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Service Function Chaining
charter-ietf-sfc-00-03

The information below is for an older proposed charter
Document Proposed charter Service Function Chaining WG (sfc) Snapshot
Title Service Function Chaining
Last updated 2013-10-31
State Draft Charter
WG State BOF
IESG Responsible AD Andrew Alston
Charter edit AD Adrian Farrel
Send notices to jguichar@cisco.com, narten@us.ibm.com, adrian@olddog.co.uk, stbryant@cisco.com

charter-ietf-sfc-00-03

Networks, servers, storage technologies, and applications, have all
undergone significant change in recent years with the introduction of
virtualization, network overlays, and orchestration. Service delivery
is currently both a technical and organizational challenge that
involves significant modification to the network configuration.
Services are typically implemented by the ordered combination of a
number of service functions that are deployed at different points
within the network. Today, a common deployment model has service
functions physically inserted on the data forwarding path between
communicating peers. Going forward, however, there is a desire to
move to a different model, where service functions are not required to
reside on the default data path and traffic is instead steered through
services, wherever they are deployed.

For a given service, the abstracted view of the required service functions
and the order in which they are to be applied is called a Service Function
Chain (SFC). Since a given service function may be available on more
than one node within a network, a Service Function Chain is instantiated
via the selection of specific service function instances and the network
nodes on which they are provided, thereby forming a service topology:
this is called a Service Function Path. The service functions may be
applied at a specific layer within the network protocol stack (network
layer, application layer, etc.).

The Service Function Chaining (SFC) working group will develop new
approaches to service delivery and deployment. It will produce an
architecture for service function chaining that includes the necessary
protocols or protocol extensions to convey the service path and service
path information to nodes that implement service functions, as well as
mechanisms for steering traffic through service functions. The working
group will also examine what information needs to be gathered from the
network and service functions in support of service function chaining
and how that information may be made available to nodes that implement
the service functions.

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

1) Problem Statement: This document will provide a summary of the
problem space to be addressed by the WG including example high-
level use cases. Additionally, the WG will normalize nomenclature
and definitions for service function chaining.

2) Architecture: This document will provide a description of the
architectural building blocks and their relationships including
interconnection, placement of capabilities, management,
diagnostics, design analysis, and security models, as well as
requirements on the protocol mechanisms.

3) Generic Service Function Chaining Encapsulation: A document will
describe the single service-level data plane encapsulation format for
conveying the service function chain and the service function path,
and for communicating context information between nodes that
implement service functions. It is intended that the encapsulation
be agnostic to the layer at which it is applied and the service that is
being constructed. That is, the same encapsulation may be used on
a service function path realized at the network layer or at any other
layer, and the same encapsulation will apply for the construction of
service function paths regardless of the actual service.

4) Control Plane Mechanisms: A set of documents will be developed to
describe requirements and protocols necessary to convey information
to service function implementation points. Where possible, existing
IETF protocols will be used and extended. All protocol extensions
work should be carried out in the working groups responsible for the
protocols being modified in coordination with this working group, but
may be done in this working group after agreement with all the
relevant WG chairs and responsible ADs.

5) Manageability: This document will address the management of service
function chaining including relevant MIBs and YANG information and
data modules, and service function chaining diagnostics.