6man R. Bonica
Internet-Draft Juniper Networks
Intended status: Standards Track J. Halpern
Expires: January 8, 2020 Ericsson
Y. Kamite
NTT Communications Corporation
T. Niwa
KDDI
N. So
F. Xu
Reliance Jio
G. Chen
Baidu
Y. Zhu
G. Yang
China Telecom
Y. Zhou
ByteDance
July 7, 2019

The Per-Segment Service Instruction (PSSI) Option
draft-bonica-6man-seg-end-opt-04

Abstract

SRv6+ encodes Per-Segment Service Instructions (PSSI) in a new IPv6 option, called the PSSI Option. This document describes the PSSI Option.

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.

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This Internet-Draft will expire on January 8, 2020.

Copyright Notice

Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved.

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Table of Contents

1. Introduction

An SRv6+ path provides unidirectional connectivity from its ingress node to its egress node. While an SRv6+ path can follow the least cost path from ingress to egress, it can also follow any other path.

An SRv6+ path contains one or more segments. A segment provides unidirectional connectivity from its ingress node to its egress node.

SRv6+ paths are programmable. They support several instruction types, including Per-Segment Service Instructions (PSSI). The following are examples of PSSIs:

PSSIs are executed at segment egress nodes and can be used to implement limited service chains. However, they do not provide an alternative to the Network Service Header (NSH).

SRv6+ encodes PSSIs in a new IPv6 option, called the PSSI Option. This document describes the PSSI Option.

2. Requirements Language

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC8174] when, and only when, they appear in all capitals, as shown here.

3. PSSI Identifiers

PSSI Identifiers identify PSSIs. They have domain-wide significance. When a controller creates a limited service chain, also allocates a PSSI Identifier. It then distributes the following information to each node that contributes to the limited service chain:

4. Option Format

The PSSI Option contains the following fields:

The PSSI option MAY appear in any Destination Options header, regardless of whether that Destination Options header precedes a Routing header or an upper-layer header. The PSSI option MUST NOT appear in a Hop-by-hop Options header.

NOTE : The highest-order two bits of the Option Type (i.e., the "act" bits) are 00. These bits specify the action taken by a destination node that does not recognize the option. The required action is to skip over this option and continue processing the header.

The third highest-order bit of the Option Type (i.e., the "chg" bit) is 0. This indicates that Option Data cannot be modified along the path between the packet's source and its destination.

5. Security Considerations

The PSSI option shares many security concerns with IPv6 routing headers. In particular, any boundary filtering protecting a domain from external routing headers should also protect against external PSSI options being processed inside a domain. This occurs naturally if encapsulation is used to add routing headers to a packet. If external routing headers are allowed, then protections must also include ensuring that any provided PSSI option is properly protected, e.g. with an IPSEC AH header or other suitable means.

As with Routing headers, the security assumption within a domain is that the domain is trusted to provide, and to avoid improperly modifying, the PSSI Option.

6. IANA Considerations

IANA is requested to allocate a cod epoint from the Destination Options and Hop-by-hop Options registry (https://www.iana.org/assignments/ipv6-parameters/ipv6-parameters.xhtml#ipv6-parameters-2). This option is called "PSSI". The "act" bits are 00 and the "chg" bit is 0. (Suggested value: 0x10).

7. Acknowledgements

Thanks to Fred Baker and Shizhang Bi for their careful review of this document.

8. Normative References

[I-D.bonica-spring-srv6-plus] Bonica, R., Hegde, S., Kamite, Y., Alston, A., Henriques, D., Halpern, J. and J. Linkova, "IPv6 Support for Segment Routing: SRv6+", Internet-Draft draft-bonica-spring-srv6-plus-03, July 2019.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997.
[RFC4443] Conta, A., Deering, S. and M. Gupta, "Internet Control Message Protocol (ICMPv6) for the Internet Protocol Version 6 (IPv6) Specification", STD 89, RFC 4443, DOI 10.17487/RFC4443, March 2006.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017.
[RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6) Specification", STD 86, RFC 8200, DOI 10.17487/RFC8200, July 2017.
[RFC8300] Quinn, P., Elzur, U. and C. Pignataro, "Network Service Header (NSH)", RFC 8300, DOI 10.17487/RFC8300, January 2018.

Authors' Addresses

Ron Bonica Juniper Networks 2251 Corporate Park Drive Herndon, Virginia 20171 USA EMail: rbonica@juniper.net
Joel Halpern Ericsson P. O. Box 6049 Leesburg, Virginia 20178 USA EMail: joel.halpern@ericsson.com
Yuji Kamite NTT Communications Corporation 3-4-1 Shibaura, Minato-ku Tokyo, 108-8118 Japan EMail: : y.kamite@ntt.com
Tomonobu Niwa KDDI 3-22-7, Yoyogi, Shibuya-ku Tokyo, 151-0053 JP EMail: to-niwa@kddi.com
Ning So Reliance Jio 3010 Gaylord PKWY, Suite 150 Frisco, Texas 75034 USA EMail: Ning.So@ril.com
Fengman Xu Reliance Jio 3010 Gaylord PKWY, Suite 150 Frisco, Texas 75034 USA EMail: Fengman.Xu@ril.com
Gang Chen Baidu No.10 Xibeiwang East Road Haidian District Beijing, 100193 P.R. China EMail: phdgang@gmail.com
Yongqing Zhu China Telecom 109 West Zhongshan Ave, Tianhe District Guangzhou, P.R. China EMail: zhuyq.gd@chinatelecom.cn
Guangming Yang China Telecom 109 West Zhongshan Ave, Tianhe District Guangzhou, P.R. China EMail: yanggm.gd@chinatelecom.cn
Yifeng Zhou ByteDance Building 1, AVIC Plaza, 43 N 3rd Ring W Rd Haidian District Beijing, 100000 P.R. China EMail: yifeng.zhou@bytedance.com