Intarea Working Group C. Pignataro Internet-Draft Cisco Systems Updates: 2784 (if approved) R. Bonica Intended status: Standards Track Juniper Networks Expires: July 31, 2015 S. Krishnan Ericsson January 27, 2015 IPv6 Support for Generic Routing Encapsulation (GRE) draft-ietf-intarea-gre-ipv6-00 Abstract Generic Routing Encapsulation (GRE) can be used to carry any network layer protocol over any network layer protocol. GRE procedures are specified for IPv4, used as either the payload or delivery protocol. However, GRE procedures are not specified for IPv6, used as either the payload or delivery protocol. This document specifies GRE procedures for IPv6, used as either the payload or delivery protocol, and updates RFC 2784, the original GRE specification. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. 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 http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on July 31, 2015. Pignataro, et al. Expires July 31, 2015 [Page 1] Internet-Draft GRE IPv6 January 2015 Copyright Notice Copyright (c) 2015 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 (http://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 . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 2 2. GRE Header Fields . . . . . . . . . . . . . . . . . . . . . . 3 2.1. Checksum Present . . . . . . . . . . . . . . . . . . . . 3 2.2. Protocol Type . . . . . . . . . . . . . . . . . . . . . . 3 3. IPv6 as a GRE Payload . . . . . . . . . . . . . . . . . . . . 4 4. IPv6 as a GRE Delivery Protocol . . . . . . . . . . . . . . . 4 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 6. Security Considerations . . . . . . . . . . . . . . . . . . . 4 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 8. Normative References . . . . . . . . . . . . . . . . . . . . 4 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction Generic Routing Encapsulation (GRE) [RFC2784] [RFC2890] can be used to encapsulate and carry any network layer protocol (payload) over any network layer protocol (delivery). GRE procedures are specified for IPv4 [RFC0791], used as either the payload or delivery protocol. However, GRE procedures are not specified for IPv6 [RFC2460], used as either the payload or delivery protocol. This document specifies GRE procedures for IPv6, used as either the payload or delivery protocol, and updates RFC 2784 [RFC2784]. 1.1. Terminology The following terms are specific to GRE and are modeled from [RFC2784]: Pignataro, et al. Expires July 31, 2015 [Page 2] Internet-Draft GRE IPv6 January 2015 o GRE delivery header - an IPv4 or IPv6 header whose source address represents the GRE ingress node and whose destination address represents the GRE egress node. The GRE delivery header encapsulates a GRE header. o GRE header - the GRE protocol header. The GRE header is encapsulated by the GRE delivery header and encapsulates GRE payload. o GRE payload packet - a network layer packet that needs to be encapsulated and delivered to some destination, and is encapsulated by the GRE header. The following terms are specific MTU discovery: o path MTU (PMTU) - the minimum MTU of all the links in a path between a source node and a destination node. If the source and destination node are connected through equal cost multipath (ECMP), the PMTU is equal to the minimum link MTU of all links contributing to the multipath. o Path MTU Discovery (PMTUD) - A procedure for dynamically discovering the PMTU between two nodes on the Internet. PMTUD procedures for IPv6 are defined in [RFC1981]. 2. GRE Header Fields This document does not change any other fields or behaviors of the GRE specification [RFC2784] [RFC2890]. 2.1. Checksum Present The Checksum Present field SHOULD be set to zero by senders if IPv6 is used as a delivery protocol. Receivers MUST also accept a value of one in this field and use it to calculate the GRE header length but they MUST NOT verify the contents of the Checksum field. 2.2. Protocol Type The Protocol Type field contains the protocol type of the payload packet. These Protocol Types are defined in [ETYPES]. An implementation receiving a packet containing a Protocol Type which is not listed in [ETYPES] SHOULD discard the packet. Pignataro, et al. Expires July 31, 2015 [Page 3] Internet-Draft GRE IPv6 January 2015 3. IPv6 as a GRE Payload When the GRE payload is IPv6, the Protocol Type field in the GRE header MUST be set to 0x86DD. 4. IPv6 as a GRE Delivery Protocol When the GRE delivery protocol is IPv6, the GRE header can immediately follow the GRE delivery header. Alternatively, IPv6 extension headers MAY be inserted between the GRE delivery header and the GRE header. However, the IPv6 Destination Options Header MUST NOT be inserted between the GRE delivery header and the GRE header. If the GRE header immediately follows the GRE delivery header, the Next Header field in the IPv6 header of the GRE delivery packet MUST be set to the value 47. If extension headers are inserted between the GRE delivery header and the GRE header, the Next Header field in the last IPv6 extension header MUST be set to 47. Following guidance provided in Section 5 of [RFC2460], GRE ingress nodes SHOULD implement PMTUD, in order to discover and take advantage of PMTUs greater than the IPv6 required minimum (1280 octets). However, a GRE ingress node MAY simply restrict itself to sending packets no larger than 1280 octets, and omit implementation of PMTUD. 5. IANA Considerations This document makes no request of IANA. 6. Security Considerations This document adds no additional security risks to GRE, beyond what is specified in [RFC2784]. It also does not provide any additional security for GRE. 7. Acknowledgements The authors would like to thank Fred Baker, Dino Farinacci, and Andrew Yourtchenko for their thorough review and useful comments. 8. Normative References [ETYPES] IANA, "ETHER TYPES", 2014, . [RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791, September 1981. Pignataro, et al. Expires July 31, 2015 [Page 4] Internet-Draft GRE IPv6 January 2015 [RFC1981] McCann, J., Deering, S., and J. Mogul, "Path MTU Discovery for IP version 6", RFC 1981, August 1996. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6) Specification", RFC 2460, December 1998. [RFC2784] Farinacci, D., Li, T., Hanks, S., Meyer, D., and P. Traina, "Generic Routing Encapsulation (GRE)", RFC 2784, March 2000. [RFC2890] Dommety, G., "Key and Sequence Number Extensions to GRE", RFC 2890, September 2000. Authors' Addresses Carlos Pignataro Cisco Systems 7200-12 Kit Creek Road Research Triangle Park, North Carolina 27709 USA Email: cpignata@cisco.com Ron Bonica Juniper Networks 2251 Corporate Park Drive Herndon, Virginia USA Email: rbonica@juniper.net Suresh Krishnan Ericsson 8400 Decarie Blvd. Town of Mount Royal, QC Canada Phone: +1 514 345 7900 x42871 Email: suresh.krishnan@ericsson.com Pignataro, et al. Expires July 31, 2015 [Page 5]