--- 1/draft-ietf-vrrp-ipv6-spec-00.txt 2006-02-05 02:09:29.000000000 +0100 +++ 2/draft-ietf-vrrp-ipv6-spec-01.txt 2006-02-05 02:09:29.000000000 +0100 @@ -1,44 +1,47 @@ INTERNET-DRAFT R. Hinden/Nokia -October 22, 2001 +November 20, 2001 Virtual Router Redundancy Protocol for IPv6 - + Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of [RFC2026]. 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." - To view the list Internet-Draft Shadow Directories, see - http://www.ietf.org/shadow.html. + The list of current Internet-Drafts can be accessed at + http://www.ietf.org/1id-abstracts.html - This internet draft expires on April 22, 2002. + The list of Internet-Draft Shadow Directories can be accessed at + http://www.ietf.org/shadow.html + + This internet draft expires on May 20, 2002. Abstract This memo defines the Virtual Router Redundancy Protocol (VRRP) for IPv6. It is version three (3) of the protocol. It is based on the original version of VRRP (version 2) for IPv4 that is defined in - RFC2238. + RFC2338. VRRP specifies an election protocol that dynamically assigns responsibility for a virtual router to one of the VRRP routers on a LAN. The VRRP router controlling the IP address associated with a virtual router is called the Master, and forwards packets sent to this IP address. The election process provides dynamic fail over in the forwarding responsibility should the Master become unavailable. The advantage gained from using VRRP for IPv6 is a quicker switch over to back up routers than can be obtained with standard IPv6 Neighbor Discovery [ND] mechanisms. @@ -86,21 +89,21 @@ IPv6 hosts on a LAN will usually learn about one or more default routers by receiving Router Advertisements sent using the IPv6 Neighbor Discovery protocol [ND]. The Router Advertisements are multicast periodically at a rate that the hosts will learn about the default routers in a few minutes. They are not sent frequently enough to rely on the absence of the router advertisement to detect router failures. Neighbor Discovery (ND) includes a mechanism called Neighbor - Unreachablity Detection to detect the failure of a neighbor node + Unreachability Detection to detect the failure of a neighbor node (router or host) or the forwarding path to a neighbor. This is done by sending unicast ND Neighbor Solicitation messages to the neighbor node. To reduce the overhead of sending Neighbor Solicitations, they are only sent to neighbors to which the node is actively sending traffic and only after there has been no positive indication that the router is up for a period of time. Using the default parameters in ND, it will take a host about 38 seconds to learn that a router is unreachable before it will switch to another default router. This delay would be very noticeable to users and cause some transport protocol implementations to timeout. @@ -276,24 +279,24 @@ with its real address on an interface, and may also be configured with additional virtual router mappings and priority for virtual routers it is willing to backup. The mapping between VRID and it's IPv6 address must be coordinated among all VRRP routers on a LAN. However, there is no restriction against reusing a VRID with a different address mapping on different LANs. The scope of each virtual router is restricted to a single LAN. To minimize network traffic, only the Master for each virtual router sends periodic VRRP Advertisement messages. A Backup router will not - attempt to pre-empt the Master unless it has higher priority. This + attempt to preempt the Master unless it has higher priority. This eliminates service disruption unless a more preferred path becomes - available. It's also possible to administratively prohibit all pre- - emption attempts. The only exception is that a VRRP router will + available. It's also possible to administratively prohibit all + preemption attempts. The only exception is that a VRRP router will always become Master of any virtual router associated with address it owns. If the Master becomes unavailable then the highest priority Backup will transition to Master after a short delay, providing a controlled transition of the virtual router responsibility with minimal service interruption. VRRP defines three types of authentication providing simple deployment in insecure environments, added protection against misconfiguration, and strong sender authentication in security conscious environments. Analysis of the protection provided and @@ -651,21 +654,21 @@ (3 * Advertisement_Interval) + Skew_time Preempt_Mode Controls whether a higher priority Backup router preempts a lower priority Master. Values are True to allow preemption and False to prohibit preemption. Default is True. Note: Exception is that the router that owns the IPv6 address associated with the virtual - router always pre-empts independent of the + router always preempts independent of the setting of this flag. Authentication_Type Type of authentication being used. Values are defined in section 5.3.6. Authentication_Data Authentication data specific to the Authentication_Type being used. 6.2 Timers @@ -1224,25 +1227,25 @@ Thomas Narten, and Steve Deering for their his helpful suggestions. 13. IANA Considerations VRRP for IPv6 needs an IPv6 link-local scope multicast address assigned by the IANA for this specification. The IPv6 multicast address should be of the following form: FF02:0:0:0:0:0:XXXX:XXXX - The values assgned address should be entered into section 5.2.2. + The values assigned address should be entered into section 5.2.2. A convenient assignment of this link-local scope multicast would be: - FF02:0:0:0:0:0:1:2 + FF02:0:0:0:0:0:0:12 as this would be consistent with the IPv4 assignment for VRRP. 14. References [802.1D] International Standard ISO/IEC 10038: 1993, ANSI/IEEE Std 802.1D, 1993 edition. [ADD-ARH] Hinden, R., S. Deering, "IP Version 6 Addressing Architecture", RFC2373, July 1988.