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 a framework 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.