6man R. Bonica
Internet-Draft Juniper Networks
Updates: RFC 8200 (if approved) March 9, 2020
Intended status: Standards Track
Expires: September 10, 2020

Inserting, Processing And Deleting IPv6 Extension Headers
draft-bonica-6man-ext-hdr-update-02

Abstract

This document provides guidance regarding the processing, insertion and deletion of IPv6 extension headers. It updates RFC 8200.

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 September 10, 2020.

Copyright Notice

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Table of Contents

1. Introduction

In IPv6 optional internet-layer information is encoded in extension headers. As specified by [RFC8200], "extension headers (except for the Hop-by-Hop Options header) are not processed, inserted, or deleted by any node along a packet's delivery path, until the packet reaches the node (or each of the set of nodes, in the case of multicast) identified in the Destination Address field of the IPv6 header".

The statement quoted above identifies nodes upon which extension headers are not processed, inserted or deleted. It does not imply that extension headers can be processed, inserted or deleted on any other node along a packet's delivery path.

This document provides guidance regarding the processing, insertion and deletion of IPv6 extension headers. It clarifies the statement quoted above and updates [RFC8200].

2. Terminology

The following terms are used in this document:

3. Updates To RFC 8200

The terms defined in Section 2 of this document should be added to Section 2 of [RFC8200].

Section 3.1 of this document quotes text from [RFC8200]. That text should be replaced with the text contained by Section 3.2 of this document.

3.1. Original Text

"Extension headers (except for the Hop-by-Hop Options header) are not processed, inserted, or deleted by any node along a packet's delivery path, until the packet reaches the node (or each of the set of nodes, in the case of multicast) identified in the Destination Address field of the IPv6 header.

The Hop-by-Hop Options header is not inserted or deleted, but may be examined or processed by any node along a packet's delivery path, until the packet reaches the node (or each of the set of nodes, in the case of multicast) identified in the Destination Address field of the IPv6 header. The Hop-by-Hop Options header, when present, must immediately follow the IPv6 header. Its presence is indicated by the value zero in the Next Header field of the IPv6 header."

3.2. Updated Text

Source nodes can send packets that include extension headers. Extension headers are not inserted by subsequent nodes along a packet's delivery path.

The Hop-by-Hop Options header, when present, must immediately follow the IPv6 header. Its presence is indicated by the value zero in the Next Header field of the IPv6 header.

The Hop-by-Hop Options header can be processed by any node in a packet’s delivery path. The following headers can be processed by any segment egress node, including the destination node:

The following headers can be processed by the destination node only:

Except for the following fields, extension headers are not modified by nodes along a packet's delivery path:

Extension headers are not deleted by any node along a packet's delivery path, until the packet reaches the destination node (or each of the set of destination nodes, in the case of multicast).

Extension headers can be inspected for various purposes (e.g., firewall filtering) by any node along a packet's delivery path.

4. Motivation

The following are reasons why extension headers are not inserted by nodes along a packet's delivery path:

The following are reasons why extension headers are not deleted by any node along a packet's delivery path, until the packet reaches the destination node:

5. Security Considerations

This document does not introduce any new security considerations.

6. IANA Considerations

This document does not request any IANA actions.

7. Acknowledgements

Thanks to Bob Hinden, Brian Carpenter, Tom Herbert, Fernando Gont and Jinmei Tatuya for their comments and review.

8. Normative References

[RFC4302] Kent, S., "IP Authentication Header", RFC 4302, DOI 10.17487/RFC4302, December 2005.
[RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6) Specification", STD 86, RFC 8200, DOI 10.17487/RFC8200, July 2017.
[RFC8201] McCann, J., Deering, S., Mogul, J. and R. Hinden, "Path MTU Discovery for IP version 6", STD 87, RFC 8201, DOI 10.17487/RFC8201, July 2017.

Author's Address

Ron Bonica Juniper Networks 2251 Corporate Park Drive Herndon, Virginia 20171 USA EMail: rbonica@juniper.net