Information About VRRPv3: Object Tracking Integration
This section provides information about the VRRPv3 support for IPv6 Object Tracking.
Overview of VRRPv3: Object Tracking Integration
Virtual Router Redundancy Protocol (VRRP) enables a group of devices to form a single virtual device to provide redundancy. The LAN clients can then be configured with the virtual device as the default gateway. The virtual device is also known as a VRRP group. The VRRPv3: Object Tracking Integration feature allows you to track the behavior of an object and receive notifications of changes. This module explains how object tracking, in particular, the tracking of IPv6 objects, is integrated into VRRP Version 3 (VRRPv3), and describes how to track an IPv6 object using a VRRPv3 group. See the VRRP Object Tracking section for more information on object tracking.
VRRP Object Tracking
Object tracking is an independent process that manages creation, monitoring, and removal of tracked objects such as the state of the line protocol of an interface. Client processes such as the Hot Standby Router Protocol (HSRP), Gateway Load Balancing Protocol (GLBP), and VRRP register their interest with specific tracked objects and act when the state of an object changes.
Each tracked object is identified by a unique number that is specified on the tracking CLI. Client processes such as VRRP use this number to track a specific object.
The tracking process periodically polls the tracked objects and notes change of value, if any. The changes in the tracked object are communicated to interested client processes, either immediately or after a specified delay. The object values are reported as either up or down.
VRRP object tracking gives VRRP access to all the objects available through the tracking process. The tracking process allows you to track individual objects such as the state of an interface line protocol, state of an IP route, or the reachability of a route.
VRRP provides an interface to the tracking process. Each VRRP group can track multiple objects that might affect the priority of the VRRP device. You specify the object number to be tracked and VRRP is notified of changes to the object, if any. VRRP increments (or decrements) the priority of a virtual device based on the state of the object being tracked.
How VRRP Object Tracking Affects the Priority of a Device
The priority of a device can change dynamically if it has been configured for object tracking and the object that is being tracked goes down. The tracking process periodically polls the tracked objects and notes change of value, if any. The changes in the tracked object are communicated to VRRP, either immediately or after a specified delay. The object values are reported as either up or down. Examples of objects that can be tracked are the line protocol state of an interface or the reachability of an IP route. If the specified object goes down, the VRRP priority is reduced. The VRRP device with the higher priority can now become the primary virtual device if it has the vrrp preempt command configured. See the section for more information on object tracking.
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