Service Function Chaining (SFC) Architecture
RFC 7665
Internet Engineering Task Force (IETF) J. Halpern, Ed.
Request for Comments: 7665 Ericsson
Category: Informational C. Pignataro, Ed.
ISSN: 2070-1721 Cisco
October 2015
Service Function Chaining (SFC) Architecture
Abstract
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.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7665.
Halpern & Pignataro Informational [Page 1]
RFC 7665 SFC Architecture October 2015
Copyright Notice
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Halpern & Pignataro Informational [Page 2]
RFC 7665 SFC Architecture October 2015
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2. Assumptions . . . . . . . . . . . . . . . . . . . . . . . 5
1.3. Specification of Requirements . . . . . . . . . . . . . . 5
1.4. Definition of Terms . . . . . . . . . . . . . . . . . . . 6
2. Architectural Concepts . . . . . . . . . . . . . . . . . . . 8
2.1. Service Function Chains . . . . . . . . . . . . . . . . . 8
2.2. Service Function Chain Symmetry . . . . . . . . . . . . . 9
2.3. Service Function Paths . . . . . . . . . . . . . . . . . 10
2.3.1. Service Function Chains, Service Function Paths, and
Rendered Service Path . . . . . . . . . . . . . . . . 11
3. Architecture Principles . . . . . . . . . . . . . . . . . . . 12
4. Core SFC Architecture Components . . . . . . . . . . . . . . 13
4.1. SFC Encapsulation . . . . . . . . . . . . . . . . . . . . 14
4.2. Service Function (SF) . . . . . . . . . . . . . . . . . . 15
4.3. Service Function Forwarder (SFF) . . . . . . . . . . . . 15
4.3.1. Transport-Derived SFF . . . . . . . . . . . . . . . . 17
4.4. SFC-Enabled Domain . . . . . . . . . . . . . . . . . . . 17
4.5. Network Overlay and Network Components . . . . . . . . . 18
4.6. SFC Proxy . . . . . . . . . . . . . . . . . . . . . . . . 18
4.7. Classification . . . . . . . . . . . . . . . . . . . . . 19
4.8. Reclassification and Branching . . . . . . . . . . . . . 19
4.9. Shared Metadata . . . . . . . . . . . . . . . . . . . . . 20
5. Additional Architectural Concepts . . . . . . . . . . . . . . 21
5.1. The Role of Policy . . . . . . . . . . . . . . . . . . . 21
5.2. SFC Control Plane . . . . . . . . . . . . . . . . . . . . 21
5.3. Resource Control . . . . . . . . . . . . . . . . . . . . 22
5.4. Infinite Loop Detection and Avoidance . . . . . . . . . . 23
5.5. Load-Balancing Considerations . . . . . . . . . . . . . . 23
5.6. MTU and Fragmentation Considerations . . . . . . . . . . 24
5.7. SFC OAM . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.8. Resilience and Redundancy . . . . . . . . . . . . . . . . 26
6. Security Considerations . . . . . . . . . . . . . . . . . . . 27
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