DHCPv6 Failover Protocol
RFC 8156
Internet Engineering Task Force (IETF) T. Mrugalski
Request for Comments: 8156 ISC
Category: Standards Track K. Kinnear
ISSN: 2070-1721 Cisco
June 2017
DHCPv6 Failover Protocol
Abstract
DHCPv6 as defined in "Dynamic Host Configuration Protocol for IPv6
(DHCPv6)" (RFC 3315) does not offer server redundancy. This document
defines a protocol implementation to provide DHCPv6 failover, a
mechanism for running two servers with the capability for either
server to take over clients' leases in case of server failure or
network partition. It meets the requirements for DHCPv6 failover
detailed in "DHCPv6 Failover Requirements" (RFC 7031).
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
http://www.rfc-editor.org/info/rfc8156.
Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved.
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described in the Simplified BSD License.
Mrugalski & Kinnear Standards Track [Page 1]
RFC 8156 DHCPv6 Failover Protocol June 2017
Table of Contents
1. Introduction ....................................................5
2. Requirements Language ...........................................5
3. Glossary ........................................................6
4. Failover Concepts and Mechanisms ...............................10
4.1. Required Server Configuration .............................10
4.2. IPv6 Address and Delegable Prefix Allocation ..............10
4.2.1. Independent Allocation .............................10
4.2.1.1. Independent Allocation Algorithm ..........11
4.2.2. Proportional Allocation ............................11
4.2.2.1. Reallocating Leases .......................13
4.3. Lazy Updates ..............................................14
4.4. Maximum Client Lead Time (MCLT) ...........................14
4.4.1. MCLT Example .......................................16
5. Message and Option Definitions .................................19
5.1. Message Framing for TCP ...................................19
5.2. Failover Message Format ...................................19
5.3. Messages ..................................................20
5.3.1. BNDUPD .............................................20
5.3.2. BNDREPLY ...........................................20
5.3.3. POOLREQ ............................................20
5.3.4. POOLRESP ...........................................21
5.3.5. UPDREQ .............................................21
5.3.6. UPDREQALL ..........................................21
5.3.7. UPDDONE ............................................21
5.3.8. CONNECT ............................................21
5.3.9. CONNECTREPLY .......................................22
5.3.10. DISCONNECT ........................................22
5.3.11. STATE .............................................22
5.3.12. CONTACT ...........................................22
5.4. Transaction-id ............................................22
5.5. Options ...................................................23
5.5.1. OPTION_F_BINDING_STATUS ............................23
5.5.2. OPTION_F_CONNECT_FLAGS .............................24
5.5.3. OPTION_F_DNS_REMOVAL_INFO ..........................25
5.5.3.1. OPTION_F_DNS_HOST_NAME ....................26
5.5.3.2. OPTION_F_DNS_ZONE_NAME ....................26
5.5.3.3. OPTION_F_DNS_FLAGS ........................27
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