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Table Of Contents
PBR Support for Multiple Tracking Options
Information About PBR Support for Multiple Tracking Options
PBR Support for Multiple Tracking Options Feature Design
How to Configure PBR Support for Multiple Tracking Options
Configuration Examples for PBR Support for Multiple Tracking Options
Feature Information for PBR Support for Multiple Tracking Options
PBR Support for Multiple Tracking Options
First Published: November 3, 2003Last Updated: September 29, 2008The PBR Support for Multiple Tracking Options feature extends the capabilities of object tracking using Cisco Discovery Protocol (CDP) to allow the policy-based routing (PBR) process to verify object availability by using additional methods. The verification method can be an Internet Control Message Protocol (ICMP) ping, a User Datagram Protocol (UDP) ping, or an HTTP GET request.
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the "Feature Information for PBR Support for Multiple Tracking Options" section.
Use Cisco Feature Navigator to find information about platform support and Cisco IOS and Catalyst OS software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Contents
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Information About PBR Support for Multiple Tracking Options
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Information About PBR Support for Multiple Tracking Options
To configure the PBR Support for Multiple Tracking Options feature, you should understand the following concepts:
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Object Tracking
Object tracking is an independent process that monitors objects such as the following:
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Clients such as Hot Standby Router Protocol (HSRP), Virtual Router Redundancy Protocol (VRRP), Gateway Load Balancing Protocol (GLBP), and (with this feature) PBR can register their interest in specific, tracked objects and then take action when the state of the objects changes.
PBR Support for Multiple Tracking Options Feature Design
The PBR Support for Multiple Tracking Options feature gives PBR access to all the objects that are available through the tracking process. The tracking process provides the ability to track individual objects—such as ICMP ping reachability, routing adjacency, an application running on a remote device, a route in the Routing Information Base (RIB)—or to track the state of an interface line protocol.
Object tracking functions in the following manner. PBR will inform the tracking process that a certain object should be tracked. The tracking process will in turn notify PBR when the state of that object changes.
How to Configure PBR Support for Multiple Tracking Options
The tasks in this section are divided according to the Cisco IOS release that you are running because Cisco IOS Release 12.3(14)T introduced new syntax for IP Service Level Agreements (SLAs). To use this feature, you must be running Cisco IOS Release 12.3(4)T, 12.2(25)S, or a later release. This section contains the following tasks:
Configuring PBR Support for Multiple Tracking Options in Cisco IOS Release 12.3(11)T, 12.2(25)S, and Earlier Releases
Perform this task to configure PBR support for multiple tracking options. In this task, a route map is created and configured to verify the reachability of the tracked object.
Prerequisites
This task requires the networking device to be running Cisco IOS Release 12.3(11)T, 12.2(25)S, or prior releases.
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
rtr operation-number
Example:Router(config)# rtr 1
Enters SAA RTR configuration mode and configures an SAA operation.
Step 4
type echo protocol protocol-type target [source-ipaddr ip-address]
Example:Router(config-rtr)# type echo protocol ipicmpecho 10.1.1.10
Configures an SAA end-to-end echo response time probe operation.
Step 5
exit
Example:Router(config-rtr)# exit
Exits SAA RTR configuration mode and returns the router to global configuration mode.
Step 6
rtr schedule operation-number [life {forever | seconds}] [start-time {hh:mm[:ss] [month day | day month] | pending | now | after hh:mm:ss}] [ageout seconds]
Example:Router(config)# rtr schedule 1 life forever start-time now
Configures the time parameters for the SAA operation.
Step 7
track object-number rtr entry-number [reachability]
Example:Router(config)# track 123 rtr 1 reachability
Tracks the reachability of a Response Time Reporter (RTR) object and enters tracking configuration mode.
Step 8
delay {up seconds [down seconds] | [up seconds] down seconds}
Example:Router(config-track)# delay up 60 down 30
(Optional) Specifies a period of time (in seconds) to delay communicating state changes of a tracked object.
Step 9
exit
Example:Router(config-track)# exit
Exits tracking configuration mode and returns the router to global configuration mode.
Step 10
interface type number
Example:Router(config)# interface ethernet 0
Specifies an interface type and number and enters interface configuration mode.
Step 11
ip address ip-address mask [secondary]
Example:Router(config-if)# ip address 10.1.1.11 255.0.0.0
Specifies a primary or secondary IP address for an interface.
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Step 12
ip policy route-map map-tag
Example:Router(config-if)# ip policy route-map alpha
Enables policy routing and identifies a route map to be used for policy routing.
Step 13
exit
Example:Router(config-if)# exit
Exits interface configuration mode and returns the router to global configuration mode.
Step 14
route-map map-tag [permit | deny] [sequence-number]
Example:Router(config)# route-map alpha
Specifies a route map and enters route-map configuration mode.
Step 15
set ip next-hop verify-availability [next-hop-address sequence track object]
Example:Router(config-route-map)# set ip next-hop verify-availability 10.1.1.1 10 track 123
Configures the route map to verify the reachability of the tracked object.
Step 16
end
Example:Router(config-route-map)# end
Exits route-map configuration mode and returns the router to privileged EXEC mode.
Configuring PBR Support for Multiple Tracking Options in Cisco IOS Release 12.3(14)T, 12.2(33)SXH, and Later Releases
Perform this task to configure PBR support for multiple tracking options. In this task, a route map is created and configured to verify the reachability of the tracked object.
Prerequisites
This task requires the networking device to be running Cisco IOS Release 12.3(14)T, 12.2(33)SXH, or a later release.
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
ip sla monitor operation-number
Example:Router(config)# ip sla monitor 1
Starts a Cisco IOS IP Service Level Agreement (SLA) operation configuration and enters IP SLA monitor configuration mode.
Step 4
type echo protocol ipIcmpEcho {destination-ip-address | destination-hostname} [source-ipaddr {ip-address | hostname} | source-interface interface-name]
Example:Router(config-sla-monitor)# type echo protocol ipIcmpEcho 10.1.1.1
Configures an IP SLA Internet Control Message Protocol (ICMP) echo probe operation.
Step 5
exit
Example:Router(config-sla-monitor)# exit
Exits IP SLA monitor configuration mode and returns the router to global configuration mode.
Step 6
ip sla monitor schedule operation-number [life {forever | seconds}] [start-time {hh:mm[:ss] [month day | day month] | pending | now | after hh:mm:ss}] [ageout seconds] [recurring]
Example:Router(config)# ip sla monitor schedule 1 life forever start-time now
Configures the scheduling parameters for a single Cisco IOS IP SLA operation.
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Step 7
track object-number rtr entry-number [reachability | state]
Example:Router(config)# track 123 rtr 1 reachability
Tracks the reachability of a Response Time Reporter (RTR) object and enters tracking configuration mode.
Step 8
delay {up seconds [down seconds] | [up seconds] down seconds}
Example:Router(config-track)# delay up 60 down 30
(Optional) Specifies a period of time, in seconds, to delay communicating state changes of a tracked object.
Step 9
exit
Example:Router(config-track)# exit
Exits tracking configuration mode and returns the router to global configuration mode.
Step 10
interface type number
Example:Router(config)# interface serial 2/0
Specifies an interface type and number and enters interface configuration mode.
Step 11
ip address ip-address mask [secondary]
Example:Router(config-if)# ip address 192.168.1.1 255.255.255.0
Specifies a primary or secondary IP address for an interface.
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Step 12
ip policy route-map map-tag
Example:Router(config-if)# ip policy route-map alpha
Enables policy routing and identifies a route map to be used for policy routing.
Step 13
exit
Example:Router(config-if)# exit
Exits interface configuration mode and returns the router to global configuration mode.
Step 14
route-map map-tag [permit | deny] [sequence-number]
Example:Router(config)# route-map alpha
Specifies a route map and enters route-map configuration mode.
Step 15
set ip next-hop verify-availability [next-hop-address sequence track object]
Example:Router(config-route-map)# set ip next-hop verify-availability 10.1.1.1 10 track 123
Configures the route map to verify the reachability of the tracked object.
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Step 16
end
Example:Router(config-route-map)# end
Exits route-map configuration mode and returns the router to privileged EXEC mode.
Step 17
show track object-number
Example:Router# show track 123
(Optional) Displays tracking information.
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Step 18
show route-map [map-name | all | dynamic]
Example:Router# show route-map alpha
(Optional) Displays route map information.
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Examples
The following output from the show track command shows that the tracked object 123 is reachable.
Router# show track 123Track 123Response Time Reporter 1 reachabilityReachability is Up2 changes, last change 00:00:33Delay up 60 secs, down 30 secsLatest operation return code: OKLatest RTT (millisecs) 20Tracked by:ROUTE-MAP 0The following output from the show route-map command shows information about the route map named alpha that was configured in the task.
Router# show route-map alpharoute-map alpha, permit, sequence 10Match clauses:Set clauses:ip next-hop verify-availability 10.1.1.1 10 track 123 [up]Policy routing matches: 0 packets, 0 bytesConfiguration Examples for PBR Support for Multiple Tracking Options
This section provides the following configuration examples:
Configuring PBR Support for Multiple Tracking Options in Cisco IOS Release 12.3(11)T, 12.2(25)S, and Earlier Releases: Example
In the following example, object tracking is configured for PBR on routers that are running Cisco IOS Release 12.3(11)T, 12.2(25)S, or earlier releases.
The configured policy is that packets received on Ethernet interface 0, should be forwarded to 10.1.1.1 only if that device is reachable (responding to pings). If 10.1.1.1 is not up, then the packets should be forwarded to 10.2.2.2. If 10.2.2.2 is also not reachable, then the policy routing fails and the packets are routed according to the routing table.
Two Response Time Reporters (RTRs) are configured to ping the remote devices. The RTRs are then tracked. Policy routing will monitor the state of the tracked RTRs and make forwarding decisions based on their state.
! Define and start the RTRs.rtr 1type echo protocol ipicmpecho 10.1.1.1rtr schedule 1 start-time now life forever!rtr 2type echo protocol ipicmpecho 10.2.2.2rtr schedule 2 start-time now life forever!! Track the RTRs.track 123 rtr 1 reachabilitytrack 124 rtr 2 reachability!! Enable policy routing on the incoming interface.interface ethernet 0ip address 10.4.4.4 255.255.255.0ip policy route-map beta!! 10.1.1.1 is via this interface.interface ethernet 1ip address 10.1.1.254 255.255.255.0!! 10.2.2.2 is via this interface.interface ethernet 2ip address 10.2.2.254 255.255.255.0!! Define a route map to set the next-hop depending on the state of the tracked RTRs.route-map betaset ip next-hop verify-availability 10.1.1.1 10 track 123set ip next-hop verify-availability 10.2.2.2 20 track 124Configuring PBR Support for Multiple Tracking Options in Cisco IOS Release 12.3(14)T, 12.2(33)SXH, and Later Releases: Example
In the following example, object tracking is configured for PBR on routers running Cisco IOS Release 12.3(14)T, 12.2(33)SXH, and later releases.
The configured policy is that packets received on Ethernet interface 0, should be forwarded to 10.1.1.1 only if that device is reachable (responding to pings). If 10.1.1.1 is not up, then the packets should be forwarded to 10.2.2.2. If 10.2.2.2 is also not reachable, then the policy routing fails and the packets are routed according to the routing table.
Two RTRs are configured to ping the remote devices. The RTRs are then tracked. Policy routing will monitor the state of the tracked RTRs and make forwarding decisions based on their state.
! Define and start the RTRs.ip sla monitor 1type echo protocol ipicmpecho 10.1.1.1ip sla monitor schedule 1 start-time now life forever!ip sla monitor 2type echo protocol ipicmpecho 10.2.2.2ip sla monitor schedule 2 start-time now life forever!! Track the RTRs.track 123 rtr 1 reachabilitytrack 124 rtr 2 reachability!! Enable policy routing on the incoming interface.interface ethernet 0ip address 10.4.4.4 255.255.255.0ip policy route-map beta!! 10.1.1.1 is via this interface.interface ethernet 1ip address 10.1.1.254 255.255.255.0!! 10.2.2.2 is via this interface.interface ethernet 2ip address 10.2.2.254 255.255.255.0!! Define a route map to set the next-hop depending on the state of the tracked RTRs.route-map betaset ip next-hop verify-availability 10.1.1.1 10 track 123set ip next-hop verify-availability 10.2.2.2 20 track 124Additional References
The following sections provide references related to the PBR Support for Multiple Tracking Options feature.
Related Documents
Object tracking within Cisco IOS software
Configuring Enhanced Object Tracking" chapter of the Cisco IOS IP Application Services Configuration Guide
Configuring IP addresses
"Configuring IPv4 Addresses" chapter of the Cisco IOS IP Addressing Services Configuration Guide
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
The following commands are introduced or modified in the feature or features documented in this module. For information about these commands, see the Cisco IOS IP Routing: Protocol-Independent Command Reference. For information about all Cisco IOS commands, use the Command Lookup Tool at http://tools.cisco.com/Support/CLILookup or the Cisco IOS Master Command List, All Releases, at http://www.cisco.com/en/US/docs/ios/mcl/allreleasemcl/all_book.html.
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Feature Information for PBR Support for Multiple Tracking Options
Table 1 lists the release history for this feature.
Not all commands may be available in your Cisco IOS software release. For release information about a specific command, see the command reference documentation.
Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS and Catalyst OS software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://tools.cisco.com/ITDIT/CFN/jsp/index.jsp. An account on Cisco.com is not required.
Note
Cisco and the Cisco Logo are trademarks of Cisco Systems, Inc. and/or its affiliates in the U.S. and other countries. A listing of Cisco's trademarks can be found at www.cisco.com/go/trademarks. Third party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1005R)
Any Internet Protocol (IP) addresses used in this document are not intended to be actual addresses. Any examples, command display output, and figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses in illustrative content is unintentional and coincidental.
© 2003-2008 Cisco Systems, Inc. All rights reserved.
