Hierarchical Service Function Chaining (hSFC)
RFC 8459
Internet Engineering Task Force (IETF) D. Dolson
Request for Comments: 8459 Sandvine
Category: Experimental S. Homma
ISSN: 2070-1721 NTT
D. Lopez
Telefonica I+D
M. Boucadair
Orange
September 2018
Hierarchical Service Function Chaining (hSFC)
Abstract
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.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for examination, experimental implementation, and
evaluation.
This document defines an Experimental Protocol for the Internet
community. 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 candidates for any level of
Internet Standard; see Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8459.
Dolson, et al. Experimental [Page 1]
RFC 8459 hSFC September 2018
Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved.
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described in the Simplified BSD License.
Dolson, et al. Experimental [Page 2]
RFC 8459 hSFC September 2018
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Experiment Goals . . . . . . . . . . . . . . . . . . . . 5
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6
3. Hierarchical Service Function Chaining (hSFC) . . . . . . . . 6
3.1. Upper Level . . . . . . . . . . . . . . . . . . . . . . . 6
3.2. Lower Levels . . . . . . . . . . . . . . . . . . . . . . 8
4. Internal Boundary Node (IBN) . . . . . . . . . . . . . . . . 10
4.1. IBN Path Configuration . . . . . . . . . . . . . . . . . 10
4.1.1. Flow-Stateful IBN . . . . . . . . . . . . . . . . . . 11
4.1.2. Encoding Upper-Level Paths in Metadata . . . . . . . 12
4.1.3. Using Unique Paths per Upper-Level Path . . . . . . . 13
4.1.4. Nesting Upper-Level NSH within Lower-Level NSH . . . 13
4.1.5. Stateful/Metadata Hybrid . . . . . . . . . . . . . . 14
4.2. Gluing Levels Together . . . . . . . . . . . . . . . . . 16
4.3. Decrementing Service Index . . . . . . . . . . . . . . . 16
4.4. Managing TTL . . . . . . . . . . . . . . . . . . . . . . 16
5. Subdomain Classifier . . . . . . . . . . . . . . . . . . . . 17
6. Control Plane Elements . . . . . . . . . . . . . . . . . . . 18
7. Extension for Adapting to NSH-Unaware Service Functions . . . 18
7.1. Purpose . . . . . . . . . . . . . . . . . . . . . . . . . 19
7.2. Requirements for an IBN . . . . . . . . . . . . . . . . . 20
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21
9. Security Considerations . . . . . . . . . . . . . . . . . . . 21
9.1. Control Plane . . . . . . . . . . . . . . . . . . . . . . 21
9.2. Infinite Forwarding Loops . . . . . . . . . . . . . . . . 22
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 22
10.1. Normative References . . . . . . . . . . . . . . . . . . 22
10.2. Informative References . . . . . . . . . . . . . . . . . 22
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