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Table Of Contents
OER Application-Aware Routing: PBR
Prerequisites for OER Application-Aware Routing: PBR
Restrictions for OER Application-Aware Routing: PBR
Information About OER Application-Aware Routing: PBR
Traffic is Filtered in a Named Extended Access List
Filtered Traffic is Policy Routed Through an OER Map
Border Routers Must be Single Hop Peers
Interim Border Router Configuration
How to Configure Application-Aware Policy Routing
Configuring Application-Aware Policy Routing
Configuring an Interim Border Router
Configuration Examples for Application-Aware Policy Routing
Moving Delay Sensitive Traffic To Links with the Lowest Delay: Example
OER Application-Aware Routing: PBR
The OER Application-Aware Routing: PBR feature introduces the capability to optimize traffic based on portions of an IP packet, other than the destination address. Independent Optimized Edge Routing (OER) policy configuration is applied to only a subset of the traffic carried by the monitored prefix. You can use this feature to apply very granular OER policy configuration based on the type of application or IP packet, without changing OER policy configuration for other traffic that is carried by the monitored prefix. The master controller uses policy-based routing (PBR) to send the subset of traffic to the external interface that conforms to the independent policy configuration.
History for the OER Application-Aware Routing: PBR Feature
Finding Support Information for Platforms and Cisco IOS Software Images
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Contents
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Prerequisites for OER Application-Aware Routing: PBR
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Prerequisites for OER Application-Aware Routing: PBR
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Restrictions for OER Application-Aware Routing: PBR
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Information About OER Application-Aware Routing: PBR
The OER Application-Aware Routing: PBR feature allows you to apply independent Optimized Edge Routing (OER) policy configuration to a subset of traffic that is carried by a monitored prefix. This feature allows you to optimize outbound traffic for specific applications based on values in the IP packet header, information other than the Layer 3 (Network) destination address.
The feature provides a very granular mechanism that allows you to define an OER policy for the monitored prefix and then apply an independent policy to only a subset of traffic carried by the monitored prefix. For example, this feature can be used to send traffic for a monitored prefix out of the network through the first available in-policy exit but then send delay sensitive application traffic, such as Telnet, out through the exit with the lowest delay characteristics.
Applications or specific types of traffic are monitored only within the context of a prefix. The prefix that carries the specific traffic must be monitored by the master controller. The monitored prefix can be learned automatically based delay or throughput characteristics or can be configured with an IP prefix list.
Traffic is Filtered in a Named Extended Access List
Independent OER policy configuration is applied to traffic that is filtered through a named extended IP access list (ACL). Only named extended ACLs are supported. The extended ACL is configured with a permit statement and then referenced in an OER map.
The extended ACL provides a very granular filter. Any IP packet header information that can be filtered through an extended ACL, can be used to define a subset of traffic that is carried by the monitored prefix. This information includes but is not limited to the following:
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For a list of IANA assigned port numbers, refer to the following document:
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For a list of IANA assigned protocol numbers, refer to the following document:
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Filtered Traffic is Policy Routed Through an OER Map
The match ip address (OER) command has been enhanced to support extended ACLs. The extended ACL is referenced in an OER map. Only a single match clause can be configured for each OER map sequence. Set clauses are configured to apply independent OER policies to matched traffic (subset of the monitored prefix). The OER policy is applied to all border routers to enforce policy routing for the application. Matched traffic is policy routed through the OER external interface that conforms to policy parameters.
Border Routers Must be Single Hop Peers
For this release of the OER Application-Aware Routing: PBR feature, the border routers must be one hop away from each other. However, if the design of your network requires the border routers to be separated by more than one hop, a Cisco router between the border routers can be configured as an interim border router. The interim border routers act as transit routers between the border routers in your network. The master controller discovers the paths between interim and standard border routers and policy routes traffic through the appropriate external interface on a standard border router.
Interim Border Router Configuration
The configuration of an interim border router is similar to standard border router configuration. There is only one exception. No external interfaces are defined in the master controller configuration for the interim border router. However, a single internal interface must be configured for the interim border router to establish connectivity with the master controller. The configuration on the interim border router is the same as with a standard border router.
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How to Configure Application-Aware Policy Routing
This section contains the following procedures:
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Configuring Application-Aware Policy Routing
This section describes the steps to configure application-aware policy routing. This section shows an example policy configuration to route delay sensitive traffic over interfaces with the lowest delay characteristics. However, any OER policy configuration can be configured for traffic that can be filtered with a permit statement in an extended IP access list.
This feature is configured on an OER master controller. The following tasks are completed in this section:
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Restrictions
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SUMMARY STEPS
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DETAILED STEPS
Examples
The following example matches Telnet traffic sourced from the 192.168.1.0/24 network and applies a policy to ensure it is sent out through exit links with that have a response time that is equal to or less than 30 milliseconds:
Router(config)# ip access-list extended TELNETRouter(config-ext-nacl)# permit tcp 192.168.1.0 0.0.0.255 any eq telnetRouter(config-ext-nacl)# exitRouter(config)# oer-map BLUERouter(config-route-map)# match ip address access-list TELNETRouter(config-route-map)# set delay threshold 30Router(config-route-map)# set resolve delay priority 1 variance 20Router(config-route-map)# endThe following example shows TCP application traffic filtered based on port 23 (Telnet):
Router# show oer master appl tcp 23 23 dst policyPrefix Appl Prot Port Port Type Policy--------------------------------------------------------------------------------10.1.1.0/24 tcp [23, 23] src 10What to Do Next
If the design of your network requires the border routers to be separated by more than one hop, a Cisco router between the border routers can be configured as an interim border router. See the next section for more information.
Configuring an Interim Border Router
This section describes the steps to configure an Interim border router. The configuration of an interim border router is similar to standard border router configuration. The physical configuration on the interim border router is the same as on a standard border router. The difference is in the configuration on the master controller. Only a single internal interface is configured. No external interface configuration is required.
SUMMARY STEPS
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DETAILED STEPS
Examples
The following configuration example configures an interim border router on a master controller:
Router(config)# key chain OERRouter(config-keychain)# key 1Router(config-keychain-key)# key-string CISCORouter(config-keychain-key)# exitRouter(config-keychain)# exitRouter(config)# oer masterRouter(config-oer-mc)# border 10.100.1.1 key-chain OERRouter(config-oer-mc-br)# interface Ethernet 0/1 internalRouter(config-oer-mc-br)# endConfiguration Examples for Application-Aware Policy Routing
This section provides the following example for the OER Application-Aware Routing: PBR feature:
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Moving Delay Sensitive Traffic To Links with the Lowest Delay: Example
Telnet traffic is delay sensitive. Long TCP delays can make Telnet sessions difficult to use. The following example matches Telnet traffic sourced from the 192.168.1.0/24 network and applies a policy to ensure it is sent out through exit links with that have a response time that is equal to or less than 30 milliseconds:
Router(config)# ip access-list extended TELNETRouter(config-ext-nacl)# permit tcp 192.168.1.0 0.0.0.255 any eq telnetRouter(config-ext-nacl)# exitRouter(config)# oer-map BLUERouter(config-route-map)# match ip address access-list TELNETRouter(config-route-map)# set delay threshold 30Router(config-route-map)# set resolve delay priority 1 variance 20Router(config-route-map)# endThe following example shows TCP application traffic filtered based on port 23 (Telnet):
Router# show oer master appl tcp 23 23 dst policyPrefix Appl Prot Port Port Type Policy--------------------------------------------------------------------------------10.1.1.0/24 tcp [23, 23] src 10Additional References
The following sections provide references related to the OER Application-Aware Routing: PBR feature:
Related Documents
Extended Access Lists —The Cisco IOS IP Application Services Configuration Guide, Release 12.4 provides information about the configuration of extended access lists.
http://www.cisco.com/univercd/cc/td/doc/product/software/ios124/124cg/hiap_c/index.htm
IP Protocol-Number Assignment—The IANA website provides a list of assigned protocol numbers.
IP Port-Number Assignment—The IANA website provides a list of assigned port numbers.
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 standards has not been modified by this feature.
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Technical Assistance
Command Reference
This section documents new and modified commands.
debug oer border pbr
To display debugging information for Policy-Based Routing (PBR) events on a border router, use the debug oer border pbr command in privileged EXEC mode. To stop the display of OER debugging information
debug oer border pbr [detail]
no debug oer border pbr [detail]
Syntax Description
Command Default
No default behavior or values
Command Modes
Privileged EXEC
Command History
Usage Guidelines
The debug oer border pbr command is used to display debugging information for the OER Application-Aware Routing: PBR feature. This command is entered on the border router.
Examples
The following example enables the display of PBR events on a border router:
Router# debug oer border pbrSep 1 12:30:22.291: OER BR PBR:Table 1 describes the significant fields shown in the display.
Table 1 debug oer border pbr Field Descriptions
OER BR PBR:
Indicates a PBR event.
Related Commands
Enables an OER process and configures a router as an OER border router or as an OER master controller.
debug oer master prefix
To display debug events related to prefix processing on an OER master controller, use the debug oer master prefix command in privileged EXEC mode. To disable the display of debug information, use the no form of this command.
debug oer master prefix [prefix | appl] [detail]
no debug oer master prefix [prefix | appl] [detail]
Syntax Description
Defaults
No default behavior or values
Command Modes
Privileged EXEC
Command History
Usage Guidelines
The debug oer master prefix command is entered on a master controller. This command displays debugging information related to prefix monitoring and processing.
Examples
The following example shows the master controller searching for the target of an active probe after the target has become unreachable.
Router# debug oer master prefixOER Master Prefix debugging is on06:01:28: OER MC PFX 10.4.9.0/24: APC last target deleted for prefix, no targetsleft assigned and running06:01:38: OER MC PFX 10.4.9.0/24: APC Attempting to probe all exits06:02:59: OER MC PFX 10.4.9.0/24: APC last target deleted for prefix, no targetsleft assigned and running06:03:08: OER MC PFX 10.4.9.0/24: APC Attempting to probe all exits06:04:29: OER MC PFX 10.4.9.0/24: APC last target deleted for prefix, no targetsleft assigned and running06:04:39: OER MC PFX 10.4.9.0/24: APC Attempting to probe all exits06:05:59: OER MC PFX 10.4.9.0/24: APC last target deleted for prefix, no targetsleft assigned and running06:06:09: OER MC PFX 10.4.9.0/24: APC Attempting to probe all exitsTable 2 describes the significant fields shown in the display.
Table 2 debug oer master prefix Field Descriptions
OER MC PFX ip-address:
Indicates debugging information for OER monitored prefixes. The ip-address identifies the prefix.
Related Commands
Enables an OER process and configures a router as an OER border router or as an OER master controller.
match ip address (OER)
To reference an extended IP access list or IP prefix as match criteria in an OER map, use the match ip address (OER) command in oer-map configuration mode. To delete the match clause entry, use the no form of this command.
match ip address {access-list name | prefix-list name}
no match ip address
Syntax Description
access-list name
Named extended access list configured with the ip access-list command.
prefix-list name
Name of a prefix list created with the ip prefix-list command.
Defaults
No default behavior or values
Command Modes
oer-map
Command History
12.3(8)T
This command was introduced.
12.4(2)T
Support for matching extended access lists was introduced in Cisco IOS Release 12.4(2)T.
Usage Guidelines
The match ip address (OER) command is entered on a master controller in oer-map configuration mode. This command is used to configure a named extended access list or IP prefix list as a match criteria in an oer-map.Only one match clause can be configured for each oer-map sequence. The access list is created with the ip access-list command. Only named extended IP access lists are supported. The IP prefix list is created with the ip prefix-list command. A prefix can be any IP network number combined with a prefix mask that specifies the prefix length.
Examples
The following example creates a prefix list named CUSTOMER. The prefix list creates a filter for the 10.4.9.0/24 network. The match ip address (OER) command configures the prefix list as match criteria in an oer-map.
Router(config)# ip prefix-list CUSTOMER permit 10.4.9.0/24Router(config)# !Router(config)# oer-map SELECT_EXIT 10Router(config-oer-map)# match ip address prefix-list CUSTOMERRouter(config-oer-map)# set mode select-exit goodThe following example creates an extended access list named FTP. The named extended access list creates a filter for FTP traffic that is sourced from the 10.1.1.0/24 network. The match ip address (OER) command configures the access list as match criteria in an oer-map. FTP traffic is policy routed to the first in-policy exit.
Router(config)# ip access-list extended FTPRouter(config-ext-nacl)# permit tcp 10.1.1.0 0.0.0.255 any eq ftpRouter(config-ext-nacl)# exitRouter(config)# oer-map SELECT_EXIT 10Router(config-oer-map)# match ip address access-list FTPRouter(config-oer-map)# set mode select-exit good
Related Commands
show oer master active-probes
To display connection and status information about active probes on an OER master controller, use the show oer master active-probes command in Privileged EXEC mode.
show oer master active-probes [appl]
Syntax Description
appl
Filters the output display active probes generated for application traffic configured with the OER Application-Aware Routing: PBR feature.
Defaults
No default behavior or values
Command Modes
Privileged EXEC
Command History
12.3(8)T
This command was introduced.
12.4(2)T
Support for the appl keyword was introduced in Cisco IOS Release 12.4(2)T.
Usage Guidelines
The show oer master active-probes command is entered on a master controller. This command is used to display the status of active probes. The output from this command displays the active probe type and destination, the border router that is the source of the active probe, the target prefixes that are used for active probing, and wether the probe was learned or configured. Entering the appl keyword filters the output to display information about applications optimized by the master controller.
Examples
The following example shows the status of configured and running active probes:
Router# show oer master active-probesOER Master Controller active-probesBorder = Border Router running this ProbeState = Un/Assigned to a PrefixPrefix = Probe is assigned to this PrefixType = Probe TypeTarget = Target AddressTPort = Target PortHow = Was the probe Learned or ConfiguredN - Not applicableThe following Probes exist:State Prefix Type Target TPort HowAssigned 10.1.1.1/32 echo 10.1.1.1 N LrndAssigned 10.1.4.0/24 echo 10.1.4.1 N LrndAssigned 10.1.2.0/24 echo 10.1.2.1 N LrndAssigned 10.1.4.0/24 udp-echo 10.1.4.1 65534 CfgdAssigned 10.1.3.0/24 echo 10.1.3.1 N CfgdAssigned 10.1.2.0/24 tcp-conn 10.1.2.1 23 CfgdThe following Probes are running:Border State Prefix Type Target TPort192.168.2.3 ACTIVE 10.1.4.0/24 udp-echo 10.1.4.1 65534172.16.1.1 ACTIVE 10.1.2.0/24 tcp-conn 10.1.2.1 23Table 3 describes the significant fields shown in the display.
Related Commands
Configures active probes to monitor an OER controlled prefixes.
Enables an OER process and configures a router as an OER border router or as an OER master controller.
show oer master appl
To display information about applications monitored and controlled by an oer master controller, use the show oer master appl command in Privileged EXEC mode.
show oer master appl [access-list name] [detail] | [tcp | udp] [protocol-number] [min-port max-port] [dst | src] [detail | policy]
Syntax Description
[]
Command Default
No default behavior or values
Command Modes
Privileged EXEC
Command History
Usage Guidelines
The show oer master appl command is entered on an OER master controller. This command is used to display information about applications that are configured for monitoring and optimization with the OER Application-Aware Routing: PBR feature.
Examples
The following example shows TCP application traffic filtered based on port 80 (HTTP):
Router# show oer master appl tcp 80 80 dst policyPrefix Appl Prot Port Port Type Policy--------------------------------------------------------------------------------10.1.0.0/16 tcp [80, 80] dst 2010.1.1.0/24 tcp [80, 80] dst 10Table 4 describes the significant fields shown in the display.
Related Commands
Enables an OER process and configures a router as an OER border router or as an OER master controller.
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