RFC 6864 - Updated Specification of the IPv4 ID Field

• Status: Proposed Standard
• Published: February 2013
• Stream: IETF
• Updates: RFC 791, RFC 1122, RFC 2003
• Errata: RFC Editor Errata

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Abstract

The IPv4 Identification (ID) field enables fragmentation and reassembly and, as currently specified, is required to be unique within the maximum lifetime for all datagrams with a given source address/destination address/protocol tuple. If enforced, this uniqueness requirement would limit all connections to 6.4 Mbps for typical datagram sizes. Because individual connections commonly exceed this speed, it is clear that existing systems violate the current specification. This document updates the specification of the IPv4 ID field in RFCs 791, 1122, and 2003 to more closely reflect current practice and to more closely match IPv6 so that the field's value is defined only when a datagram is actually fragmented. It also discusses the impact of these changes on how datagrams are used.

Table of Contents

• 1. Introduction
• 2. Conventions Used in This Document
• 3. The IPv4 ID Field
  • 3.1. Uses of the IPv4 ID Field
  • 3.2. Background on IPv4 ID Reassembly Issues
• 4. Updates to the IPv4 ID Specification
  • 4.1. IPv4 ID Used Only for Fragmentation
  • 4.2. Encouraging Safe IPv4 ID Use
  • 4.3. IPv4 ID Requirements That Persist
• 5. Impact of Proposed Changes
  • 5.1. Impact on Legacy Internet Devices
  • 5.2. Impact on Datagram Generation
  • 5.3. Impact on Middleboxes
    • 5.3.1. Rewriting Middleboxes
    • 5.3.2. Filtering Middleboxes
  • 5.4. Impact on Header Compression
  • 5.5. Impact of Network Reordering and Loss
    • 5.5.1. Atomic Datagrams Experiencing Reordering or Loss
    • 5.5.2. Non-atomic Datagrams Experiencing Reordering or Loss
• 6. Updates to Existing Standards
  • 6.1. Updates to RFC 791
  • 6.2. Updates to RFC 1122
  • 6.3. Updates to RFC 2003
• 7. Security Considerations
• 8. References
  • 8.1. Normative References
  • 8.2. Informative References
• 9. Acknowledgments
• Author's Address

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 5741. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc6864.

Copyright Notice

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