7. References

Background & motivation Future Internet expected to support variety of services Voice and video communications induce far more stringent QoS requirements than typical data applications Integration of heterogeneous services raises need for dif-ferentiated QoS Packet scheduling provides natural mechanism to achieve differentiated QoS Scheduling mechanisms should be able to cope with adver-sarial or erratic traffic characteristics 2 Packet scheduling may be implemented at various levels • Individual traffic flows (e.g. IntServ) • Aggregate traffic flows / service classes (e.g. DiffServ: Expedited Forw. (EF), Assured Forw. (AF), BE) Involves trade-off between implementation complexity and degree of service differentiation • For scalability reasons, packet scheduling at granularity level of individual flows in core is viewed as impractical • Packet scheduling at aggregate level does not provide strict guarantees to individual flows 3 Packet scheduling may be implemented at various levels • Individual traffic flows (e.g. IntServ) • Aggregate traffic flows / service classes (e.g. DiffServ