An MPLS-Based Forwarding Plane for Service Function Chaining
RFC 8595
| Document | Type |
RFC - Proposed Standard
(June 2019; No errata)
Was draft-ietf-mpls-sfc (mpls WG)
|
|
|---|---|---|---|
| Last updated | 2019-06-07 | ||
| Replaces | draft-farrel-mpls-sfc | ||
| Stream | IETF | ||
| Formats | plain text pdf html bibtex | ||
| Reviews | |||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Loa Andersson | ||
| Shepherd write-up | Show (last changed 2018-11-29) | ||
| IESG | IESG state | RFC 8595 (Proposed Standard) | |
| Consensus Boilerplate | Yes | ||
| Telechat date | |||
| Responsible AD | Deborah Brungard | ||
| Send notices to | Loa Andersson <loa@pi.nu> | ||
| IANA | IANA review state | Version Changed - Review Needed | |
| IANA action state | RFC-Ed-Ack | ||
Internet Engineering Task Force (IETF) A. Farrel
Request for Comments: 8595 Old Dog Consulting
Category: Standards Track S. Bryant
ISSN: 2070-1721 Futurewei
J. Drake
Juniper Networks
June 2019
An MPLS-Based Forwarding Plane for Service Function Chaining
Abstract
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.
Status of This Memo
This is an Internet Standards Track document.
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). Further information on
Internet Standards is available in 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/rfc8595.
Farrel, et al. Standards Track [Page 1]
RFC 8595 MPLS SFC June 2019
Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction ....................................................3
2. Requirements Language ...........................................4
3. Choice of Data-Plane SPI/SI Representation ......................4
4. Use Case Scenarios ..............................................5
4.1. Label Swapping for Logical NSH .............................5
4.2. Hierarchical Encapsulation .................................5
4.3. Fine Control of Service Function Instances .................6
4.4. Micro Chains and Label Stacking ............................6
4.5. SFC and Segment Routing ....................................6
5. Basic Unit of Representation ....................................6
6. MPLS Label Swapping .............................................7
7. MPLS Label Stacking ............................................10
8. Mixed-Mode Forwarding ..........................................12
9. A Note on Service Function Capabilities and SFC Proxies ........13
10. Control-Plane Considerations ..................................14
11. Use of the Entropy Label ......................................14
12. Metadata ......................................................15
12.1. Indicating Metadata in User Data Packets .................16
12.2. In-Band Programming of Metadata ..........................18
12.2.1. Loss of In-Band Metadata ..........................21
13. Worked Examples ...............................................22
14. Implementation Notes ..........................................26
15. Security Considerations .......................................26
16. IANA Considerations ...........................................28
17. References ....................................................29
17.1. Normative References .....................................29
17.2. Informative References ...................................30
Acknowledgements ..................................................31
Contributors ......................................................31
Authors' Addresses ................................................32
Farrel, et al. Standards Track [Page 2]
RFC 8595 MPLS SFC June 2019
1. Introduction
Service Function Chaining (SFC) is the process of directing packets
through a network so that they can be acted on by an ordered set of
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