New Training: QoS Marking Strategy Deep Dive

In this 5-video skill, CBT Nuggets trainer Jeremy Cioara covers Class of Service (CoS), Type of Service (ToS), IP Precedence, and Differentiated Services Code Point (DSCP) markings. Watch this new Cisco training.

Watch the full course: Cisco CCNP Enterprise Core

This training includes:

• 5 videos

• 43 minutes of training

You’ll learn these topics in this skill:

• Introduction – QoS Marking Strategy Deep Dive

• Marking and Layer 2 and 3

• IP Precedence vs. DSCP

• DSCP Per-Hop Behaviors

• Defining Your Trust Boundary

What is QoS Marking?

QoS Marking is when you mark fields within a data link or network layer header for the purpose of allowing QoS tools installed on other devices to classify it. Which fields you mark depend on the purpose of the marking. Also, not all marking options make sense for all LAN devices.

The most common QoS marking fields are IP Precedence and IP DSCP (Differentiated Services Code Point). The reason that they are so often used is because an IP header exists from one endpoint to another in a network.

When marking IP Precedence fields, you can use any binary value of 3 bits. The higher the number, the higher the importance in terms of QoS. With IP DSCP fields, you can use any binary value of 6 bits. Unlike with IP Precedence, though, the higher the number doesn't necessarily mean higher importance.

Other marking fields include CoS (Class of Service) and ToS (Type of Service).