Virtual Router Redundancy Protocol (VRRP) enables a group of devices to form a single virtual device to provide redundancy. The LAN clients then can be configured with the virtual device as the default gateway. The virtual device, representing a group of devices, 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.
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Information About VRRPv3: Object Tracking Integration
Object tracking is an independent process that manages creating, monitoring, and removing tracked objects such as the state of the line protocol of an interface. Clients 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 any change of value. 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 a 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 may affect the priority of the VRRP device. You specify the object number to be tracked and VRRP is notified of any change to the object. VRRP increments (or decrements) the priority of the virtual device based on the state of the object being tracked.
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 any change of value. 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 virtual device master if it has the vrrp preempt command configured. See the “VRRP Object Tracking” section for more information on object tracking.
How to Configure VRRPv3: Object Tracking Integration
1.
fhrp
version
vrrp
v3
2.
interface
type
number
3.
vrrp
group-id
address-family ipv6
4.
track
object-number decrement
number
5.
end
Configuration Examples for VRRPv3: Object Tracking Integration
In the following example, the tracking process is configured to track the state of the IPv6 object using the VRRPv3 group. VRRP on GigabitEthernet interface 0/0/0 then registers with the tracking process to be informed of any changes to the IPv6 object on the VRRPv3 group. If the IPv6 object state on serial interface VRRPv3 goes down, then the priority of the VRRP group is reduced by 20:
Device(config)# fhrp version vrrp v3 Device(config)# interface GigabitEthernet 0/0/0 Device(config-if)# vrrp 1 address-family ipv6 Device(config-if-vrrp)# track 1 decrement 20
Device# show vrrp
Ethernet0/0 - Group 1 - Address-Family IPv4
State is BACKUP
State duration 1 mins 41.856 secs
Virtual IP address is 172.24.1.253
Virtual MAC address is 0000.5E00.0101
Advertisement interval is 1000 msec
Preemption enabled
Priority is 80 (configured 100)
Track object 1 state Down decrement 20
Master Router is 172.24.1.2, priority is 100
Master Advertisement interval is 1000 msec (learned)
Master Down interval is 3609 msec (expires in 3297 msec)
Device# show track ipv6 route brief
Track Type Instance Parameter State Last Change
601 ipv6 route 3172::1/32 metric threshold Down 00:08:55
602 ipv6 route 3192:ABCD::1/64 metric threshold Down 00:08:55
603 ipv6 route 3108:ABCD::CDEF:1/96 metric threshold Down 00:08:55
604 ipv6 route 3162::EF01/16 metric threshold Down 00:08:55
605 ipv6 route 3289::2/64 metric threshold Down 00:08:55
606 ipv6 route 3888::1200/64 metric threshold Down 00:08:55
607 ipv6 route 7001::AAAA/64 metric threshold Down 00:08:55
608 ipv6 route 9999::BBBB/64 metric threshold Down 00:08:55
611 ipv6 route 1111::1111/64 reachability Down 00:08:55
612 ipv6 route 2222:3333::4444/64 reachability Down 00:08:55
613 ipv6 route 5555::5555/64 reachability Down 00:08:55
614 ipv6 route 3192::1/128 reachability Down 00:08:55
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Related Topic |
Document Title |
|---|---|
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Cisco IOS commands |
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HSRP commands: complete command syntax, command mode, command history, defaults, usage guidelines, and examples |
Cisco IOS First Hop Redundancy Protocols Command Reference |
|
Troubleshooting HSRP |
Hot Standby Router Protocol: Frequently Asked Questions |
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RFCs |
Title |
|---|---|
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RFC 792 |
Internet Control Message Protocol |
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RFC 1828 |
IP Authentication Using Keyed MD5 |
|
RFC 5798 |
Virtual Router Redundancy Protocol |
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Description |
Link |
|---|---|
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The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password. |
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Feature Name |
Releases |
Feature Information |
|---|---|---|
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VRRPv3: Object Tracking Integration |
Cisco IOS XE Release 3.10S |
The VRRPv3: Object Tracking Integration feature allows you to use a VRRPv3 group to track an object. The following commands were introduced or modified: fhrp version vrrp v3, show vrrp, track (VRRP). |
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