The Service Function Chaining (sfc) WG in the Routing Area of the IETF has
been rechartered. For additional information, please contact the Area
Directors or the WG Chairs.

Service Function Chaining (sfc)
Current status: Active WG

  Joel Halpern <>
  Jim Guichard <>

  Tal Mizrahi <>

Assigned Area Director:
  Alia Atlas <>

Routing Area Directors:
  Alia Atlas <>
  Alvaro Retana <>
  Deborah Brungard <>

Mailing list:
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Network operators frequently utilize service functions such as packet
filtering at firewalls, load-balancing and transactional proxies (for example
spam filters) in the delivery of services to end users. Delivery of these
types of services is undergoing significant change with the introduction of
virtualization, network overlays, and orchestration.

The SFC Working Group has developed an Architecture [RFC 7665] and the
Network Service Header [RFC 8300] for service function chaining.

The focus of the SFC working group moving forward is on aspects of the
architecture and/or protocol that need to be addressed to enable effective
deployment and usage of this work. In order to maintain focus, the working
group primarily produces and advances documents on four topics:

1) Metadata - Define the common type-length-value encoded metadata types with
Standards Track RFCs, and produce Informational RFCs to describe common
fixed-length (MD-1) metadata usages.

2) Security and Privacy - Mechanisms and guidance for securing metadata via
authentication, integrity protection, confidentiality, and/or data
minimization are not yet defined.  What can be effectively provided, for
which scenarios, and how those tools can be provided need to be determined
and the tools standardized.

3) OAM and Operations & Management - In order for operators to use these
tools in production networks, they need Operations, Administration, and
Maintenance tools, as well as management mechanisms.  This includes YANG
models, OAM frameworks, and specific OAM mechanisms to address operational

4) Transport Considerations - This will capture the expectations SFC places
on transport behavior, including dealing with issues such as congestion
indications and responses.  This should define how NSH works on standardized
transports that are expected to see widespread use.

Specifically, the SFC WG is chartered to deliver the following:

1. A Standards Track base set of the metadata MD-2 type codes within the
metadata class reserved for IETF usage, as specified in RFC 8300.

2. Related Metadata drafts that require more explanation than is reasonable
to include in the base MD-2 draft, including MD-1 descriptions and items done
once the base draft is complete.

3. YANG models for the management of SFC Components.

4. One or more security related Standards Track and / or Informational RFCs. 
At least one Standards Track security mechanism RFC is needed.

5. OAM Framework document to provide a common basis for OAM work.  This draft
will include guidance on how active, passive, and hybrid OAM are to be
supported if at all.

6. Specific OAM mechanism documents to provide the tools needed for
operational environments.

7. Transport Considerations RFC to cover the expectations SFC and NSH place
on transport, and the operational constraints transports used by NSH need to

The SFC WG may work on Informational applicability documents that show how
the technology, meta-data, and associated control-plane mechanisms can be
used in specific use-cases.  The SFC WG may work on Informational documents
that provide operational considerations.

The SFC WG will coordinate with BESS and PCE on the control-plane work
related to SFC.


  Apr 2014 - Consult with OPS area on possible SFC charter modifications for
  management and configuration of SFC components related to the support of
  Service Function Chaining

  Oct 2018 - Informational document defining the Operation, Administration
  and Maintenance (OAM) framework for SFC

  Dec 2018 - Submit to IESG Informational documents specifying the format of
  MD-type 1 metadata in DC and Broadband environments

  Dec 2018 - Submit to IESG Standards Track document specifying MD-type 2
  metadata formats

  Mar 2019 - YANG models for SFF and classifier

  Jul 2019 - Submit to IESG Informational document defining authentication,
  integrity protection, and confidentiality of SFC metadata

  Jul 2019 - Informational document defining transport considerations
  applicable to SFC

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