SSCP Systems Security Certified PractitionerNetwork and Communications SecurityHard
A company is implementing a new voice over IP (VoIP) system and needs to ensure that voice traffic receives priority over other network traffic to maintain call quality. Which Quality of Service (QoS) mechanism is most appropriate for marking and prioritizing this time-sensitive traffic?
- AType of Service (ToS)
- BDifferentiated Services Code Point (DSCP)
- CClass of Service (CoS)
- DExplicit Congestion Notification (ECN)
Show answer & explanationAnswer & explanation
Correct answer: B. Differentiated Services Code Point (DSCP)
Differentiated Services Code Point (DSCP) is used at Layer 3 (IP header) to classify and manage network traffic by providing different levels of service. It's widely used in modern networks for QoS, including prioritizing real-time traffic like VoIP, by marking packets for preferential treatment.
Why the other options are wrong
- A. ToS is an older field in the IP header that DSCP largely superseded; while conceptually similar, DSCP offers more granular control.
- C. CoS operates at Layer 2 (Ethernet frames) and is typically used within a single LAN segment, not across an entire IP network.
- D. ECN is used for congestion control, allowing routers to signal congestion without dropping packets, but it's not primarily for traffic prioritization.
Differentiated Services Code Point (DSCP)
A 6-bit field in the IP header used to classify and manage network traffic, enabling Quality of Service (QoS) by assigning different service levels.
- Operates at Layer 3 (IP header).
- Provides granular traffic classification.
- Widely used for prioritizing real-time traffic like VoIP.
Memory trick: Quality Services Deliver Clear Prizing.