What are DSCP Tags?

DSCP (Differentiated Services Code Point) tags are part of the IP header used to indicate the priority or Quality of Service (QoS) level for network traffic. DSCP tags are 6-bit values that help classify and prioritize packets for specific handling, such as low-latency or high-priority treatment, in networking devices like routers and switches. The DSCP value determines the level of service a packet receives in terms of network congestion management, traffic prioritization, and packet forwarding. DSCP tags are commonly used in voice, video, and critical data applications infrastructure to ensure smooth performance by minimizing delays and packet loss. By marking packets with specific DSCP values, network devices can better handle traffic based on its importance or urgency.

In DSCP, the 6-bit field is used to assign a priority level and per-hop behavior (PHB) for each packet. While 0-7 can indicate priority levels, the actual DSCP values are mapped to these priority levels using specific code points.

Here is an explanation of the EF, AF, CS, and BE categories in DSCP (Differentiated Services Code Point):

• EF (Expedited Forwarding): Used for real-time, low-latency traffic such as Voice over IP (VoIP) and video conferencing. This category prioritizes these time-sensitive packets to ensure minimal delays and packet loss.
• AF (Assured Forwarding): Designed for data that requires assured delivery, with different levels of priority and drop precedence. It ensures that traffic is reliably delivered, but with varying levels of importance.
• CS (Class Selector): Used for backward compatibility with older IP precedence fields. It is based on the first 3 bits of the DSCP field, which define traffic classes.
• BE (Best Effort): Represents default, lowest-priority traffic in the network. It is used for non-time-sensitive traffic, where delivery speed and reliability are not critical.

Content created by Mike Day