Cisco Catalyst SD-WAN Policies Configuration Guide, Releases 26.x and Later

Application probe classes

Updated: April 24, 2026

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Explains how application probe classes define color, and DSCP mapping for applications in a Cisco SD-WAN network site.

A application probe class is a policy component that

defines forwarding class, color, and DSCP markings for application-aware routing probes,
determines the QoS queue for BFD echo requests at the egress tunnel port, and
controls DSCP usage and probe behavior when combined with SLA classes.

App-Probe class behavior and scope

Color and DSCP mapping are local to each Cisco SD-WAN network site, although some colors remain consistent across sites. BFD packet-loss priority is fixed to low.

When BFD packets use an SLA class, they use the same DSCP value. When BFD packets use both an SLA class and an app-probe-class, probes are sent separately for each SLA app-probe-class in a round-robin manner.

When the application route policy is applied at a site, only the colors relevant to the site are used. The maximum number of SLA class supported is platform dependent. For example, in ASR1000 series, upto 15 SLA classes are configurable. The maximum number of app-probe-class is always six across all the platforms.

Configure an application probe class

Use one of these methods to configure an application probe class

Configure app probe class using policy groups

Use these steps to configure app probe class using policy groups.

Procedure

	1.	From the Cisco SD-WAN Manager menu, choose Configuration > Policy Groups > Objects and Profiles.
	2.	From the left pane, click App Probe Class, and then click Add app probe class.
	3.	Enter the probe class name in the Probe Class Name field.
	4.	Choose the required class map from the Class Map drop-down list.
	5.	Choose the appropriate color from the Color drop-down list and enter the DSCP value.
	6.	Click + icon, to add more entries as required.
	7.	Click Save.

Application probe class configuration using CLI

Configure the application probe class and map it with the SLA class using CLI commands.

Use this example to configure an application probe class for real-time video and map it to an SLA class.

Device(config)# app-probe-class real-time-video
Device(config)# forwarding-class videofc
Device(config)# color mpls dscp 34
Device(config)# color biz-internet dscp 40
Device(config)# color lte dscp 0

Device(config)# sla-class streamsla
Device(config)# latency 20
Device(config)# loss 10
Device(config)# app-probe-class real-time-video

Configure the default DSCP value using the BFD template:

Device(config)# bfd default-dscp 50 
Device(config)# bfd color mpls 15

Configure an application probe class using classic policies

Use these steps to configure an application probe class, define its probe classes, and associate them with forwarding classes for application-aware routing.

Procedure

	1.	From the Cisco SD-WAN Manager menu, choose Configuration > Policies.
	2.	In Centralized Policy, click Add Policy. The Create Groups of Interest page appears.
	3.	Choose the list type App Probe Class from the left navigation panel to create your groups of interest.
	4.	Click New App Probe Class.
	5.	Enter the probe class name in the Probe Class Name field.
	6.	Choose the required forwarding class from the Forwarding Class drop-down list. If there are no forwarding classes, create a class from the Class Map list page under the Localized Policy Lists in the Custom Options menu. To create a forwarding class: In the Custom Options drop-down, choose Lists from the Localized Policy options. In the Define Lists window, choose the list type Class Map from the left navigation panel. Click New Class List to create a new list. Enter Class and choose the Queue from the drop-down list. Click Save.
	7.	In the Entries pane, choose the appropriate color from the Color drop-down list and enter the DSCP value. Click + sign to add more entries as required.
	8.	Click Save.

Add app-probe-class to an SLA class

Use these steps to create a new SLA class and associate it with an app probe class to enable performance monitoring based on loss, latency, and jitter criteria.

Procedure

	1.	From the left pane, select SLA Class.
	2.	Click New SLA Class List.
	3.	In the SLA Class List Name field, enter a name for the SLA class list.
	4.	Enter the required values for Loss (%), Latency (ms), and Jitter (ms).
	5.	Choose the required app probe class from the App Probe Class drop-down list.
	6.	Click Add. The new SLA Class created with loss, latency, jitter, and app probe class is added to the table.

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