Performance Routing Traceroute Reporting

Cisco IOS PfR supports standard syslog functions. The notice level of syslog is enabled by default. System logging is enabled and configured in Cisco IOS software under global configuration mode. The logging(PfR) command in PfR master controller or PfR border router configuration mode is used only to enable or disable system logging under PfR. PfR system logging supports the following message types:

• Error Messages--These messages indicate PfR operational failures and communication problems that can impact normal PfR operation.
• Debug Messages--These messages are used to monitor detailed PfR operations to diagnose operational or software problems.
• Notification Messages--These messages indicate that PfR is performing a normal operation.
• Warning Messages--These messages indicate that PfR is functioning properly but an event outside of PfR may be impacting normal PfR operation.

To modify system, terminal, destination, and other system global logging parameters, use the logging commands in global configuration mode. For more information about global system logging configuration, see to the "Troubleshooting, Logging, and Fault Management" section of the Cisco IOS Network Management Configuration Guide .

Although PfR provides the ability to diagnose issues using syslog and debug command-line interface (CLI) commands, support for traceroute reporting was introduced in the OER Support for Cost-Based Optimization and Traceoute Reporting feature. Using traceroute reporting, PfR reports traffic class performance by determining the delay on a hop-by-hop basis using traceroute probes.

Prior to traceroute reporting there was no method for measuring the delay per hop for situations such as an unexpected round trip delay value being reported for a traffic class on an exit link. PfR uses UDP traceroutes to collect per-hop delay statistics. A traceroute is defined as tracing the route to the device with the given IP address or the hostname and is useful in detecting the location of a problem that exists in the path to the device. Although traditional UDP-based traceroutes are used by default, PfR can be configured to send TCP SYN packets to specific ports that may be permitted through a firewall.

Traceroute reporting is configured on the master controller. Traceroute probes are sourced from the border router exit. This feature allows you to monitor traffic class performance on a hop-by-hop basis. When traceroute reporting is enabled, the autonomous system number, the IP address, and delay measurements are gathered for each hop from the probe source to the target prefix. By default, traceroute probes are sent only when the traffic class goes OOP. TCP-based traceroutes can be configured manually and the time interval between traceroute probes can be modified. By default, per-hop delay reporting is not enabled.

Traceroute probes are configured using the following methods:

• Periodic--A traceroute probe is triggered for each new probe cycle. The probe is sourced from the current exit of the traffic class when the option to probe only one exit is selected. If the option to probe all exits is selected, the traceroute probe is sourced from all available exits.
• Policy based--A traceroute probe is triggered automatically when a traffic class goes into an out-of-policy state. Traceroute reporting can be enabled for all traffic classes specified in the match clause of an PfR map. Policy based traceroute reporting stops when the traffic class returns to an in-policy state.
• On demand--A trace route probe can be triggered on an on demand basis when periodic traceroute reporting is not required, or the per-hop statistics are not required for all paths. Using optional keywords and arguments of the show pfr master prefix command, you can start traceroute reporting for a specific traffic class on a specific path, or all paths.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    pfr master

4.    traceroute probe-delay milliseconds

5.    exit

6.    pfr-map map-name sequence-number

7.    match pfr learn {delay | throughput}

8.    set traceroute reporting [policy {delay | loss | unreachable}]

9.    end

10.    show pfr master prefix [detail | learned [delay | throughput] | prefix [detail | policy | traceroute [exit-id | border-address | current] [now]]]

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	pfr master Example: Router(config)# pfr master	Enters PfR master controller configuration mode to configure a router as a master controller and to configure global operations and policies.
Step 4	traceroute probe-delay milliseconds Example: Router(config-pfr-mc)# traceroute probe-delay 500	Sets the time interval between traceroute probe cycles. The default time interval between traceroute probes is 1000 milliseconds. The example sets the probe interval to a 500 milliseconds.
Step 5	exit Example: Router(config-pfr-mc)# exit	Exits PfR master controller configuration mode, and returns to global configuration mode.
Step 6	pfr-map map-name sequence-number Example: Router(config)# pfr-map TRACEROUTE 10	Enters PfR map configuration mode to configure a PfR map to apply policies to selected IP prefixes. Only one match clause can be configured for each PfR map sequence. The example creates a PfR map named TRACEROUTE.
Step 7	match pfr learn {delay | throughput} Example: Router(config-pfr-map)# match pfr learn delay	Creates a match clause entry in a PfR map to match learned prefixes. Can be configured to learn prefixes based on highest delay or highest outbound throughput. Only a single match clause can be configured for each PfR map sequence. The example creates a match clause entry that matches traffic learned based on highest delay.
Step 8	set traceroute reporting [policy {delay | loss | unreachable}] Example: Router(config-pfr-map)# set traceroute reporting	Enables traceroute reporting. Monitored prefixes must be included in a PfR map. These can be learned or manually selected prefixes. Entering this command with no keywords enables continuous monitoring. Entering this command with the policy keyword enables policy-based trace route reporting.
Step 9	end Example: Router(config-pfr-map)# end	Exits PfR master controller configuration mode, and returns to privileged EXEC mode.
Step 10	show pfr master prefix [detail | learned [delay | throughput] | prefix [detail | policy | traceroute [exit-id | border-address | current] [now]]] Example: Router# show pfr master prefix 10.5.5.5 traceroute now	Displays the status of monitored prefixes. An on-demand traceroute probe is initiated by entering the current and now keywords. The current keyword displays the results of the most recent traceroute probe for the current exit. Traceroute probe results can be displayed for the specified border router exit by entering the exit-id or border-addressargument. The example initiates an on-demand traceroute probe for the 10.5.5.55 prefix.