Internet-Draft A. Kothari Updates: 5798, 6527 (if approved) Cisco Systems Intended Status: Standards Track August 2, 2013 Expires: February 3, 2014 VRRP Graceful Failover draft-kothari-vrrp-graceful-failover-00 Abstract This memo defines the use of priority zero in VRRP to failover from the Master router to one of the Backup routers either by operator input (i.e. manual failover) or automatically (e.g. on uplink interface going down). The procedure tries to be graceful (i.e. minimize outage) wherever possible. It is especially helpful in cases where preemption is disabled to avoid unnecessary churn. Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/1id-abstracts.html The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html Copyright and License Notice Copyright (c) 2013 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 Kothari Expires February 3, 2014 [Page 1] Internet Draft VRRP Graceful Failover August 2, 2013 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 . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 2. Updates . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.1. Summary of Updates . . . . . . . . . . . . . . . . . . . . 3 2.2. Updates to RFC5798: . . . . . . . . . . . . . . . . . . . 4 2.2.1. Updates to Section 6-4-2 of RFC5798: Backup . . . . . 4 2.2.2. Updates to Section 6-4-3 of RFC5798: Master . . . . . 5 2.3. Updates to RFC6527: . . . . . . . . . . . . . . . . . . . 6 2.3.1. Updates to Section 10 of RFC6527: Definitions . . . . 6 3. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 8 4. Security Considerations . . . . . . . . . . . . . . . . . . . 8 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8 6.1 Normative References . . . . . . . . . . . . . . . . . . . 8 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 8 Kothari Expires February 3, 2014 [Page 2] Internet Draft VRRP Graceful Failover August 2, 2013 1. Introduction Virtual Router Redundancy Protocol (VRRP) [RFC5798] defines priority zero for the purpose of indicating that the Master router has stopped participating in VRRP and the Backup routers should quickly transition to Master without waiting for the current Master to timeout. It defines it's use only during the Shutdown event in Master State. This memo defines a new "Change event" and also makes priority zero for VRRP a user configurable value. It defines it use under this new "Change event" in Master state to initiate a failover to the Backup router especially when preemption is disabled. It uses a make before break approach to minimize outage wherever possible. This document is being discussed on the vrrp@ietf.org mailing list. 1.2. Terminology 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]. 2. Updates 2.1. Summary of Updates This memo updates the following RFC sections: 1) Section 6.4.2. of [RFC5798]: o Update steps 425, and 440 of Backup State. 2) Section 6.4.3. of [RFC5798]: o Define Change event. o Update step 680, 695, 705, and 720 of Master State. 3) Section 10. of [RFC6527]: o Update vrrpv3OperationsPriority OBJECT-TYPE. o Update vrrpv3FullCompliance MODULE-COMPLIANCE. Kothari Expires February 3, 2014 [Page 3] Internet Draft VRRP Graceful Failover August 2, 2013 2.2. Updates to RFC5798: 2.2.1. Updates to Section 6-4-2 of RFC5798: Backup (420) - If an ADVERTISEMENT is received, then: (425) + If the Priority in the ADVERTISEMENT is zero, and Local Priority is greater than zero, then: (430) * Set the Master_Down_Timer to Skew_Time (440) + else // ADVERTISEMENT priority non-zero or local priority was zero Kothari Expires February 3, 2014 [Page 4] Internet Draft VRRP Graceful Failover August 2, 2013 2.2.2. Updates to Section 6-4-3 of RFC5798: Master A Change event would be triggered by change in any one of the following parameters of the VRRP Packet: 1) "Priority" Section 5.2.4 of [RFC5798] 2) "Maximum Advertisement Interval (Max Adver Int)" Section 5.2.7 of [RFC5798] 3) "IPvX Address(es)" Section 5.2.9 of [RFC5798] Handling of the Change event is only applicable in Master state as VRRP packets are not sent in other states. (680) - If the Adver_Timer fires, or Change event is received, then: (685) + Send an ADVERTISEMENT (690) + Reset the Adver_Timer to Advertisement_Interval (695) -endif // advertisement timer fired or Change event received (700) - If an ADVERTISEMENT is received, then: (705) -+ If the Priority in the ADVERTISEMENT is zero, and Local Priority is greater than zero, then: (710) -* Send an ADVERTISEMENT (715) -* Reset the Adver_Timer to Advertisement_Interval (720) -+ else // ADVERTISEMENT priority non-zero or local priority was zero Kothari Expires February 3, 2014 [Page 5] Internet Draft VRRP Graceful Failover August 2, 2013 2.3. Updates to RFC6527: 2.3.1. Updates to Section 10 of RFC6527: Definitions -- VRRPv3 Operations Table vrrpv3OperationsPriority OBJECT-TYPE SYNTAX Unsigned32 (0..255) MAX-ACCESS read-create STATUS current DESCRIPTION "This object specifies the priority to be used for the virtual router master election process; higher values imply higher priority. A priority of '0', is sent by the master router to indicate that it wants to release the Master responsibility, and a backup virtual router should transition to become a new master. A priority of 255 is used for the router that owns the associated IP address(es) for VRRP over IPv4 and hence is not setable. Setting the values of this object to 255 should be rejected by the agents implementing this MIB module. For example, an SNMP agent would return 'badValue(3)' when a user tries to set the values 255 for this object." REFERENCE "RFC 5798, Section 6.1" DEFVAL { 100 } ::= { vrrpv3OperationsEntry 7 } Kothari Expires February 3, 2014 [Page 6] Internet Draft VRRP Graceful Failover August 2, 2013 -- Compliance Statements vrrpv3FullCompliance MODULE-COMPLIANCE STATUS current DESCRIPTION "The compliance statement" MODULE -- this module MANDATORY-GROUPS { vrrpv3OperationsGroup, vrrpv3StatisticsGroup, vrrpv3InfoGroup, vrrpv3NotificationsGroup } OBJECT vrrpv3OperationsPriority WRITE-SYNTAX Unsigned32 (0..254) DESCRIPTION "Setable values are from 0 to 254." ::= { vrrpv3Compliances 1 } Kothari Expires February 3, 2014 [Page 7] Internet Draft VRRP Graceful Failover August 2, 2013 3. Acknowledgements The Author would like to thank Peter Hunt (one of the original authors of VRRP) for his inputs and review. 4. Security Considerations No new Security Considerations are introduced by this memo. The Security Considerations from [RFC5798] and [RFC6527] are still applicable. 5. IANA Considerations No new IANA Considerations are introduced by this memo. The IANA Considerations from [RFC5798] and [RFC6527] are still applicable. 6. References 6.1 Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC5798] Nadas, S., Ed., "Virtual Router Redundancy Protocol (VRRP) Version 3 for IPv4 and IPv6", RFC 5798, March 2010. [RFC6527] Tata, K., "Definitions of Managed Objects for Virtual Router Redundancy Protocol Version 3 (VRRPv3)", RFC 6527, March 2012. Author's Address Anurag Kothari Cisco Systems 7200 Kit Creek Road RTP, NC 27709 USA EMail: ankothar@cisco.com Kothari Expires February 3, 2014 [Page 8]