Service Function Chaining

Document Charter Service Function Chaining WG (sfc)
Title Service Function Chaining
Last updated 2018-03-21
State Approved
WG State Active
IESG Responsible AD Martin Vigoureux
Charter Edit AD Martin Vigoureux
Send notices to (None)


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

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

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

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.