Meaning
Traffic classes defined within the Differentiated Services field of an IP header prioritize low-latency and low-jitter delivery for sensitive data packets. Network routers treat packets marked with this specific code as a high-priority stream that should be forwarded with minimal delay. Configuration of dscp expedited forwarding ensures that these packets bypass the standard best-effort queues and move to the front of the transmission line.
Queue Priority
High-priority traffic is the standard way to ensure that voice and video traffic remain clear and synchronized during periods of network congestion. When dscp expedited forwarding is enabled, the router allocates a specific queue that is serviced before other traffic types. This mechanism provides a capability for near-constant latency even when the physical link is saturated with lower-priority data.
Bandwidth Reservation
Strict policing of the amount of high-priority traffic is required to prevent it from starving other services. If the volume of packets using dscp expedited forwarding exceeds a set limit, the router will drop the excess data to protect the rest of the network. This balance ensures that critical timing data arrives on schedule while maintaining overall system stability.
Jitter Management
Consistency in packet arrival times is achieved by minimizing the time each packet spends waiting in a buffer. Reliable delivery depends on the hardware being able to process these priority tags at line speed without adding software overhead.
