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Table Of Contents
Information About Enhanced Object Tracking
Feature Design of Enhanced Object Tracking
Benefits of Enhanced Object Tracking
How to Configure Enhanced Object Tracking
Tracking the IP-Routing State of an Interface
Tracking the Line-Protocol State of an Interface
Tracking IP-Route Reachability
Tracking the Threshold of IP-Route Metrics
Configuring a Tracked List and Boolean Expression
Configuring a Tracked List and Threshold Weight
Configuring a Tracked List and Threshold Percentage
Configuring the Track List Defaults
Configuring HSRP Object Tracking
Configuring the Polling Interval
Verifying Enhanced Object Tracking
Configuration Examples for Enhanced Object Tracking
Interface Line Protocol: Example
IP-Route Reachability: Example
IP-Route Threshold Metric: Example
Threshold Weight for a Tracked List Configuration: Example
Threshold Percentage for a Tracked List Configuration: Example
Boolean Expression for a Tracked List Configuration: Example
Enhanced Object Tracking
Prior to the introduction of the Enhanced Object Tracking feature, the Hot Standby Router Protocol (HSRP) had a simple tracking mechanism that allowed you to track the interface line-protocol state only. If the line-protocol state of the interface went down, the HSRP priority of the router was reduced, allowing another HSRP router with a higher priority to become active.
The Enhanced Object Tracking feature separates the tracking mechanism from HSRP and creates a separate standalone tracking process that can be used by any other process as well as HSRP. This feature allows tracking of other objects in addition to the interface line-protocol state.
A client process, such as HSRP, Virtual Router Redundancy Protocol (VRRP), or Gateway Load Balancing Protocol (GLBP), can now register its interest in tracking objects and then be notified when the tracked object changes state. The object can be an interface or a route.
Feature History for the Enhanced Object Tracking Feature
Finding Support Information for Platforms and Cisco IOS Software Images
Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://www.cisco.com/go/fn. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.
Contents
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Information About Enhanced Object Tracking
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Information About Enhanced Object Tracking
Before you configure the Enhanced Object Tracking feature, you should understand the following concepts:
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Feature Design of Enhanced Object Tracking
The Enhanced Object Tracking feature provides complete separation between the objects to be tracked and the action to be taken by a client when a tracked object changes. Thus, several clients such as HSRP, VRRP, or GLPB can register their interest with the tracking process, track the same object, and each take different action when the object changes.
Each tracked object is identified by a unique number that is specified on the tracking command-line interface (CLI). Client processes 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.
In this release, the tracking capabilities have been enhanced to enable the configuration of a combination of tracked objects in a list, and a flexible method of combining objects using Boolean logic. The enhancements introduced the following capabilities:
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Benefits of Enhanced Object Tracking
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How to Configure Enhanced Object Tracking
The following sections describe configuration tasks for enhanced object tracking:
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Tracking the IP-Routing State of an Interface
Perform this task to track the IP-routing state of an interface. An IP-routing object is considered up when the following criteria exist:
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Interface IP routing will go down when one of the following criteria exist:
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Tracking the IP-routing state of an interface using the track interface ip routing command can be more useful in some situations than just tracking the line-protocol state using the track interface line-protocol command, especially on interfaces for which IP addresses are negotiated. For example, on a serial interface that uses the Point-to-Point Protocol (PPP), the line protocol could be up [link control protocol (LCP) negotiated successfully], but IP could be down (IPCP negotiation failed).
The track interface ip routing command supports the tracking of an interface with an IP address acquired through any of the following methods:
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SUMMARY STEPS
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DETAILED STEPS
Tracking the Line-Protocol State of an Interface
Perform this task to track the line-protocol state of an interface.
SUMMARY STEPS
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DETAILED STEPS
Tracking IP-Route Reachability
Perform this task to track the reachability of an IP route. A tracked object is considered up when a routing table entry exists for the route and the route is accessible.
SUMMARY STEPS
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DETAILED STEPS
Tracking the Threshold of IP-Route Metrics
Perform this task to track the threshold of IP route metrics.
Scaled Route Metrics
The track ip route command enables tracking of a route in the routing table. If a route exists in the table, the metric value is converted into a number. To provide a common interface to tracking clients, route metric values are normalized to the range from 0 to 255, where 0 is connected and 255 is inaccessible. Scaled metrics can be tracked by setting thresholds. Up and down state notification occurs when the thresholds are crossed. The resulting value is compared against threshold values to determine the tracking state as follows:
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Tracking uses a per-protocol configurable resolution value to convert the real metric to the scaled metric. Table 1 shows the default values used for the conversion. You can use the track resolution command to change the metric resolution default values.
Table 1 Metric Conversion
Static
10
Enhanced Interior Gateway Routing Protocol (EIGRP)
2560
Open Shortest Path First (OSPF)
1
Intermediate System-to-Intermediate System (IS-IS)
10
1 RIP is scaled directly to the range from 0 to 255 because its
maximum metric is less than 255.
For example, a change in 10 in an IS-IS metric results in a change of 1 in the scaled metric. The default resolutions are designed so that approximately one 2-Mbps link in the path will give a scaled metric of 255.
Scaling the very large metric ranges of EIGRP and IS-IS to a 0 to 255 range is a compromise. The default resolutions will cause the scaled metric to go above the maximum limit with a 2-Mbps link. However, this scaling allows a distinction between a route consisting of three Fast-Ethernet links and a route consisting of four Fast-Ethernet links.
SUMMARY STEPS
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DETAILED STEPS
Configuring a Tracked List and Boolean Expression
Perform this task to configure a tracked list of objects and a Boolean expression to determine the state of the list. A tracked list contains one or more objects. The Boolean expression enables two types of calculation by using either "and" or "or" operators. For example, when tracking two interfaces using the "and" operator, up means that both interfaces are up, and down means that either interface is down.
You may also configure a tracked list state to be measured using a weight or percentage threshold. See "Configuring a Tracked List and Threshold Weight" section and "Configuring a Tracked List and Threshold Percentage" section.
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Prerequisites
An object must exist before it can be added to a tracked list.
SUMMARY STEPS
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DETAILED STEPS
Examples
The following configuration example shows that tracked list 4 has two objects and one object state is negated (if the list is up, the list detects that object 2 is down):
track 4 list boolean andobject 1object 2 notConfiguring a Tracked List and Threshold Weight
Perform this task to configure a tracked list of objects, to specify that weight be used as the threshold, and to configure a weight for each of its objects. A tracked list contains one or more objects. Using a weight threshold the state of each object is determined by comparing the total weight of all objects that are up against a threshold weight for each object.
You may also configure a tracked list state to be measured using a Boolean calculation or threshold percentage. See "Configuring a Tracked List and Boolean Expression" section and "Configuring a Tracked List and Threshold Percentage" section.
Prerequisites
An object must exist before it can be added to a tracked list.
Restrictions
You cannot use the Boolean "not" operator in a weight or percentage threshold list.
SUMMARY STEPS
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Examples
The following configuration example shows that if object 1, and object 2 are down, then track list 4 is up, because object 3 satisfies the up threshold value of up 30. But, if object 3 is down, both objects 1 and 2 need to be up in order to satisfy the threshold weight.
track 4 list threshold weightobject 1 weight 15object 2 weight 20object 3 weight 30threshold weight up 30 down 10This configuration may be useful to you if you have two small bandwidth connections (represented by object 1 and 2) and one large bandwidth connection (represented by object 3). Also the down 10 value means that once the tracked object is up, it will not go down until the threshold value is lower or equal to 10, which in this example means that all connections are down.
Configuring a Tracked List and Threshold Percentage
Perform this task to configure a tracked list of objects, to specify that a percentage will be used as the threshold, and to specify a percentage for each object in the list. A tracked list contains one or more objects. Using the percentage threshold, the state of the list is determined by comparing the assigned percentage of each object to the list.
You may also configure a tracked list state to be measured using a Boolean calculation or threshold weight. See "Configuring a Tracked List and Boolean Expression" section and "Configuring a Tracked List and Threshold Weight" section.
Prerequisites
An object must exist before it can be added to a tracked list.
Restrictions
You cannot use the Boolean "not" operator in a weight or percentage threshold lists.
SUMMARY STEPS
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DETAILED STEPS
Examples
The following configuration example shows that tracked list 4 has three objects and specified percentages to measure the state of the list:
track 4 list threshold percentageobject 1object 2object 3threshold percentage up 51 down 10Configuring the Track List Defaults
Perform this task to configure a default delay value for a tracked list, a default object, and default threshold parameters for a tracked list.
SUMMARY STEPS
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DETAILED STEPS
Configuring HSRP Object Tracking
Perform this task to configure a standby HSRP group to track an object and change the HSRP priority on the basis of the object state.
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SUMMARY STEPS
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DETAILED STEPS
Step 1
enable
Example:Router> enable
Enables privileged EXEC mode.
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Step 2
configure terminal
Example:Router# configure terminal
Enters global configuration mode.
Step 3
track object-number interface type-number {line-protocol | ip routing}
Example:Router(config)# track 100 interface serial2/0 line-protocol
Configures an interface to be tracked and enters tracking configuration mode.
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Step 4
exit
Example:Router(config-track)# exit
Returns to global configuration mode.
Step 5
interface type number
Example:Router(config)# interface ethernet 2
Enters interface configuration mode.
Step 6
standby [group-number] ip [ip-address [secondary]]
Example:Router(config-if)# standby 1 ip 10.10.10.0
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standby [group-number] track object-number [decrement [priority-decrement]]
Example:Router(config-if)# standby 1 track 100 decrement 20
Configures HSRP to track an object and change the Hot Standby priority on the basis of the state of the object.
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Step 8
exit
Example:Router(config-if)# exit
Returns to privileged EXEC mode.
Examples
In the following configuration example, the tracking process is configured to track the IP-routing capability of serial interface 1/0. HSRP on Ethernet interface 0/0 then registers with the tracking process to be informed of any changes to the IP-routing state of serial interface 1/0. If the IP state on serial interface 1/0 goes down, the priority of the HSRP group is reduced by 10.
If both serial interfaces are operational, Router A will be the HSRP active router because it has the higher priority. However, if IP routing on serial interface 1/0 in Router A fails, the HSRP group priority will be reduced and Router B will take over as the active router, thus maintaining a default virtual gateway service to hosts on the 10.1.0.0 subnet.
Router A Configuration
track 100 interface serial1/0 ip routing!interface Ethernet0/0ip address 10.1.0.21 255.255.0.0standby 1 preemptstandby 1 ip 10.1.0.1standby 1 priority 110standby 1 track 100 decrement 10Router B Configuration
track 100 interface serial1/0 ip routing!interface Ethernet0/0ip address 10.1.0.22 255.255.0.0standby 1 preemptstandby 1 ip 10.1.0.1standby 1 priority 105standby 1 track 100 decrement 10Configuring the Polling Interval
Perform this task to configure the tracking process to periodically poll the tracked objects. The tracking process notes any changes of value. The changes are communicated to interested client processes, either immediately or after a specified delay.
SUMMARY STEPS
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Verifying Enhanced Object Tracking
Perform the following steps to verify that the specified objects are being tracked.
SUMMARY STEPS
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DETAILED STEPS
Step 1
Use this command to display the IP-routing state of an interface when it is tracked, for example:
Router# show track 1Track 1Interface Ethernet0/1 ip routingIP routing is Up1 change, last change 00:01:08Tracked by:HSRP Ethernet0/3 1In the following example, the state of the line protocol on an interface when it is tracked is displayed:
Router# show track 3Track 3Interface Ethernet0/1 line-protocolLine protocol is Up1 change, last change 00:00:05Tracked by:HSRP Ethernet0/3 1In the following example, the state of the reachability of an IP route when it is tracked is displayed:
Router# show track 4Track 4IP route 10.16.0.0 255.255.0.0 reachabilityReachability is Up (RIP)1 change, last change 00:02:04First-hop interface is Ethernet0/1Tracked by:HSRP Ethernet0/3 1In the following example, the threshold metric of an IP route when it is tracked is displayed:
Router# show track 6Track 6IP route 10.16.0.0 255.255.0.0 metric thresholdMetric threshold is Up (RIP/6/102)1 change, last change 00:00:08Metric threshold down 255 up 254First-hop interface is Ethernet0/1Tracked by:HSRP Ethernet0/3 1In the following example, the method of object tracking in a list is displayed:
Router# show trackTrack 6List threshold weightThreshold weight is Up (20/30)1 change, last change 00:00:08object 1 Down (0/10)object 2 weight 20 Up (20/30)Threshold weight down 10 up 20Tracked by:HSRP Ethernet0/3 1This output shows that there are two objects. Object 1 has been configured with a weight of 10 down, and object 2 has been configured with a weight of 20 up. Object 1 is down (expressed as 0/10) and object 2 is up. The total weight of the tracked list is 20 with a maximum of 30 (expressed as 20/30). The up threshold is 20, so the list is up.
Step 2
Use this command to verify that the standby router has an IP address of 10.10.10.10 and group 3 is active, for example:
Router# show standbyEthernet0/1 - Group 3State is Active2 state changes, last state change 00:01:25Virtual IP address is 10.21.0.10Active virtual MAC address is 0000.0c07.ac03Local virtual MAC address is 0000.0c07.ac03 (default)Hello time 3 sec, hold time 10 secNext hello sent in 1.828 secsPreemption enabledActive router is localStandby router is 10.10.10.10Priority 110 (configured 120)Track object 2 state Down decrement 10Track object 3 state Up decrement 10
Configuration Examples for Enhanced Object Tracking
This section provides the following configuration examples:
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Interface IP Routing: Example
In the following example, the tracking process is configured to track the IP-routing capability of serial interface 1/0. HSRP on Ethernet interface 0/0 then registers with the tracking process to be informed of any changes to the IP-routing state of serial interface 1/0. If the IP-routing state on serial interface 1/0 goes down, the priority of the HSRP group is reduced by 10.
If both serial interfaces are operational, Router A will be the HSRP active router because it has the higher priority. However, if IP on serial interface 1/0 in Router A fails, the HSRP group priority will be reduced and Router B will take over as the active router, thus maintaining a default virtual gateway service to hosts on the 10.1.0.0 subnet.
See Figure 1 for a sample topology.
Figure 1 Topology for IP Routing Support
Router A Configuration
track 100 interface serial1/0 ip routing!interface Ethernet0/0ip address 10.1.0.21 255.255.0.0standby 1 preemptstandby 1 ip 10.1.0.1standby 1 priority 110standby 1 track 100 decrement 10Router B Configuration
track 100 interface serial1/0 ip routing!interface Ethernet0/0ip address 10.1.0.22 255.255.0.0standby 1 preemptstandby 1 ip 10.1.0.1standby 1 priority 105standby 1 track 100 decrement 10Interface Line Protocol: Example
The following example is very similar to the IP-routing example. Instead, the tracking process is configured to track the line-protocol state of serial interface 1/0. HSRP on Ethernet interface 0/0 then registers with the tracking process to be informed of any changes to the line-protocol state of serial interface 1/0. If the line protocol on serial interface 1/0 goes down, the priority of the HSRP group is reduced by 10.
Router A Configuration
track 100 interface serial1/0 line-protocol!interface Ethernet0/0ip address 10.1.0.21 255.255.0.0standby 1 preemptstandby 1 ip 10.1.0.1standby 1 priority 110standby 1 track 100 decrement 10Router B Configuration
track 100 interface serial1/0 line-protocol!interface Ethernet0/0ip address 10.1.0.22 255.255.0.0standby 1 preemptstandby 1 ip 10.1.0.1standby 1 priority 105standby 1 track 100 decrement 10IP-Route Reachability: Example
In the following example, the tracking process is configured to track the reachability of IP route 10.2.2.0/24:
Router A Configuration
track 100 ip route 10.2.2.0/24 reachability!interface Ethernet0/0ip address 10.1.1.21 255.255.255.0standby 1 preemptstandby 1 ip 10.1.1.1standby 1 priority 110standby 1 track 100 decrement 10Router B Configuration
track 100 ip route 10.2.2.0/24 reachability!interface Ethernet0/0ip address 10.1.1.22 255.255.255.0standby 1 preemptstandby 1 ip 10.1.1.1standby 1 priority 105standby 1 track 100 decrement 10IP-Route Threshold Metric: Example
In the following example, the tracking process is configured to track the threshold metric of IP route 10.2.2.0/24:
Router A Configuration
track 100 ip route 10.2.2.0/24 metric threshold!interface Ethernet0/0ip address 10.1.1.21 255.255.255.0standby 1 preemptstandby 1 ip 10.1.1.1standby 1 priority 110standby 1 track 100 decrement 10Router B Configuration
track 100 ip route 10.2.2.0/24 metric threshold!interface Ethernet0/0ip address 10.1.1.22 255.255.255.0standby 1 preemptstandby 1 ip 10.1.1.1standby 1 priority 105standby 1 track 100 decrement 10Threshold Weight for a Tracked List Configuration: Example
In the following example, three serial interfaces in tracked list 100 are configured with a threshold weight of 20 each. The down threshold is configured to 0 and the up threshold is configured to 40:
track 1 interface serial2/0 line-protocoltrack 2 interface serial2/1 line-protocoltrack 3 interface serial2/2 line-protocoltrack 100 list threshold weightobject 1 weight 20object 2 weight 20object 3 weight 20threshold weight down 0 up 40The above example means that the track-list object goes down only when all three serial interfaces go down, and only comes up again when at least two serial interfaces are up (since 20+20 >= 40). The advantage of this configuration is that it prevents the track-list object from coming up if two interfaces are down and the third interface is flapping.
Threshold Percentage for a Tracked List Configuration: Example
In the following example, four serial interfaces in track list 100 are configured for an up threshold percentage of 75:
track 1 interface serial2/0 line-protocoltrack 2 interface serial2/1 line-protocoltrack 3 interface serial2/2 line-protocoltrack 4 interface serial2/3 line-protocoltrack 100 list threshold percentageobject 1object 2object 3object 4threshold percentage up 75Boolean Expression for a Tracked List Configuration: Example
In the following example, a track list object is configured to track two serial interfaces when both serial interfaces are up and when either serial interface is down:
track 1 interface serial2/0 line-protocoltrack 2 interface serial2/1 line-protocoltrack 100 list boolean andobject 1object 2In the following example, a track list object is configured to track two serial interfaces when either serial interface is up and when both serial interfaces are down:
track 1 interface serial2/0 line-protocoltrack 2 interface serial2/1 line-protocoltrack 101 list boolean orobject 1object 2Additional References
For additional information related to the Enhanced Object Tracking feature, see the following sections:
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Related Documents
Standards
No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.
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MIBs
RFCs
No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.
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Technical Assistance
Command Reference
This section documents new and modified commands only.
New Commands
Modified Commands
debug track
To display tracking activity for tracked objects, use the debug track command in privileged EXEC mode. To turn off output, use the no form of this command.
debug track
no debug track
Syntax Description
This command has no arguments or keywords.
Command Modes
Privileged EXEC
Command History
12.2(15)T
This command was introduced.
12.3(8)T
The output was enhanced to include the track-list objects.
12.2(25)S
This command was integrated into Cisco IOS Release 12.2(25)S.
Usage Guidelines
Use this command to display activity for objects being tracked by the tracking process. These objects can be the state of IP routing, the line-protocol state of an interface, the IP-route reachability, and the IP-route threshold metric.
Examples
The following example shows that object number 100 is being tracked and that the state of IP routing on Ethernet interface 0/2 is down:
Router# debug trackFeb 26 19:56:23.247:Track:100 Adding interface objectFeb 26 19:56:23.247:Track:InitialiseFeb 26 19:56:23.247:Track:100 New interface Et0/2, ip routing DownFeb 26 19:56:23.247:Track:Starting processThe following example shows that object number 100 is being tracked and that the state of IP routing on Ethernet interface 0/2 has changed and is back up:
Router# debug trackFeb 26 19:56:41.247:Track:100 Change #2 interface Et0/2, ip routing Down->Up00:15:07:%LINK-3-UPDOWN:Interface Ethernet0/2, changed state to up00:15:08:%LINEPROTO-5-UPDOWN:Line protocol on Interface Ethernet0/2, changed state to upRelated Commands
delay (tracking)
To specify a period of time to delay communicating state changes of a tracked object, use the delay command in tracking configuration mode. To disable the delay period, use the no form of this command.
delay {up seconds [down seconds] | [up seconds] down seconds}
no delay {up seconds [down seconds] | [up seconds] down seconds}
Syntax Description
up
Time to delay the notification of an up event.
down
Time to delay the notification of a down event.
seconds
Delay value, in seconds. Range is from 0 to 180. Default is 0.
Defaults
No delay time is configured for tracking.
Command Modes
Tracking configuration
Command History
12.2(15)T
This command was introduced.
12.2(25)S
This command was integrated into Cisco IOS Release 12.2(25)S.
Usage Guidelines
This command is available to all tracked objects.
If you specify, for example, delay up 10 down 30, then if the object state changes from down to up, clients tracking that object are notified after 10 seconds. If the object state changes from up to down, then clients tracking that object are notified after 30 seconds.
Examples
In the following example, the tracking process is tracking the IP-route threshold metric. The delay period to communicate the changes of the tracked object to the client process is set to 30 seconds.
track 1 ip route 10.22.0.0/16 metric thresholdthreshold metric up 16 down 20delay down 30default (tracking)
To set the default values for a tracked list, use the default command in tracking configuration mode. To disable the defaults, use the no form of this command.
default {delay | object object-number | threshold percentage}
no default {delay | object object-number | threshold percentage}
Syntax Description
delay
Default delay value.
object
Default object for the list. The object-number argument has a valid range is from 1 to 500.
threshold percentage
Default threshold percentage.
Defaults
No default behavior or values
Command Modes
Tracking configuration
Command History
12.3(8)T
This command was introduced.
12.2(25)S
This command was integrated into Cisco IOS Release 12.2(25)S.
Examples
The following example shows how to configure a default threshold percentage:
track 3 listdefault threshold percentageRelated Commands
ip vrf (tracking)
To configure a VPN routing and forwarding (VRF) table, use the ip vrf command in tracking configuration mode. To remove a VRF table, use the no form of this command.
ip vrf vrf-name
no ip vrf vrf-name
Syntax Description
Defaults
The VRF table is not configured.
Command Modes
Global configuration
Command History
12.2(15)T
This command was introduced.
12.2(25)S
This command was integrated into Cisco IOS Release 12.2(25)S.
Usage Guidelines
This command is available for all IP-route tracked objects that are tracked by the track ip route global configuration command. Use this command to track a route that belongs to a specific VPN.
Examples
In the following example, the route associated with a VRF named VRF1 is tracked:
track 1 ip route 10.0.0.0 255.255.0.0ip vrf VRF1rd 100:1route-target both 100:1!interface e0/2no shutdownip vrf forwarding VRF1ip address 20.0.0.2 255.0.0.0Related Commands
track ip route
Tracks the state of an IP route and enters tracking configuration mode.
object (tracking)
To specify an object for a tracked list, use the object command in tracking configuration mode. To remove the object from the tracked list, use the no form of this command.
object object-number [not] [weight weight-number]
no object object-number [not] [weight weight-number]
Syntax Description
Defaults
The object is removed from the tracked list.
Command Modes
Tracking configuration
Command History
12.3(8)T
This command was introduced.
12.2(25)S
This command was integrated into Cisco IOS Release 12.2(25)S.
Examples
The following example shows two serial interfaces (objects) that are in tracked list 100. The Boolean "not" negates state of object 2 , which means when object 2 is up, the tracked list regards the object as down.
track 1 interface serial2/0 line-protocoltrack 2 interface serial2/1 line-protocoltrack 100 list boolean andobject 1object 2 notRelated Commands
show track
To display tracking information, use the show track command in privileged EXEC mode.
show track [[object-number | brief] | [interface [brief] | ip route [brief] | resolution | timers]
Syntax Description
Command Modes
Privileged EXEC
Command History
12.2(15)T
This command was introduced.
12.3(8)T
The output was enhanced to include the track-list objects.
12.2(25)S
This command was integrated into Cisco IOS Release 12.2(25)S.
Usage Guidelines
Use this command to display information about objects that are tracked by the tracking process. When no keywords are specified, information for all objects is displayed.
Examples
The following example shows information about the state of IP routing on the interface that is being tracked:
Router# show track 1Track 1Interface Ethernet0/2 ip routingIP routing is Down (no IP addr)1 change, last change 00:01:08Tracked by:HSRP Ethernet0/3 1The following example shows information about the line-protocol state on the interface that is being tracked:
Router# show track 1Track 1Interface Ethernet0/1 line-protocolLine protocol is Up1 change, last change 00:00:05Tracked by:HSRP Ethernet0/3 1The following example shows information about the reachability of a route that is being tracked:
Router# show track 1Track 1IP route 10.16.0.0 255.255.0.0 reachabilityReachability is Up (RIP)1 change, last change 00:02:04First-hop interface is Ethernet0/1Tracked by:HSRP Ethernet0/3 1The following example shows information about the threshold metric of a route that is being tracked:
Router# show track 1Track 1IP route 10.16.0.0 255.255.0.0 metric thresholdMetric threshold is Up (RIP/6/102)1 change, last change 00:00:08Metric threshold down 255 up 254First-hop interface is Ethernet0/1Tracked by:HSRP Ethernet0/3 1The following example shows the object type, the interval in which it is polled, and the time until the next poll:
Router# show track timersObject type Poll Interval Time to next pollinterface 1 expiredip route 30 29.364Table 2 describes the significant fields shown in the displays.
The following output shows that there are two objects. Object 1 has been configured with a weight of 10 "down," and object 2 has been configured with a weight of 20 "up." Object 1 is down (expressed as 0/10) and object 2 is up. The total weight of the tracked list is 20 with a maximum of 30 (expressed as 20/30). The "up" threshold is 20, so the list is "up."
Router# show trackTrack 6List threshold weightThreshold weight is Up (20/30)1 change, last change 00:00:08object 1 Down (0/10)object 2 weight 20 Up (20/30)Threshold weight down 10 up 20Tracked by:HSRP Ethernet0/3 1The following example shows information about the Boolean configuration:
Router# show trackTrack 3List boolean andBoolean AND is Down1 change, last change 00:00:08object 1 not Upobject 2 DownTracked by:HSRP Ethernet0/3 1Table 3 describes the significant fields shown in the displays.
Related Commands
standby track
To configure the Hot Standby Router Protocol (HSRP) to track an object and change the Hot Standby priority on the basis of the state of the object, use the standby track command in interface configuration mode. To remove the tracking, use the no form of this command.
Cisco IOS Release 12.2(15)T and Later Releases
standby [group-number] track object-number [decrement [priority-decrement]]
no standby [group-number] track object-number [decrement [priority-decrement]]
Cisco IOS Release 12.2(13)T and Earlier Releases
standby [group-number] track interface-type interface-number [interface-priority]
no standby [group-number] track interface-type interface-number [interface-priority]
Syntax Description
Defaults
There is no tracking.
Command Modes
Interface configuration
Command History
Usage Guidelines
This command ties the Hot Standby priority of the router to the availability of its tracked objects. Use the track interface or track ip route global configuration commands to track an interface object or an IP-route object. The HSRP client can register its interest in the tracking process by using the standby track command and take action when the object changes.
When a tracked object goes down, the Hot Standby priority decreases by 10. If an object is not tracked, its state changes do not affect the Hot Standby priority. For each object configured for Hot Standby, you can configure a separate list of objects to be tracked.
The optional priority argument specifies how much to decrement the Hot Standby priority when a tracked object goes down. When the tracked object comes back up, the priority is incremented by the same amount.
When multiple tracked objects are down, the decrements are cumulative, whether configured with priority values or not.
Use the no standby group-number track command to delete all tracking configuration for a group.
When group number 0 is used, no group number is written to NVRAM, providing backward compatibility.
The standby track command syntax prior to Cisco IOS Release 12.2(15)T is still supported. Using the older form of the command syntax will cause a tracked object to be created in the new tracking process. This tracking information can be displayed using the show track command.
Examples
In the following example, the tracking process is configured to track the IP-routing capability of serial interface 1/0. HSRP on Ethernet interface 0/0 then registers with the tracking process to be informed of any changes to the IP-routing state of serial interface 1/0. If the IP state on serial interface 1/0 goes down, the priority of the HSRP group is reduced by 10.
If both serial interfaces are operational, Router A will be the HSRP active router because it has the higher priority. However, if IP routing on serial interface 1/0 in Router A fails, the HSRP group priority will be reduced and Router B will take over as the active router, thus maintaining a default virtual gateway service to hosts on the 10.1.0.0 subnet.
Router A Configuration
track 100 interface serial1/0 ip routing!interface Ethernet0/0ip address 10.1.0.21 255.255.0.0standby 1 preemptstandby 1 ip 10.1.0.1standby 1 priority 105standby 1 track 100 decrement 10Router B Configuration
track 100 interface serial1/0 ip routing!interface Ethernet0/0ip address 10.1.0.22 255.255.0.0standby 1 preemptstandby 1 ip 10.1.0.1standby 1 priority 11standby 1 track 100 decrement 10Related Commands
threshold metric
To set a threshold metric other than the default value, use the threshold metric command in tracking configuration mode. To disable the threshold metric, use the no form of this command.
threshold metric {up number | down number}
no threshold metric {up number | down number}
Syntax Description
Defaults
No threshold is configured.
Command Modes
Tracking configuration
Command History
12.2(15)T
This command was introduced.
12.2(25)S
This command was integrated into Cisco IOS Release 12.2(25)S.
Usage Guidelines
This command is available only to IP-route threshold metric objects tracked by the track ip route metric threshold global configuration command.
The default up and down threshold values are 254 and 255, respectively. With these values, IP-route threshold tracking gives the same result as IP-route reachability tracking.
Examples
In the following example, the tracking process is tracking the IP-route threshold metric. The metric default value is changed to 16 for the up threshold and to 20 for the down threshold.
track 1 ip route 10.22.0.0/16 metric thresholdthreshold metric up 16 down 20delay down 20Related Commands
track ip route
Tracks the state of IP routing and enters tracking configuration mode.
threshold percentage
To set a threshold percentage for a tracked object in a list of objects, use the threshold percentage command in tracking configuration mode. To disable the threshold percentage, use the no form of this command.
threshold percentage {up number | down number}
no threshold percentage {up number | down number}
Syntax Description
up
Specifies the up threshold.
down
Specifies the down threshold.
number
Threshold value. Range is from 0 to 100.
Defaults
No threshold percentage is configured.
Command Modes
Tracking configuration
Command History
12.3(8)T
This command was introduced.
12.2(25)S
This command was integrated into Cisco IOS Release 12.2(25)S.
Usage Guidelines
When you configure a tracked list using the track object-number list command, there are two keywords available: boolean and threshold. If you specify the threshold keyword, you can specify either the percentage or weight keywords. If you specify the percentage keyword, then the weight keyword is unavailable. If you specify the weight keyword, then the percentage keyword is unavailable.
You should configure the "up" percentage first. The valid range is from 1 to 100. The down percentage depends on what you have configured for upe. For example, if you configure 50 percent for up, you will see a range from 0 to 49 percent for down.
Examples
In the following example, the tracked list 11 is configured to measure the threshold using an "up" percentage of 50 and a "down" percentage of 32.
track 11 list threshold percentageobject 1object 2threshold percentage up 50 down 32Related Commandse
threshold weight
Sets a threshold weight for a tracked object in a list of objects.
threshold weight
To set a threshold weight for a tracked object in a list of objects, use the threshold weight command in tracking configuration mode. To disable the threshold weight, use the no form of this command.
threshold weight {up number | down number}
no threshold weight {up number | down number}
Syntax Description
up
Specifies the up threshold.
down
Specifies the down threshold.
number
Threshold value. Range is from 1 to 255.
Defaults
No threshold weight is configured.
Command Modes
Tracking configuration
Command History
12.3(8)T
This command was introduced.
12.2(25)S
This command was integrated into Cisco IOS Release 12.2(25)S.
Usage Guidelines
When you configure a tracked list of objects using the track object-number list command, there are two keywords available: boolean and threshold. If you specify the threshold keyword, you can specify either the percentage or weight keywords. If you specify the weight keyword, then the percentage keyword is unavailable. If you specify the percentage keyword, then the weight keyword is unavailable.
You should configure the "up" weight first. The valid range is from 1 to 255. The available "down" weight depends on what you have configured for the "up" weight. For example, if you configure 25 for up, you will see a range from 0 to 24 for down.
Examples
In the following example, the tracked list 12 is configured to measure a threshold using a specified weight.
track 12 list threshold weightobject 1object 2threshold weight up 35 down 22Related Commands
threshold percentage
Sets a threshold percentage for a tracked object in a list of objects
track interface
To configure an interface to be tracked and to enter tracking configuration mode, use the track interface command in global configuration mode. To remove the tracking, use the no form of this command.
track object-number interface type number {line-protocol | ip routing}
no track object-number interface type number {line-protocol | ip routing}
Syntax Description
Defaults
No interface is tracked.
Command Modes
Global configuration
Command History
Usage Guidelines
This command reports a state value to clients. An IP-routing object is considered up when the following criteria exist:
•
•
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Interface IP routing will go down when one of the following criteria exist:
•
•
•
Tracking the IP-routing state of an interface using the track interface ip routing command can be more useful in some situations than just tracking the line-protocol state using the track interface line-protocol command, especially on interfaces for which IP addresses are negotiated. For example, on a serial interface that uses the Point-to-Point Protocol (PPP), the line protocol could be up [link control protocol (LCP) negotiated successfully], but IP could be down (IPCP negotiation failed).
The track interface ip routing command supports the tracking of an interface with an IP address acquired through any of the following methods:
•
•
•
•
Examples
In the following example, the tracking process is configured to track the IP-routing capability of serial interface 1/0:
track 1 interface serial1/0 ip routingRelated Commands
track ip route
To track the state of an IP route and to enter tracking configuration mode, use the track ip route command in global configuration mode. To remove the tracking, use the no form of this command.
track object-number ip route ip-address/prefix-length {reachability | metric threshold}
no track object-number ip route ip-address/prefix-length {reachability | metric threshold}
Syntax Description
Defaults
The route to the subnet address is not tracked.
Command Modes
Global configuration
Command History
12.2(15)T
This command was introduced.
12.2(25)S
This command was integrated into Cisco IOS Release 12.2(25)S.
Usage Guidelines
A tracked IP-route object is considered up and reachable when a routing-table entry exists for the route and the route is not inaccessible.
To provide a common interface to tracking clients, route metric values are normalized to the range of 0 to 255, where 0 is connected and 255 is inaccessible. The resulting value is compared against threshold values to determine the tracking state as follows:
•
•
The tracking process uses a per-protocol configurable resolution value to convert the real metric to the scaled metric. The metric value communicated to clients is always such that a lower metric value is better than a higher metric value.
Use the threshold metric tracking configuration command to specify a threshold metric other than the default threshold metric.
Examples
In the following example, the tracking process is configured to track the reachability of 10.22.0.0/16:
track 1 ip route 10.22.0.0/16 reachabilityIn the following example, the tracking process is configured to track the threshold metric using the default threshold metric values:
track 1 ip route 10.22.0.0/16 metric thresholdRelated Commands
show track
Displays HSRP tracking information.
threshold metric
Sets a threshold metric other than the default value.
track list
To specify a list of objects to be tracked and the thresholds to be used for comparison, use the track list command in global configuration mode. To disable the tracked list, use the no form of this command.
track object-number list {boolean {and | or}} | {threshold {weight | percentage}}
no track object-number list {boolean {and | or}} | {threshold {weight | percentage}}
Syntax Description
Defaults
The list is not tracked.
Command Modes
Global configuration
Command History
12.3(8)T
This command was introduced.
12.2(25)S
This command was integrated into Cisco IOS Release 12.2(25)S.
Examples
A track list object may be configured to track two serial interfaces when both serial interfaces are "up" and when either serial interface is "down," for example:
track 1 interface serial2/0 line-protocoltrack 2 interface serial2/1 line-protocoltrack 100 list boolean andobject 1object 2A track list object may be configured to track two serial interfaces when either serial interface is "up" and when both serial interfaces are "down," for example:
track 1 interface serial2/0 line-protocoltrack 2 interface serial2/1 line-protocoltrack 101 list boolean orobject 1object 2A track list object may be configured to track two serial interfaces when both serial interfaces are "up" and when both serial interface is "down," for example:
track 1 interface serial2/0 line-protocoltrack 2 interface serial2/1 line-protocoltrack 102 threshold weightobject 1 weight 10object 2 weight 10threshold weight up 20 down 0The configuration shown above provides some hysteresis in case one of the serial interfaces is flapping.
Related Commands
track resolution
To specify resolution parameters for a tracked object, use the track resolution command in global configuration mode. To disable this functionality, use the no form of this command.
track resolution ip route {eigrp resolution-value | isis resolution-value | ospf resolution-value | static resolution-value}
no track resolution ip route {eigrp resolution-value | isis resolution-value | ospf resolution-value | static resolution-value}
Syntax Description
Defaults
The track ip route metric resolution default values are used.
Command Modes
Global configuration
Command History
12.3(8)T
This command was introduced.
12.2(25)S
This command was integrated into Cisco IOS Release 12.2(25)S.
Usage Guidelines
The track ip route command causes tracking of a route in the routing table. If a route exists in the table, the metric value is converted into a number in the range from 0 to 255. The metric resolution for the specified routing protocol is used to do the conversion. There are default values for the metric resolution but the track resolution command can be used to change the metric resolution default values.
Examples
In the following example, the EIGRP routing protocol has a resolution value of 280.
track resolution ip route eigrp 280Related Commands
track timer
To specify the interval in which the tracking process polls the tracked object, use the track timer command in tracking configuration mode. To disable this functionality, use the no form of this command.
track timer {interface | ip route} seconds
no track timer {interface | ip route} seconds
Syntax Description
Defaults
If you do not use the track timer command to specify a polling interval, a tracked object will be tracked at the default polling interval.
Command Modes
Tracking configuration
Command History
12.2(15)T
This command was introduced.
12.2(25)S
This command was integrated into Cisco IOS Release 12.2(25)S.
Examples
In the following example, the tracking process is configured to poll the tracked interface every 3 seconds:
track timer interface 3Glossary
DHCP—Dynamic Host Configuration Protocol. DHCP is a protocol that delivers IP addresses and configuration information to network clients.
GLBP—Gateway Load Balancing Protocol. Provides automatic router backup for IP hosts that are configured with a single default gateway on an IEEE 802.3 LAN. Multiple first-hop routers on the LAN combine to offer a single virtual first-hop IP router while sharing the IP packet forwarding load. Other routers on the LAN may act as redundant (GLBP) routers that will become active if any of the existing forwarding routers fail.
HSRP—Hot Standby Router Protocol. Provides high network availability and transparent network topology changes. HSRP creates a Hot Standby router group with a lead router that services all packets sent to the Hot Standby address. The lead router is monitored by other routers in the group, and if it fails, one of these standby routers inherits the lead position and the Hot Standby group address.
IPCP—IP Control Protocol. The protocol used to establish and configure IP over PPP.
LCP—Link Control Protocol. The protocol used to establish, configure, and test data-link connections for use by PPP.
PPP—Point-to-Point Protocol. Provides router-to-router and host-to-network connections over synchronous and asynchronous circuits. PPP is most commonly used for dial-up Internet access. Its features include address notification, authentication via CHAP or PAP, support for multiple protocols, and link monitoring.
VRF—VPN routing and forwarding instance. A VRF consists of an IP routing table, a derived forwarding table, a set of interfaces that use the forwarding table, and a set of rules and routing protocols that determine what goes into the forwarding table. In general, a VRF includes the routing information that defines a customer VPN site that is attached to a provider edge router.
VRRP—Virtual Router Redundancy Protocol. Eliminates the single point of failure inherent in the static default routed environment. 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 that controls the IP addresses associated with a virtual router is called the master, and forwards packets sent to these IP addresses. The election process provides dynamic failover in the forwarding responsibility should the master become unavailable. Any of the virtual router IP addresses on a LAN can then be used as the default first-hop router by end hosts.
Note
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