please avoid ambiguities. Possibly also in other places.

### Section 6

About Figure 4, about `Decapsulated frames with the inner VLAN ID SHOULD be discarded unless configured explicitly to be passed on to the non-VXLAN interface.` (also note the DISCUSS issue), I completely fail to understand the reasoning behind it as VXLAN could be used to transport VLAN-tagged frames. Only later section 6.1 explains why.

### Section 8.2

Should the newly created registry be more described ? E.g., naming the columns/fields ?

### Section 9.2

You cannot have both "draft" in the title and "Std" in the reference in `Draft Standard for Local and Metropolitan Area Networks/ Media Access Control (MAC) Bridges", IEEE Std 802.1D-2004, 2004` ;-)

Isn't amendment `P802.1aq-2012` now included in a IEEE Std 802.1Q as clause 27 ?

## NITS (non-blocking / cosmetic)

### Use of SVG graphics

To make a much nicer HTML rendering, suggest using the aasvg tool to generate SVG graphics. It is worth a try especially if the I-D uses the Kramdown file format ;-)

IANA Note:

There are still issues with this document's IANA Considerations section:

1) Section 8.1 mentions that a previously-assigned port is in use, but doesn't make it clear that this document is acting on the registration. If this document should be the new reference, adding a line like this would be fine: IANA will list the IESG, the IETF Chair, and this document in the registration's "Assignee," "Contact," and "Reference" fields, respectively.

2) Section 8.2 assigns a registration procedure, but doesn't make any values available for assignment. If values 0-3 and 5-15 are all meant to be assignable via IETF Review, they should be listed as "Unassigned" rather than "Reserved." See RFC 8126, Section 6.

[Ballot comment]
# IESG review of draft-ietf-nvo3-rfc7348bis-05

CC @MikeBishop

## Comments

### Section 8.1, paragraph 2

Shouldn't this document request IANA to update the Reference, Assignee,
and Contact fields for that registration? For IETF documents, that would
normally point to the RFC and the IETF/IESG.

### Section 8.2, paragraph 5

I agree with Ketan, these seem more like Unassigned than Reserved.

## Nits

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.

### Grammar/style

#### Section 3.1, paragraph 1
```
mpatible with a Layer 2 model for inter- VM communication. A key characteris
                                  ^^^^^^^^^
```
This word seems to be formatted incorrectly. Consider fixing the spacing or
removing the hyphen completely.

## Notes

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. Review generated by the [`ietf-reviewtool`][IRT].

[ICMF]: https://github.com/mnot/ietf-comments/blob/main/format.md
[ICT]: https://github.com/mnot/ietf-comments
[IRT]: https://github.com/larseggert/ietf-reviewtool

[Ballot discuss]
Hi Mallik, Dinesh, Larry, Sridhar, and Ali,

Thank you for the effort put into this document.

I considered the limited scope set for this bis and adjusted my review accordingly:

# Configurable port number

CURRENT:
      *  Destination Port: IANA has assigned the value 4789 for the
        VXLAN UDP port, and this value MUST be used as the destination
        UDP port.

RFC7348 used to have a provision for configuring that port. Such capability is still supported by implementation.

Is there any reason why this configuration is disabled here?


# Is there any missing IANA action in Section 8.1?

Either this section is to be deleted (as it contains no action) or update it to request IANA to update the vxlan entry to also include the reference to this document.

# Reserved vs. Unassigned

CURRENT:
  *  Bits 0-3 - Reserved

  *  Bit 4 - Instance ID (I bit)

  *  Bit 5-15 - Reserved

RFC8126 says:
      Reserved:  Not assigned and not available for assignment.
            Reserved values are held for special uses, such as to extend
            the namespace when it becomes exhausted.  "Reserved" is also
            sometimes used to designate values that had been assigned
            but are no longer in use, keeping them set aside as long as
            other unassigned values are available.  Note that this is
            distinctly different from "Unassigned".

I think “reserved” should be changed to “unassigned” as these are open for assignment.

As I’m there, please consider making this change:

OLD:
      *  VXLAN Flags (16 bits): where Bit 4 is I flag and MUST be set to
        1 for a valid VXLAN Network ID (VNI).  The remaining reserved
        bits in this flag field MUST be set to 0 by the sender and
        ignored by the receiver.

NEW:
      *  VXLAN Flags (16 bits): where Bit 4 is I flag and MUST be set to
        1 for a valid VXLAN Network ID (VNI).  The remaining unassigned
        bits in this flag field MUST be set to 0 by the sender and
        ignored by the receiver.

# Normative references

CURRENT:
  Other techniques
  like Path MTU discovery (see [RFC1191] and [RFC8201]) MAY be used to
  address this requirement as well.

Although these are cited as optional, these two RFCs are normative per https://datatracker.ietf.org/doc/statement-iesg-iesg-statement-normative-and-informative-references-20060419/. Please double check.

As I’m there, please check that all required references are cited. For example, rfc6935 for tunneling and checksum.

[Ballot comment]
# Backward compatibility claim

CURRENT:
  The format and processing described
  here are fully compatible with those in RFC7348.

The change in the flags/reserved fields are OK as an implementation need to be upgraded anyway to associate a meaning with a new flag. Stealing more flag bits is still compatible. Ca,n,

RFC7347:

|R|R|R|R|I|R|R|R|            Reserved                          |

Bis:

|      VXLAN Flags            |          Reserved            |

Can we please include an “operational considerations” section that covers the backward compatibility vs 7348?

# Boilerplate

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

Please update to use the latest version.

# Registry Structure

CURRENT:
  This document creates a two-octet registry called "VXLAN Flags".
  There are sixteen flag bits at the beginning of the VXLAN header and
  IANA is asked to register the following bits in this two-octet
  registry.

I would define a VXLAN registry group, and then anchor the “VXLAN Flags” registry under that group. This would help structure any future VXLAN registry needs that may arise in the future.

# Registry Structure

CURRENT:
  *  Bits 0-3 - Reserved

  *  Bit 4 - Instance ID (I bit)

  *  Bit 5-15 - Reserved

## It would be useful to have a reference column

## The bits are more “Bit Position”

Cheers,
Med

[Ballot discuss]
Thanks to the authors and the WG for their work on this document.

Bringing VXLAN base specification on the IETF stream is a step that I
support wholeheartedly.

Please note that my review focusses on the delta with RFC 7348 base
(https://author-tools.ietf.org/iddiff?url1=rfc7348&url2=draft-ietf-nvo3-rfc7348bis-05&difftype=--html)
and this document could do a better job of capturing those changes for
everyone's benefit.

I have one point to discuss that is related to the VXLAN flags registry
(one of the key purpose of this effort).

Section 8.2

840  This document creates a two-octet registry called "VXLAN Flags".
841  There are sixteen flag bits at the beginning of the VXLAN header and
842  IANA is asked to register the following bits in this two-octet
843  registry.

845  *  Bits 0-3 - Reserved

847  *  Bit 4 - Instance ID (I bit)

849  *  Bit 5-15 - Reserved

851  New values are assigned by IETF Review [RFC8126].

RFC 8126 distinguishes Unassigned values, which remain available, from
Reserved values, which are not available for assignment. Section 8.2
labels all flag bits (baring I) Reserved and then supplies an assignment
policy for “new values.”

Suggested resolution:
Divide the initial space deliberately: mark bits that are available for
future allocation as Unassigned, retain Reserved only for bits that must
not be allocated, and explain any such reservation. The initial registry
should also identify its parent registry group (I suggest to call it
VXLAN Parameters) and this is separate from the "VXLAN Flags" which should
be this specific registry to allow for future/other registries under VXLAN.
The for this registry table identify the columns: Bit, Name, and Reference.
Explicitly set the reference to this document for the initial allocations.
Keep IETF Review as the policy. Change controller to IETF/IESG.

[Ballot comment]
Please find below some comments on this document inline in the idnits output of v05.
Look out for the  tag at the end to ensure you are seeing the full review.

30  here are fully compatible with those in RFC7348.


Change RFC7348 to RFC 7348.

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

Please fix the BCP 14 template

437  VXLAN Header:  This is an 8-octet field that has:

439      *  VXLAN Flags (16 bits): where Bit 4 is I flag and MUST be set to
440        1 for a valid VXLAN Network ID (VNI).  The remaining reserved
441        bits in this flag field MUST be set to 0 by the sender and
442        ignored by the receiver.

444      *  VXLAN Segment ID/VXLAN Network Identifier (VNI): this is a
445        24-bit value used to designate the individual VXLAN overlay
446        network on which the communicating VMs are situated.  VMs in
447        different VXLAN overlay networks cannot communicate with each
448        other.

450      *  Reserved fields - 16 bits and 8 bits.  These two reserved
451        fields MUST be set to 0 by the sender and ignored by the
452        receiver.

RFC 7348 describes an 8-bit Flags field followed by a 24-bit
Reserved field. This bis reclassifies the first eight bits of that
Reserved field as part of a new 16-bit VXLAN Flags field, leaving a
shorter 16-bit reserved field. The bit positions and packet length
do not change, but the semantic reorganization is a deliberate protocol
change that enables future flag allocation. The document does not
identify or justify it despite claiming full compatibility. It also
calls both the remaining 16-bit field and final 8-bit field simply
Reserved, making cross-reference and future allocation discussions
ambiguous.

Suggestions:
Add explanatory text such as: To establish an IANA-managed extension point,
this document reclassifies the first eight bits of RFC 7348's 24-bit Reserved
field as additional flag bits. The result is a 16-bit VXLAN Flags field
followed by a 16-bit Reserved-1 field. This reclassification does not change
any bit position or the size of the VXLAN header. Bits not assigned by the
VXLAN Flags registry continue to be transmitted as zero and ignored on receipt.

Call the 16-bit field Reserved-1 and the final 8-bit field Reserved-2
consistently in the prose and in both IPv4 and IPv6 figures. This will allow
for future extensions in an unambiguous manner.

454  Outer UDP Header:  This is the outer UDP header with a source port
455      provided by the VTEP and the destination port being a well-known
456      UDP port.

458      *  Destination Port: IANA has assigned the value 4789 for the
459        VXLAN UDP port, and this value MUST be used as the destination
460        UDP port.

RFC 7348 says that 4789 SHOULD be used by default, notes that
early implementations used other ports, and says the destination port
SHOULD be configurable. Port 4789 is now widely implemented and deployed,
so tightening that language is reasonable. The issue is that the bis silently
changes the requirement while claiming that format and processing are fully
compatible. An implementation retaining a historical default becomes
nonconforming, and tunnel classification, ACLs, and operational interworking
can depend on the selected destination port. I won't go into implementations
here.

Suggestion:
Keep the MUST if that reflects the WG's intended change, but state the delta
and rationale explicitly and qualify the compatibility claim. Perhaps:

RFC 7348 recommended UDP port 4789 by default while allowing a configurable
destination port for interoperability with early deployments. This document
requires the IANA-assigned port 4789 because that port is now widely
implemented and deployed. This is a deliberate tightening of RFC 7348;
deployments using a historical alternate port need to migrate or configure
port 4789 to conform to this specification. Apart from the changes identified
in this document, the VXLAN wire format and processing remain compatible with
RFC 7348.

471      *  UDP Checksum: It SHOULD be transmitted as zero.  When a packet
472        is received with a UDP checksum of zero, it MUST be accepted
473        for decapsulation.  Optionally, if the encapsulating end point
474        includes a non-zero UDP checksum, it MUST be correctly
475        calculated across the entire packet including the IP header,
476        UDP header, VXLAN header, and encapsulated MAC frame.  When a
477        decapsulating end point receives a packet with a non-zero
478        checksum, it MAY choose to verify the checksum value.  If it
479        chooses to perform such verification, and the verification
480        fails, the packet MUST be dropped.  If the decapsulating
481        destination chooses not to perform the verification, or
482        performs it successfully, the packet MUST be accepted for
483        decapsulation.

The checksum rules are stated once and therefore cover both outer
address families. VXLAN does seem to qualify for the constrained tunnel
exception in RFC 6935/RFC 6936 when used on a specifically enabled port
in a traffic-managed controlled environment. Since there is the use of
SHOULD, I believe there is deployment evidence for both choices. Without
getting into implementations, this needs to be clarified.

And then for IPv6 VXLAN deployment, the RFC 6936 requirements need to be
touched upon.

The sentence saying that a non-zero checksum is calculated
“including the IP header” also needs correction: the UDP checksum uses an
IP pseudo-header, not the complete IP header. This is a grave enough
error that warrants correction - some may deem it worthy of a DISCUSS.

Suggestion:
Separate the IPv4 and IPv6 rules and add RFC 6936 as a normative reference.
The following text preserves zero-checksum deployments without treating the
exception as universal (please feel free to wordsmith):

For IPv4, the UDP checksum SHOULD be transmitted as zero. For IPv6, a VTEP
SHOULD use the zero-checksum mode defined by [RFC6935] and [RFC6936]. This
mode is appropriate for most VXLAN deployments in traffic-managed controlled
environments where avoiding a full-packet checksum is operationally necessary
and the operator accepts the residual risk of undetected corruption. An
implementation MAY provide configuration for operations using IPv6 non-zero
checksum in deployments where that is necessary per [RFC6936].

Also replace “including the IP header” with “including the IP pseudo-header,”
and cite RFC 8200 normatively for ordinary IPv6 UDP processing.
This wording is somewhat close to the deployed-compatible exception
structure in GENEVE RFC 8926 and (I believe) VXLAN deployments; please
correct me if I am wrong.

525  |  Time to Live |Protocl=17(UDP)|  Header Checksum            |


This is a verified RFC 7348 Erratum 4990
(https://www.rfc-editor.org/errata/eid4990). To keep the diagram compact,
suggest to change the field to Proto = 17 (UDP) and add or update the
accompanying description to say that Proto is the IPv4 Protocol field
and is set to 17 for UDP. This incorporates the verified correction.


832  8.1.  UDP Port

834  A well-known UDP port (4789) has been assigned by the IANA in the
835  Service Name and Transport Protocol Port Number Registry for VXLAN.
836  See Section 5 for discussion of the port number.

Port 4789 is in the User/Registered Port range, not the
System/Well-Known Port range defined by RFC 6335. More importantly for an
obsoleting RFC, the current IANA service-name registry entry
(https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=4789)
cites RFC 7348, but Section 8.1 does not explicitly ask IANA to update
that reference.

Suggestion:
Replace “well-known” with “registered” (or simply “the VXLAN UDP
destination port”), and add an explicit instruction: “IANA is requested
to update the reference for the vxlan UDP port 4789 entry from RFC 7348
to this document.”

IESG/Authors/WG Chairs:

IANA has completed its review of draft-ietf-nvo3-rfc7348bis-04. If any part of this review is inaccurate, please let us know.

We have questions about each of the actions requested in the IANA Considerations section of this document.

The IANA understands that, upon approval of this document, there are two actions which we must complete.

First, in the Service Name and Transport Protocol Port Number Registry, UDP port number 4789 has been previously registered to Virtual eXtensible Local Area Network (VXLAN).

IANA Question --> Should [ RFC-to-be ] be added to, or replace, the existing reference [RFC7348] for this port number?

Second, a new registry is to be created called the VXLAN Flags registry.

IANA Question --> Where should this new registry be located? Should it be added to an existing registry group?

The registry will be managed via IANA Review as defined in [RFC8126]. There are initial registrations in the new registry as follows:

Bits 0-3 - Reserved
Bit 4 - Instance ID (I bit)
Bit 5-15 - Reserved

Each of these will have a reference of [ RFC-to-be ].

IANA Question --> IANA notes that, in Section 8.2 of the current document, there is the following request:

Furthermore, there are two additional reserved fields in the VXLAN header, a 16-bit reserved field that follows the VXLAN Flags and a 8-bit reserved field in the second word at the end of the VXLAN header.

Bit 16-31 in the 1st word - Reserved
Bits 24-31 in the 2nd Word - Reserved

Are these intended as a separate registry or sub-registry of the new VXLAN Registry? Could the authors expand Section 8.2 of the current draft to give more specific instructions to IANA about how these bits in the 1st and 2nd word of the VXLAN header should be represented in the registry?

We understand that these two actions are the only ones required to be completed upon approval of this document.

NOTE: The actions requested in this document will not be completed until the document has been approved for publication as an RFC. This message is meant only to confirm the list of actions that will be performed.

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 2026-08-09):

From: The IESG
To: IETF-Announce
CC: draft-ietf-nvo3-rfc7348bis@ietf.org, gunter@vandevelde.cc, matthew.bocci@nokia.com, nvo3-chairs@ietf.org, nvo3@ietf.org
Reply-To: last-call@ietf.org
Sender:
Subject: Last Call:  (Virtual eXtensible Local Area Network (VXLAN): A Framework for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks) to Informational RFC


The IESG has received a request from the Network Virtualization Overlays WG
(nvo3) to consider the following document: - 'Virtual eXtensible Local Area
Network (VXLAN): A Framework for
  Overlaying Virtualized Layer 2 Networks over Layer 3 Networks'
  as Informational RFC

The IESG plans to make a decision in the next few weeks, and solicits final
comments on this action. Please send substantive comments to the
last-call@ietf.org mailing lists by 2026-08-09. 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 specifies Virtual eXtensible Local Area Network
  (VXLAN), which is used to address the need for overlay networks
  within virtualized data centers accommodating multiple tenants.  The
  scheme and the related protocols can be used in networks for cloud
  service providers and enterprise data centers.  This document
  obsoletes RFC 7348, which documented the deployed VXLAN protocol for
  the benefit of the Internet community, and moves the VXLAN
  specification to the IETF document stream, allowing for the creation
  of extensions to VXLAN that require additions to the VXLAN header and
  their registration with IANA.  The format and processing described
  here are fully compatible with those in RFC7348.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-nvo3-rfc7348bis/



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

# Document Shepherd Write-Up for Group Documents

## 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 document achieved broad working group consensus. Multiple working group
participants reviewed the document during its development and Working Group
Last Call, and comments received during WGLC were addressed by the authors.
Support for publication was expressed by participants representing multiple
vendors and operators. The consensus was not limited to a small set of
contributors.


2. Was there controversy about particular points, or were there decisions
where the consensus was particularly rough?

There were no significant controversies during working group review. Comments
received during review focused on clarification, editorial improvements, and
ensuring consistency with current deployment and implementation practices.
Consensus on the final document was straightforward and did not require any
particularly rough consensus calls.

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 participant has threatened an appeal or expressed extreme discontent with
the document or with the working group process.

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][3] recommends) or
elsewhere (where)?

The document updates an existing specification that has been widely
implemented and deployed. Implementations of the underlying technology exist
from multiple vendors and in open-source software.

RFC 7348 was originally published as an Informational RFC through the
Independent Stream, documenting an already-deployed industry protocol.
Since then, VXLAN has become a foundational encapsulation technology and
subsequent IETF work has identified a need to define extensions that require
assignments within the VXLAN header. The main purpose of this document is to
obsolete RFC 7348, move the VXLAN specification to the IETF stream, establish
the necessary IANA registries for VXLAN header fields, and provide an
authoritative specification under IETF change control. The document preserves
wire-format and behavioral compatibility with RFC 7348 and is not intended to
change deployed VXLAN implementations.

Note that the process of republishing RFC7348 on the IETF stream was done in
collaboration with and with the agreement of the original RFC authors, as
well as the area directors responsible for NVO3 at the time,

## 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.

The document primarily concerns technology within the chartered scope of the
NVO3 working group. VXLAN is widely used as a data plane in Ethernet VPNs
(EVPN) defined by the BESS working group. One of the main motivations of
RFC7348bis is to allow VXLAN to carry an EVPN Group Policy ID, the control
plane extensions being defined in BESS. The work on RSC7348bis was
coordinated with the BESS working group.


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.

The document does not contain MIB modules, YANG modules, media type
registrations, URI registrations, or other constructs requiring formal expert
review. Therefore, no such reviews were 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][4] 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][5]?

This document does not contain any YANG modules.


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.

The document does not contain content written in a formal language such as
YANG, MIB, XML schema, BNF, CDDL, or similar constructs requiring automated
validation.


## 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?

I have reviewed the document in detail and provided comments to the authors,
which were fixed. I believe that it is needed, clearly written, technically
sound, complete, and ready for publication.

10. Several IETF Areas have assembled [lists of common issues that their
reviewers encounter][6]. For which areas have such issues been identified and
addressed? For which does this still need to happen in subsequent reviews?

No outstanding issues identified.

11. What type of RFC publication is being requested on the IETF stream ([Best
Current Practice][12], [Proposed Standard, Internet Standard][13],
[Informational, Experimental or Historic][14])? Why is this the proper type
of RFC? Do all Datatracker state attributes correctly reflect this intent?

The requested publication type is Informational. This is appropriate as the
document describes an existing, widely deployed protocol that was originally
developed outside of the IETF, while allowing the establishment the necessary
IANA registries for VXLAN header fields.

12. Have reasonable efforts been made to remind all authors of the
intellectual property rights (IPR) disclosure obligations described in [BCP
79][7]? 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.

An IPR poll was conducted on the NVO3 list. The working group chairs reminded
the authors of their obligations under BCP 79. There are no IPR disclosures
against either this document or the original RFC.

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 authors and editors have confirmed their willingness to be listed in the
document and are aware of the responsibilities associated with authorship and
editorship.

14. Document any remaining I-D nits in this document. Simply running the
[idnits tool][8] is not enough; please review the ["Content Guidelines" on
authors.ietf.org][15]. (Also note that the current idnits tool generates some
incorrect warnings; a rewrite is underway.)

I have reviewed the document, including idnits output and the IETF content
guidelines. No significant issues remain.


15. Should any informative references be normative or vice-versa? See the
[IESG Statement on Normative and Informative References][16].

The references are correctly classified as normative and informative. No
changes are believed necessary.


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

None. All references are to IETF RFCs.


17. Are there any normative downward references (see [RFC 3967][9] and [BCP
97][10]) that are not already listed in the [DOWNREF registry][17]? If so,
list them.

None. All references are to IETF RFCs.


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?

None. All references are to IETF RFCs.



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.

Publication of this document will obsolete RFC 7843. The Datatracker metadata
correctly reflects this relationship. T he title page, abstract, and
introduction identify the document's relationship to RFC 7843 and explain the
reasons for replacing it.


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][11]).

I have reviewed the IANA Considerations section and found it to be
consistent with the technical specification in the body of the document. The
document requests two IANA actions:

It records the use of the already assigned UDP destination port 4789 for
VXLAN in the Service Name and Transport Protocol Port Number Registry,
consistent with the VXLAN encapsulation described in Section 5.

It creates a new IANA registry named "VXLAN Flags" for the 16 flag bits in
the VXLAN header. The registry is initialized with:

Bits 0-3: Reserved Bit 4: Instance ID (I bit) Bits 5-15: Reserved

The document also identifies the additional reserved fields in the VXLAN
header (bits 16-31 of the first header word and bits 24-31 of the second
word) and specifies that reserved bits and fields MUST be set to zero by
senders and ignored by receivers. Future assignments from the VXLAN Flags
registry are to be made through the IETF Review policy defined in RFC 8126.



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.

The allocation process is by IETF review, and so no designated experts are required.


[1]: https://www.ietf.org/about/groups/iesg/ [2]:
https://www.rfc-editor.org/rfc/rfc4858.html [3]:
https://www.rfc-editor.org/rfc/rfc7942.html [4]:
https://wiki.ietf.org/group/ops/yang-review-tools [5]:
https://www.rfc-editor.org/rfc/rfc8342.html [6]:
https://wiki.ietf.org/group/iesg/ExpertTopics [7]:
https://www.rfc-editor.org/info/bcp79 [8]: https://www.ietf.org/tools/idnits/
[9]: https://www.rfc-editor.org/rfc/rfc3967.html [10]:
https://www.rfc-editor.org/info/bcp97 [11]:
https://www.rfc-editor.org/rfc/rfc8126.html [12]:
https://www.rfc-editor.org/rfc/rfc2026.html#section-5 [13]:
https://www.rfc-editor.org/rfc/rfc2026.html#section-4.1 [14]:
https://www.rfc-editor.org/rfc/rfc2026.html#section-4.2 [15]:
https://authors.ietf.org/en/content-guidelines-overview [16]:
https://www.ietf.org/about/groups/iesg/statements/normative-informative-
references/ [17]: https://datatracker.ietf.org/doc/downref/

# Document Shepherd Write-Up for Group Documents

## 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 document achieved broad working group consensus. Multiple working group
participants reviewed the document during its development and Working Group
Last Call, and comments received during WGLC were addressed by the authors.
Support for publication was expressed by participants representing multiple
vendors and operators. The consensus was not limited to a small set of
contributors.


2. Was there controversy about particular points, or were there decisions
where the consensus was particularly rough?

There were no significant controversies during working group review. Comments
received during review focused on clarification, editorial improvements, and
ensuring consistency with current deployment and implementation practices.
Consensus on the final document was straightforward and did not require any
particularly rough consensus calls.

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 participant has threatened an appeal or expressed extreme discontent with
the document or with the working group process.

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][3] recommends) or
elsewhere (where)?

The document updates an existing specification that has been widely
implemented and deployed. Implementations of the underlying technology exist
from multiple vendors and in open-source software.

RFC 7348 was originally published as an Informational RFC through the
Independent Stream, documenting an already-deployed industry protocol.
Since then, VXLAN has become a foundational encapsulation technology and
subsequent IETF work has identified a need to define extensions that require
assignments within the VXLAN header. The main purpose of this document is to
obsolete RFC 7348, move the VXLAN specification to the IETF stream, establish
the necessary IANA registries for VXLAN header fields, and provide an
authoritative specification under IETF change control. The document preserves
wire-format and behavioral compatibility with RFC 7348 and is not intended to
change deployed VXLAN implementations.

Note that the process of republishing RFC7348 on the IETF stream was done in
collaboration with and with the agreement of the original RFC authors, as
well as the area directors responsible for NVO3 at the time,

## 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.

The document primarily concerns technology within the chartered scope of the
NVO3 working group. VXLAN is widely used as a data plane in Ethernet VPNs
(EVPN) defined by the BESS working group. One of the main motivations of
RFC7348bis is to allow VXLAN to carry an EVPN Group Policy ID, the control
plane extensions being defined in BESS. The work on RSC7348bis was
coordinated with the BESS working group.


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.

The document does not contain MIB modules, YANG modules, media type
registrations, URI registrations, or other constructs requiring formal expert
review. Therefore, no such reviews were 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][4] 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][5]?

This document does not contain any YANG modules.


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.

The document does not contain content written in a formal language such as
YANG, MIB, XML schema, BNF, CDDL, or similar constructs requiring automated
validation.


## 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?

I have reviewed the document in detail and provided comments to the authors,
which were fixed. I believe that it is needed, clearly written, technically
sound, complete, and ready for publication.

10. Several IETF Areas have assembled [lists of common issues that their
reviewers encounter][6]. For which areas have such issues been identified and
addressed? For which does this still need to happen in subsequent reviews?

No outstanding issues identified.

11. What type of RFC publication is being requested on the IETF stream ([Best
Current Practice][12], [Proposed Standard, Internet Standard][13],
[Informational, Experimental or Historic][14])? Why is this the proper type
of RFC? Do all Datatracker state attributes correctly reflect this intent?

The requested publication type is Informational. This is appropriate as the
document describes an existing, widely deployed protocol that was originally
developed outside of the IETF, while allowing the establishment the necessary
IANA registries for VXLAN header fields.

12. Have reasonable efforts been made to remind all authors of the
intellectual property rights (IPR) disclosure obligations described in [BCP
79][7]? 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.

An IPR poll was conducted on the NVO3 list. The working group chairs reminded
the authors of their obligations under BCP 79. There are no IPR disclosures
against either this document or the original RFC.

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 authors and editors have confirmed their willingness to be listed in the
document and are aware of the responsibilities associated with authorship and
editorship.

14. Document any remaining I-D nits in this document. Simply running the
[idnits tool][8] is not enough; please review the ["Content Guidelines" on
authors.ietf.org][15]. (Also note that the current idnits tool generates some
incorrect warnings; a rewrite is underway.)

I have reviewed the document, including idnits output and the IETF content
guidelines. No significant issues remain.


15. Should any informative references be normative or vice-versa? See the
[IESG Statement on Normative and Informative References][16].

The references are correctly classified as normative and informative. No
changes are believed necessary.


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

None. All references are to IETF RFCs.


17. Are there any normative downward references (see [RFC 3967][9] and [BCP
97][10]) that are not already listed in the [DOWNREF registry][17]? If so,
list them.

None. All references are to IETF RFCs.


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?

None. All references are to IETF RFCs.



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.

Publication of this document will obsolete RFC 7843. The Datatracker metadata
correctly reflects this relationship. T he title page, abstract, and
introduction identify the document's relationship to RFC 7843 and explain the
reasons for replacing it.


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][11]).

I have reviewed the IANA Considerations section and found it to be
consistent with the technical specification in the body of the document. The
document requests two IANA actions:

It records the use of the already assigned UDP destination port 4789 for
VXLAN in the Service Name and Transport Protocol Port Number Registry,
consistent with the VXLAN encapsulation described in Section 5.

It creates a new IANA registry named "VXLAN Flags" for the 16 flag bits in
the VXLAN header. The registry is initialized with:

Bits 0-3: Reserved Bit 4: Instance ID (I bit) Bits 5-15: Reserved

The document also identifies the additional reserved fields in the VXLAN
header (bits 16-31 of the first header word and bits 24-31 of the second
word) and specifies that reserved bits and fields MUST be set to zero by
senders and ignored by receivers. Future assignments from the VXLAN Flags
registry are to be made through the IETF Review policy defined in RFC 8126.



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.

The allocation process is by IETF review, and so no designated experts are required.


[1]: https://www.ietf.org/about/groups/iesg/ [2]:
https://www.rfc-editor.org/rfc/rfc4858.html [3]:
https://www.rfc-editor.org/rfc/rfc7942.html [4]:
https://wiki.ietf.org/group/ops/yang-review-tools [5]:
https://www.rfc-editor.org/rfc/rfc8342.html [6]:
https://wiki.ietf.org/group/iesg/ExpertTopics [7]:
https://www.rfc-editor.org/info/bcp79 [8]: https://www.ietf.org/tools/idnits/
[9]: https://www.rfc-editor.org/rfc/rfc3967.html [10]:
https://www.rfc-editor.org/info/bcp97 [11]:
https://www.rfc-editor.org/rfc/rfc8126.html [12]:
https://www.rfc-editor.org/rfc/rfc2026.html#section-5 [13]:
https://www.rfc-editor.org/rfc/rfc2026.html#section-4.1 [14]:
https://www.rfc-editor.org/rfc/rfc2026.html#section-4.2 [15]:
https://authors.ietf.org/en/content-guidelines-overview [16]:
https://www.ietf.org/about/groups/iesg/statements/normative-informative-
references/ [17]: https://datatracker.ietf.org/doc/downref/

# Document Shepherd Write-Up for Group Documents

## 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 document achieved broad working group consensus. Multiple working group
participants reviewed the document during its development and Working Group
Last Call, and comments received during WGLC were addressed by the authors.
Support for publication was expressed by participants representing multiple
vendors and operators. The consensus was not limited to a small set of
contributors.


2. Was there controversy about particular points, or were there decisions
where the consensus was particularly rough?

There were no significant controversies during working group review. Comments
received during review focused on clarification, editorial improvements, and
ensuring consistency with current deployment and implementation practices.
Consensus on the final document was straightforward and did not require any
particularly rough consensus calls.

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 participant has threatened an appeal or expressed extreme discontent with
the document or with the working group process.

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][3] recommends) or
elsewhere (where)?

The document updates an existing specification that has been widely
implemented and deployed. Implementations of the underlying technology exist
from multiple vendors and in open-source software.

RFC 7348 was originally published as an Informational RFC through the
Independent Stream by the documenting an already-deployed industry protocol.
Since then, VXLAN has become a foundational encapsulation technology and
subsequent IETF work has identified a need to define extensions that require
assignments within the VXLAN header. The main purpose of this document is to
obsolete RFC 7348, move the VXLAN specification to the IETF stream, establish
the necessary IANA registries for VXLAN header fields, and provide an
authoritative specification under IETF change control. The document preserves
wire-format and behavioral compatibility with RFC 7348 and is not intended to
change deployed VXLAN implementations.

Note that the process of republishing RFC7348 on the IETF stream was done in
collaboration with and with the agreement of the original RFC authors, as
well as the area directors responsible for NVO3 at the time,

## 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.

The document primarily concerns technology within the chartered scope of the
NVO3 working group. VXLAN is widely used as a data plane in Ethernet VPNs
(EVPN) defined by the BESS working group. One of the main motivations of
RFC7348bis is to allow VXLAN to carry an EVPN Group Policy ID, the control
plane extensions being defined in BESS. The work on RSC7348bis was
coordinated with the BESS working group.


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.

The document does not contain MIB modules, YANG modules, media type
registrations, URI registrations, or other constructs requiring formal expert
review. Therefore, no such reviews were 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][4] 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][5]?

This document does not contain any YANG modules.


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.

The document does not contain content written in a formal language such as
YANG, MIB, XML schema, BNF, CDDL, or similar constructs requiring automated
validation.


## 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?

I have reviewed the document in detail and provided comments to the authors,
which were fixed. I believe that it is needed, clearly written, technically
sound, complete, and ready for publication.

10. Several IETF Areas have assembled [lists of common issues that their
reviewers encounter][6]. For which areas have such issues been identified and
addressed? For which does this still need to happen in subsequent reviews?

No outstanding issues identified.

11. What type of RFC publication is being requested on the IETF stream ([Best
Current Practice][12], [Proposed Standard, Internet Standard][13],
[Informational, Experimental or Historic][14])? Why is this the proper type
of RFC? Do all Datatracker state attributes correctly reflect this intent?

The requested publication type is Informational. This is appropriate as the
document describes an existing, widely deployed protocol that was originally
developed outside of the IETF, while allowing the establishment the necessary
IANA registries for VXLAN header fields.

12. Have reasonable efforts been made to remind all authors of the
intellectual property rights (IPR) disclosure obligations described in [BCP
79][7]? 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.

An IPR poll was conducted on the NVO3 list. The working group chairs reminded
the authors of their obligations under BCP 79. There are no IPR disclosures
against either this document or the original RFC.

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 authors and editors have confirmed their willingness to be listed in the
document and are aware of the responsibilities associated with authorship and
editorship.

14. Document any remaining I-D nits in this document. Simply running the
[idnits tool][8] is not enough; please review the ["Content Guidelines" on
authors.ietf.org][15]. (Also note that the current idnits tool generates some
incorrect warnings; a rewrite is underway.)

I have reviewed the document, including idnits output and the IETF content
guidelines. No significant issues remain.


15. Should any informative references be normative or vice-versa? See the
[IESG Statement on Normative and Informative References][16].

The references are correctly classified as normative and informative. No
changes are believed necessary.


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

None. All references are to IETF RFCs.


17. Are there any normative downward references (see [RFC 3967][9] and [BCP
97][10]) that are not already listed in the [DOWNREF registry][17]? If so,
list them.

None. All references are to IETF RFCs.


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?

None. All references are to IETF RFCs.



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.

Publication of this document will obsolete RFC 7843. The Datatracker metadata
correctly reflects this relationship. T he title page, abstract, and
introduction identify the document's relationship to RFC 7843 and explain the
reasons for replacing it.


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][11]).

I have reviewed the IANA Considerations section and found it to be
consistent with the technical specification in the body of the document. The
document requests two IANA actions:

It records the use of the already assigned UDP destination port 4789 for
VXLAN in the Service Name and Transport Protocol Port Number Registry,
consistent with the VXLAN encapsulation described in Section 5.

It creates a new IANA registry named "VXLAN Flags" for the 16 flag bits in
the VXLAN header. The registry is initialized with:

Bits 0-3: Reserved Bit 4: Instance ID (I bit) Bits 5-15: Reserved

The document also identifies the additional reserved fields in the VXLAN
header (bits 16-31 of the first header word and bits 24-31 of the second
word) and specifies that reserved bits and fields MUST be set to zero by
senders and ignored by receivers. Future assignments from the VXLAN Flags
registry are to be made through the IETF Review policy defined in RFC 8126.



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.

The allocation process is by IETF review, and so no designated experts are required.


[1]: https://www.ietf.org/about/groups/iesg/ [2]:
https://www.rfc-editor.org/rfc/rfc4858.html [3]:
https://www.rfc-editor.org/rfc/rfc7942.html [4]:
https://wiki.ietf.org/group/ops/yang-review-tools [5]:
https://www.rfc-editor.org/rfc/rfc8342.html [6]:
https://wiki.ietf.org/group/iesg/ExpertTopics [7]:
https://www.rfc-editor.org/info/bcp79 [8]: https://www.ietf.org/tools/idnits/
[9]: https://www.rfc-editor.org/rfc/rfc3967.html [10]:
https://www.rfc-editor.org/info/bcp97 [11]:
https://www.rfc-editor.org/rfc/rfc8126.html [12]:
https://www.rfc-editor.org/rfc/rfc2026.html#section-5 [13]:
https://www.rfc-editor.org/rfc/rfc2026.html#section-4.1 [14]:
https://www.rfc-editor.org/rfc/rfc2026.html#section-4.2 [15]:
https://authors.ietf.org/en/content-guidelines-overview [16]:
https://www.ietf.org/about/groups/iesg/statements/normative-informative-
references/ [17]: https://datatracker.ietf.org/doc/downref/