SFC

A set of requirements for active Operations, Administration, and Maintenance (OAM) for Service Function Chaining (SFC) in a network is presented in this document. Based on these requirements, an encapsulation of active OAM messages in SFC and a mechanism to detect and localize defects are described.

This document describes the integration of the Network Service Header (NSH) and Segment Routing (SR), as well as encapsulation details, to efficiently support Service Function Chaining (SFC) while maintaining separation of the service and transport planes as originally intended by the SFC architecture.

Combining these technologies allows SR to be used for steering packets between Service Function Forwarders (SFFs) along a given Service Function Path (SFP), whereas the NSH is responsible for maintaining the integrity of the service plane, the SFC instance context, and any associated metadata.

This integration demonstrates that the NSH and SR can work cooperatively and provide a network operator with the flexibility to use whichever transport technology makes sense in specific areas of their network infrastructure while still maintaining an end-to-end service plane using the NSH.

In situ Operations, Administration, and Maintenance (IOAM) is used for recording and collecting operational and telemetry information while the packet traverses a path between two points in the network. This document outlines how IOAM-Data-Fields are encapsulated with the Network Service Header (NSH).

This document clarifies an ambiguity in the Network Service Header (NSH) specification related to the handling of O bit. In particular, this document clarifies the meaning of "OAM packet".

This document updates RFC 8300.

Service Function Chaining (SFC) uses the Network Service Header (NSH) (RFC 8300) to steer and provide context metadata (MD) with each packet. Such metadata can be of various types, including MD Type 2, consisting of Variable-Length Context Headers. This document specifies several such Context Headers that can be used within a Service Function Path (SFP).

The Network Service Header (NSH) specification defines two possible methods of including metadata (MD): MD Type 0x1 and MD Type 0x2. MD Type 0x1 uses a fixed-length Context Header. The allocation of this Context Header, i.e., its structure and semantics, has not been standardized. This memo defines the Timestamp Context Header, which is an NSH fixed-length Context Header that incorporates the packet's timestamp, a sequence number, and a source interface identifier.

Although the definition of the Context Header presented in this document has not been standardized by the IETF, it has been implemented in silicon by several manufacturers and is published here to facilitate interoperability.

This specification presents an optional method to add integrity protection directly to the Network Service Header (NSH) used for Service Function Chaining (SFC). Also, this specification allows for the encryption of sensitive metadata (MD) that is carried in the NSH.

This document describes the use of BGP as a control plane for networks that support service function chaining. The document introduces a new BGP address family called the "Service Function Chain (SFC) Address Family Identifier / Subsequent Address Family Identifier" (SFC AFI/SAFI) with two Route Types. One Route Type is originated by a node to advertise that it hosts a particular instance of a specified service function. This Route Type also provides "instructions" on how to send a packet to the hosting node in a way that indicates that the service function has to be applied to the packet. The other Route Type is used by a controller to advertise the paths of "chains" of service functions and give a unique designator to each such path so that they can be used in conjunction with the Network Service Header (NSH) defined in RFC 8300.

This document adopts the service function chaining architecture described in RFC 7665.

This document defines the Subscriber and Performance Policy Identifier Context Headers. These Variable-Length Context Headers can be carried in the Network Service Header (NSH) and are used to inform Service Functions (SFs) of subscriber- and performance-related information for the sake of policy enforcement and appropriate Service Function Chaining (SFC) operations. The structure of each Context Header and their use and processing by NSH-aware nodes are described.

This document provides a reference framework for Operations, Administration, and Maintenance (OAM) for Service Function Chaining (SFC).

Adoption of cloud and fog technology allows operators to deploy a single "Service Function" (SF) to multiple "execution locations". The decision to steer traffic to a specific location may change frequently based on load, proximity, etc. Under the current Service Function Chaining (SFC) framework, steering traffic dynamically to the different execution endpoints requires a specific "rechaining", i.e., a change in the service function path reflecting the different IP endpoints to be used for the new execution points. This procedure may be complex and take time. In order to simplify rechaining and reduce the time to complete the procedure, we discuss separating the logical Service Function Path (SFP) from the specific execution endpoints. This can be done by identifying the SFs using a name rather than a routable IP endpoint (or Layer 2 address). This document describes the necessary extensions, additional functions, and protocol details in the Service Function Forwarder (SFF) to handle name-based relationships.

This document presents InterDigital's approach to name-based SFC. It does not represent IETF consensus and is presented here so that the SFC community may benefit from considering this mechanism and the possibility of its use in the edge data centers.

This document describes how Service Function Chaining (SFC) can be achieved in an MPLS network by means of a logical representation of the Network Service Header (NSH) in an MPLS label stack. That is, the NSH is not used, but the fields of the NSH are mapped to fields in the MPLS label stack. This approach does not deprecate or replace the NSH, but it acknowledges that there may be a need for an interim deployment of SFC functionality in brownfield networks.

This document describes how to use a Service Function Forwarder (SFF) Label (similar to a pseudowire label or VPN label) to indicate the presence of a Service Function Chaining (SFC) Network Service Header (NSH) between an MPLS label stack and the packet original packet/ frame. This allows SFC packets using the NSH to be forwarded between SFFs over an MPLS network, and to select one of multiple SFFs in the destination MPLS node.

This document describes methods of carrying Key Performance Indicators (KPIs) using the Network Service Header (NSH). These methods may be used, for example, to monitor latency and QoS marking to identify problems on some links or service functions.

Hierarchical Service Function Chaining (hSFC) is a network architecture allowing an organization to decompose a large-scale network into multiple domains of administration.

The goals of hSFC are to make a large-scale network easier to design, simpler to control, and supportive of independent functional groups within large network operators.

This document describes a network that supports Service Function Chaining (SFC) using the Network Service Header (NSH) with no payload data and carrying only metadata. This is achieved by defining a new NSH "Next Protocol" type value of "None".

This document illustrates some of the functions that may be achieved or enhanced by this mechanism, but it does not provide an exhaustive list of use cases, nor is it intended to be definitive about the functions it describes. It is expected that other documents will describe specific use cases in more detail and will define the protocol mechanics for each use case.

This document describes a Network Service Header (NSH) imposed on packets or frames to realize Service Function Paths (SFPs). The NSH also provides a mechanism for metadata exchange along the instantiated service paths. The NSH is the Service Function Chaining (SFC) encapsulation required to support the SFC architecture (defined in RFC 7665).

This document describes an architecture for the specification, creation, and ongoing maintenance of Service Function Chains (SFCs) in a network. It includes architectural concepts, principles, and components used in the construction of composite services through deployment of SFCs, with a focus on those to be standardized in the IETF. This document does not propose solutions, protocols, or extensions to existing protocols.

This document provides an overview of the issues associated with the deployment of service functions (such as firewalls, load balancers, etc.) in large-scale environments. The term "service function chaining" is used to describe the definition and instantiation of an ordered list of instances of such service functions, and the subsequent "steering" of traffic flows through those service functions.

The set of enabled service function chains reflects operator service offerings and is designed in conjunction with application delivery and service and network policy.

This document also identifies several key areas that the Service Function Chaining (SFC) working group will investigate to guide its architectural and protocol work and associated documents.