RFC 9568, "Virtual Router Redundancy Protocol (VRRP) Version 3 for IPv4 and IPv6", April 2024

Errata ID: 8301
Status: Verified
Type: Technical
Publication Format(s) : TEXT, PDF, HTML
Reported By: Quentin Armitage
Date Reported: 2025-02-17
Verifier Name: Jim Guichard
Date Verified: 2025-03-06

Section 6.1 says:

Advertisement_Interval  Time interval between VRRP Advertisements
   (centiseconds) sent by this Virtual Router. Default is 100
   centiseconds (1 second).


 and section 7.1 says:

 * It MUST verify that the VRID is configured on the receiving
   interface and the local router is not the IPvX address owner
   (Priority = 255 (decimal)).

If any one of the above checks fails, the receiver MUST discard the
packet, SHOULD log the event (subject to rate-limiting), and MAY
indicate via network management that an error occurred.

It should say:

Advertisement_Interval  Time interval between VRRP Advertisements
   (centiseconds) sent by this Virtual Router. Configurable value
   in the range 1-4095 (centiseconds). Default is 100 centiseconds
   (1 second).

 and section 7.1 should say:

 * It MUST verify that the VRID is configured on the receiving
   interface and the local router is not the IPvX address owner
   (Priority = 255 (decimal)).

 *  It MUST verify that the Max Advertise Interval is non zero.

If any one of the above checks fails, the receiver MUST discard the
packet, SHOULD log the event (subject to rate-limiting), and MAY
indicate via network management that an error occurred.

Notes:

The Skew_Time and Active_Down_Time are calculated by multiplying by Active_Adver_Interval which is the Advertisement_Interval of the current active virtual router. A value of 0 for the Active_Adver_Interval will result in Skew_Time and Active_Down_Interval being 0 (centiseconds). The consequence of this is that all backup routers will immediately time out the Active_Down_Interval and transition to Active state. All but the lowest priority virtual router will send an advert, all virtual routes will keep timing out and sending VRRP adverts and the LAN will be flooded with VRRP packets.

It causes mayhem (I have tried it)!

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