分析了DiffServ體系中四種聚集流的服務質量保證，給出了DiffServ在IPv4廣域骨干網上不能實現QoS保證的原因。在此基礎上，引進了接納控制機制，即在DiffServ體系中引進了RSVP資源預留協議，探討了基于Diffserv/RSVP體系的服務質量，得出節點路由表龐大的信息量對Diffserv/RSVP體系QoS保證有一定的影響，在制定了一種優化策略后，證明了基于Diffserv/RSVP體系的QoS是有保證的。從而得到一種具有QoS保證的隧道機制。
關 鍵 詞 計算機網絡; 區分服務; 資源預留協議; 隧道機制

Abstract The tunnel mechanism of IPv4 WAN backbone net based on DiffServ system is a primary solution to transit IPv6 from IPv4. The QoS guarantee supplied by this tunnel mechanism is analized. The reason why DiffServ fails to realize the QoS guarantee in IPv4 WAN backbone net is given. Then the controlled acceptance mechanism that RSVP is introduced in DiffServ systems is introduced, and the service quality based on Diffserv/RSVP is studied. The result shows that the huge information of route table of nodes still has certain side effect on the QoS guarantee in Diffserv/RSVP system and that QoS is guaranteed based on Diffserv/RSVP system.
Key words computer network ; Diffserv; resource reservation setup protocol; tunnel techniquem