Differentiated Services (DiffServ) provides QoS through per-hop behaviors. Routers treat packets based on DSCP marking. No signaling required.
DiffServ architecture:
- Edge devices classify and mark
- Core routers trust markings
- No reservation state
- Scalable to any size
Per-Hop Behaviors:
- EF: Low latency for voice
- AF: classes with drop precedences
- Default: Best effort
Advantages: No per-flow state. Scales to millions of flows. Simple core, intelligent edge.
Limitation: No absolute guarantees. Too much EF traffic degrades quality.