Skip to main content

Shepherd writeup

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 24 February 2012.

(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?

Proposed Standard.
It defines protocol extensions and procedures for BGP flowspec.
Yes the type is indicated in the title page header.

(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 Border Gateway Protocol Network Layer
   Reachability Information (BGP NLRI) encoding format that can be used
   to distribute traffic Flow Specifications.  This allows the routing
   system to propagate information regarding more specific components of
   the traffic aggregate defined by an IP destination prefix.

   It also specifies BGP Extended Community encoding formats, that can
   be used to propagate Traffic Filtering Actions along with the Flow
   Specification NLRI.  Those Traffic Filtering Actions encode actions a
   routing system can take if the packet matches the Flow Specification.

   Additionally, it defines two applications of that encoding format:
   one that can be used to automate inter-domain coordination of traffic
   filtering, such as what is required in order to mitigate
   (distributed) denial-of-service attacks, and a second application to
   provide traffic filtering in the context of a BGP/MPLS VPN service.
   Other applications (ie. centralized control of traffic in a SDN or
   NFV context) are also possible.  Other documents may specify Flow
   Specification extensions.

   The information is carried via BGP, thereby reusing protocol
   algorithms, operational experience, and administrative processes such
   as inter-provider peering agreements.

   This document obsoletes both RFC5575 and RFC7674.

Working Group Summary

  Was there anything in WG process that is worth noting? For
  example, was there controversy about particular points or
  were there decisions where the consensus was particularly

This draft includes numerous editorial changes which clarifies the unclear
specifications in RFC5575. There were questions/discussion about the precedence
order and combination of numeric operators, which have been resolved. There
were also some discussions about the validation of flowspec components, which
has been resolved as well. A later discussion is about whether and how existing
implementations are complied with the suggested behavior in this -bis document.
There were several options under consideration, and consensus was reached on
the option chosen in the current version .

After WGLC had completed and shortly after the document was submitted for
publication, an implementor brought forward a remaining bug in the
specification. The chair (John) thought it seriously enough to bring the
document back to the WG for further consideration. The bug was fixed and a
subsequent WGLC held to cover the change. The relevant mailing list thread is

Document Quality

  Are there existing implementations of the protocol?

Implementation report can be found at


Document Shepherd: Jie Dong
Responsible Area Director: Alvaro Retana

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

The document shepherd performed the review on:
1) Nits
2) Technical review
3) Implementation report
4) IPR check

The document shepherd think the document is ready for publication.

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


(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.

Nothing beyond the normal checks.

(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.


(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.

Robert Raszuk: no IPR

Danny McPherson: no IPR

Christoph Loibl: no IPR

Martin Bacher: no IPR

Susan Hares: no IPR

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

There are IPRs which were declared on RFC 5575, and should be inherited by this
-bis document. While in the datatracker, they are not linked to this document
automatically. Although a disclosure hasn’t been made to this document (yet),
the WG was made aware of the relevant disclosures, which were also called out
in IETF Last Call.

(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?

Solid consensus according to the review and discussion on the list.

(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.)


(11) Identify any ID nits the Document Shepherd has found in this
document. (See and the Internet-Drafts
Checklist). Boilerplate checks are not enough; this check needs to be

According to the ID nits check, there are 8 comments, which should be OK:

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

Not relevant for MIB Doctor, Media type, or URI.

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

All references have been identified as either normative or informative.

(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?


(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.


(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.

RFC 5575 and RFC 7674 will be obsoleted by this document.

They are listed on the title page header, and in the abstract.

(17) Describe the Document Shepherd's review of the IANA considerations
section, especially with regard to its consistency with the body of the
document. Confirm that all protocol extensions that the document makes
are associated with the appropriate reservations in IANA registries.
Confirm that any referenced IANA registries have been clearly
identified. Confirm that newly created IANA registries include a
detailed specification of the initial contents for the registry, that
allocations procedures for future registrations are defined, and a
reasonable name for the new registry has been suggested (see RFC 5226).

IANA has allocated the SAFI values 133, 134 for RFC5575, the reference needs to
be updated to this document.

IANA has created and maintains a registry entitled "Flow Spec Component Types"
for RFC5575, the reference needs to be updated to this document, and the
policies for this registry needs to be updated according to this document:
    0                     Reserved
    [1 .. 12]          Defined by this specification
    [13 .. 127]     Specification required
    [128 .. 255]   First Come First Served

IANA has allocated the following code points from the "BGP Transitive Extended
Community Types" registry for RFC 7674, the reference needs to be updated to
this document. 0x81  Generic Transitive Experimental Use Extended Community
Part 2 0x82  Generic Transitive Experimental Use Extended Community Part 3

IANA has allocated the following code points from the “Generic Transitive
Experimental Use Extended Community Sub-Types” registry for RFC 5575, the
reference of these code points needs to be updated to this document. 0x06  Flow
spec traffic-rate-bytes 0x07  Flow spec traffic-action (Use of the "Value"
field is defined in the "Traffic Action Fields" registry) 0x08  Flow spec
redirect AS-2octet format 0x09  Flow spec traffic-remarking

IANA is requested to allocate a new code point for “Flow spec
traffic-rate-packets” from the “Generic Transitive Experimental Use Extended
Community Sub-Types” registry.

IANA has created and maintains the registry entitled “Generic Transitive
Experimental Use Extended Community Part 2 Sub-Types” for RFC7674, the
reference needs to be updated to this document.

IANA has created and maintains the registry entitled “Generic Transitive
Experimental Use Extended Community Part 3 Sub-Types” for RFC7674, the
reference needs to be updated to this document.

IANA has created and maintains a registry entitled "Traffic Action Fields" for
RFC 5575, the reference needs to be updated to this document.

(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.


(19) Describe reviews and automated checks performed by the Document
Shepherd to validate sections of the document written in a formal
language, such as XML code, BNF rules, MIB definitions, etc.

No review of automated checks required.