Full form: Differentiated Services Code Point
Also known as: Differentiated Services Code Point, DiffServ
Quick Definition
A 6-bit field in the IP header used to mark packets for QoS treatment.
DSCP uses 6 bits of the IP header's Differentiated Services (DS) field to mark packets with a traffic class. Common DSCP values: EF (Expedited Forwarding, 46) for voice, AF (Assured Forwarding) for video/important data, and CS (Class Selector) for backward compatibility. Network devices use the DSCP marking to apply queuing, scheduling, and drop policies. DSCP markings are preserved end-to-end across IP networks.
DSCP operates at Layer 3 (IP header). CoS operates at Layer 2 (Ethernet 802.1Q header). When a frame leaves a trunk, CoS may be re-marked or removed. DSCP is more persistent because it travels in the IP header.
DSCP uses 6 bits of the IP header's Differentiated Services (DS) field to mark packets with a traffic class. Common DSCP values: EF (Expedited Forwarding, 46) for voice, AF (Assured Forwarding) for video/important data, and CS (Class Selector) for backward compatibility. Network devices use the DSCP marking to apply queuing, scheduling, and drop policies. DSCP markings are preserved end-to-end across IP networks.
DSCP operates at Layer 3 (IP header). CoS operates at Layer 2 (Ethernet 802.1Q header). When a frame leaves a trunk, CoS may be re-marked or removed. DSCP is more persistent because it travels in the IP header.
DSCP falls under the IP Services domain of the 200-301 exam. Understanding it in context with related terms like qos and cos is essential for answering scenario-based questions correctly.