What benefit of Diffserv?
Diffserv allows us to support multiple classes of traffic with different under- or over-provisioning ratios per class of service
e.g. 150Mbps of VoIP and 1.5Gbps of data between two POPs
=> 150Mbps of VoIP traffic with 2x over- provisioning = 300Mbps – assuming WFQ assuming a PQ mechanism only 150Mbps need be provisioned]
=> 1.5Gbps of data traffic with 1.2x over-provisioning = 1.8Gbps
=> hence 2.1Gbps of bandwidth required which can be supported with a single STM16/OC48 link
=> saving 1x STM16/OC48