Cisco Cisco ASR 5500
Mobile Video Gateway Overview
Features and Functionality ▀
MVG Administration Guide, StarOS Release 17 ▄
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Platform Requirements
In 12.2 and 12.3 releases, the Video Pacing feature is qualified to run on the Cisco ASR 5000 chassis for PSC2 and
PSC3 integrated with GGSN, P-GW, SAE-GW (if MVG is running on P-GW), HA, and IPSG products. To use this
feature in a combination of GGSN, P-GW, and HA products, MVG should run on GGSN or P-GW.
PSC3 integrated with GGSN, P-GW, SAE-GW (if MVG is running on P-GW), HA, and IPSG products. To use this
feature in a combination of GGSN, P-GW, and HA products, MVG should run on GGSN or P-GW.
In 14.0 and later releases, in addition to the existing ASR 5000 chassis and its supported products, the Video Pacing
feature is also qualified to run on the ASR 5500 chassis integrated with GGSN, P-GW, SAE-GW (if MVG is running on
P-GW), and HA products. To use this feature in a combination of GGSN, P-GW, and HA products, MVG should run on
GGSN or P-GW.
feature is also qualified to run on the ASR 5500 chassis integrated with GGSN, P-GW, SAE-GW (if MVG is running on
P-GW), and HA products. To use this feature in a combination of GGSN, P-GW, and HA products, MVG should run on
GGSN or P-GW.
Video Pacing Operation
The video pacing feature operates as follows:
Assume a video-encoding bit rate R and a video playback start time of 0. At time t, the subscriber UE needs to receive
Rt bytes of video content just in time for smooth playback. To address fluctuations over the wireless channel, assume
that a video buffer is kept on the subscriber UE to accommodate these fluctuations. Assume this buffer size is the
standard burst size b.
Rt bytes of video content just in time for smooth playback. To address fluctuations over the wireless channel, assume
that a video buffer is kept on the subscriber UE to accommodate these fluctuations. Assume this buffer size is the
standard burst size b.
Because many software media players do not begin playback until a certain amount of video data has been buffered, the
video pacing feature allows an initial burst of data, so in addition to the standard burst size b, assume an initial burst size
B. This initial burst size is configured based on time duration (as t seconds of video data) and calculated for each video
flow based on the determined video bit rate. The video pacing feature allows this initial burst just once, before the video
begins playing.
video pacing feature allows an initial burst of data, so in addition to the standard burst size b, assume an initial burst size
B. This initial burst size is configured based on time duration (as t seconds of video data) and calculated for each video
flow based on the determined video bit rate. The video pacing feature allows this initial burst just once, before the video
begins playing.
The video pacing feature employs a token bucket algorithm to enforce the permitted video data bytes. When a video
download begins, for any given time t, the token bucket algorithm disallows more than (Rt + B + b) data bytes, which is
the maximum allowed data bytes. After the initial burst B is completed, the video pacing feature disallows more than
(Rt + b) data bytes, and the optimal “just in time” video download rate is achieved.
download begins, for any given time t, the token bucket algorithm disallows more than (Rt + B + b) data bytes, which is
the maximum allowed data bytes. After the initial burst B is completed, the video pacing feature disallows more than
(Rt + b) data bytes, and the optimal “just in time” video download rate is achieved.
The following figures show video pacing during good and bad channel conditions.