Differentiated Services Code Point Downstream

Differentiated Services Code Point (DSCP) is a packet header value marking that can be used to request priority traffic.

Information About Differentiated Services Code Point Downstream Marking

From Cisco IOS XE Amsterdam 17.3.x and later, Cisco cBR-8 Converged Broadband Router conforms to DOCSIS service’s priority to drive traffic by high queue or low queue with various Differentiated Services Code Point Downstream (DSCP) marking. The following changes would apply:

  • In high queue, L2TP traffic will be set to DSCP 40.

  • In low queue, L2TP traffic will be set to DSCP 0.

  • For the traffic with priority greater than or equal to the threshold, the L2TP packet’s DSCP will be changed to CS5(40).

You might see the following message when you change the threshold: 


Router# cable rphy flow downstream 3
High flow queue congestion may cause packets drop or jitter or latency is unexpectedly increased. To avoid this, suggest the traffic in high queue less than 60% of full bandwidth per line-card!
This change will take effect after modem reset and online again.

We recommend that you configure the traffic for less than 60% of full bandwidth per linecard in high-flow queue. The high-flow queue is designed for high priority traffic, and without the recommended configuration it may cause unexpected packet drop, jitter, or latency in high flow queue.

Feature Information for Differentiated Services Code Point Downstream Marking

Use Cisco Feature Navigator to find information about the platform support and software image support. Cisco Feature Navigator enables you to determine which software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to the https://cfnng.cisco.com/ link. An account on the Cisco.com page is not required.


Note

The following table lists the software release in which a given feature is introduced. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Table 1. Feature Information for Differentiated Services Code Point Downstream Marking

Feature Name

Releases

Feature Information

Differentiated Services Code Point Downstream Marking

Cisco IOS XE Gibraltar 17.3.1w

This feature was introduced on the Cisco cBR Converged Broadband Router.