The document discusses techniques for managing variable bitrate (VBR) video streams over networks. It notes that VBR video has bursty and unpredictable bitrates due to factors like encoding and scene changes. Three approaches are described: 1) provisioning for peak rates, wasting bandwidth much of the time, 2) modeling traffic as an effective bandwidth, 3) using prior knowledge of video content to precompute a transmission schedule minimizing bitrate and buffer overflows/underflows. Bandwidth smoothing algorithms aim to reduce peak rates by transmitting frames in advance of bursts while minimizing changes to transmission rates and buffer usage. Algorithms like MCBA and MVBA select trajectories to smoothly transmit frames within client buffer bounds.