Feng Gang National Laboratory of Communication,UESTC Aug 2017 Ver 1.4 Essential need:Quality of Service ·Quality of service? Assured bandwidth from end-to-end (e.g.8Kbps for voice), communication privacy, minimal round trip time for packet delivery,Delay jitter regularity of the data flow, etc. ·Why IP QoS2 - Application is slow!(not enough BANDWIDTH) Video broadcast occasionally stalls!(DELAy temporarily increases-JITTER) - Phone calls over IP are no better than over satellite!(too much DELAY) Phone calls have really bad voice quality!(too many phone calls- PACKET DROPPS) 2616009:Network Traffic Engineering 1:Overview Page.52616009: Network Traffic Engineering Feng Gang National Laboratory of Communication, UESTC Aug 2017 Ver 1.4 1: Overview Page.5 Essential need: Quality of Service • Quality of service? - Assured bandwidth from end-to-end (e.g. 8Kbps for voice), - communication privacy, - minimal round trip time for packet delivery, Delay jitter - regularity of the data flow, - etc. • Why IP QoS? - Application is slow! (not enough BANDWIDTH) - Video broadcast occasionally stalls! (DELAY temporarily increases – JITTER) - Phone calls over IP are no better than over satellite! (too much DELAY) - Phone calls have really bad voice quality! (too many phone calls – PACKET DROPPS) -