Geneve: Generic Network Virtualization Encapsulation
RFC 8926

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Internet Engineering Task Force (IETF)                     J. Gross, Ed.
Request for Comments: 8926                                              
Category: Standards Track                                  I. Ganga, Ed.
ISSN: 2070-1721                                                    Intel
                                                         T. Sridhar, Ed.
                                                                  VMware
                                                           November 2020

          Geneve: Generic Network Virtualization Encapsulation

Abstract

   Network virtualization involves the cooperation of devices with a
   wide variety of capabilities such as software and hardware tunnel
   endpoints, transit fabrics, and centralized control clusters.  As a
   result of their role in tying together different elements of the
   system, the requirements on tunnels are influenced by all of these
   components.  Therefore, flexibility is the most important aspect of a
   tunneling protocol if it is to keep pace with the evolution of
   technology.  This document describes Geneve, an encapsulation
   protocol designed to recognize and accommodate these changing
   capabilities and needs.

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/rfc8926.

Copyright Notice

   Copyright (c) 2020 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
     1.1.  Requirements Language
     1.2.  Terminology
   2.  Design Requirements
     2.1.  Control Plane Independence
     2.2.  Data Plane Extensibility
       2.2.1.  Efficient Implementation
     2.3.  Use of Standard IP Fabrics
   3.  Geneve Encapsulation Details
     3.1.  Geneve Packet Format over IPv4
     3.2.  Geneve Packet Format over IPv6
     3.3.  UDP Header
     3.4.  Tunnel Header Fields
     3.5.  Tunnel Options
       3.5.1.  Options Processing
   4.  Implementation and Deployment Considerations
     4.1.  Applicability Statement
     4.2.  Congestion-Control Functionality
     4.3.  UDP Checksum
       4.3.1.  Zero UDP Checksum Handling with IPv6
     4.4.  Encapsulation of Geneve in IP
       4.4.1.  IP Fragmentation
       4.4.2.  DSCP, ECN, and TTL
       4.4.3.  Broadcast and Multicast
       4.4.4.  Unidirectional Tunnels
     4.5.  Constraints on Protocol Features
       4.5.1.  Constraints on Options
     4.6.  NIC Offloads
     4.7.  Inner VLAN Handling
   5.  Transition Considerations
   6.  Security Considerations
     6.1.  Data Confidentiality
       6.1.1.  Inter-Data Center Traffic
     6.2.  Data Integrity
     6.3.  Authentication of NVE Peers
     6.4.  Options Interpretation by Transit Devices
     6.5.  Multicast/Broadcast
     6.6.  Control Plane Communications
   7.  IANA Considerations
   8.  References
     8.1.  Normative References
     8.2.  Informative References
   Acknowledgements
   Contributors
   Authors' Addresses

1.  Introduction

   Networking has long featured a variety of tunneling, tagging, and
   other encapsulation mechanisms.  However, the advent of network
   virtualization has caused a surge of renewed interest and a
   corresponding increase in the introduction of new protocols.  The
   large number of protocols in this space -- for example, ranging all
   the way from VLANs [IEEE.802.1Q_2018] and MPLS [RFC3031] through the
   more recent VXLAN (Virtual eXtensible Local Area Network) [RFC7348]
   and NVGRE (Network Virtualization Using Generic Routing
   Encapsulation) [RFC7637] -- often leads to questions about the need
   for new encapsulation formats and what it is about network
   virtualization in particular that leads to their proliferation.  Note
   that the list of protocols presented above is non-exhaustive.

   While many encapsulation protocols seek to simply partition the
   underlay network or bridge two domains, network virtualization views