Set up traffic shaping

If you're multicasting to set-top boxes that have 10/100 Mbps interfaces on the same Gigabit Ethernet and you notice frames are dropping, you can limit the bandwidth of the stream using traffic shaping to adapt for the lower bandwidth set-top boxes. Only multicast streams support traffic shaping: MPEG-TS USP, MPEG-TS RTP/UDP, and RTP/UDP.

If traffic shaping was previously setup using the API, we recommend switching to this method of setting traffic shaping using the Admin panel. If traffic shaping is currently setup using Pearl-2's API, see the Technical Notes for your Pearl-2 model for instructions. They're available from the product resources page on the Epiphan.com website.

When traffic shaping is enabled, the default bitrate limit is set to auto. In auto mode, the bitrate is limited to the sum of the channel's configured bitrate plus 4 Mbps and is adjusted to fit within the range of 4 Mbps minimum to 95 Mbps maximum.

You can also set a bitrate limit for the maximum amount of bandwidth that gets streamed using the Admin panel when traffic shaping is enabled. When you do, the streamed video won't exceed the maximum bitrate you set. The valid bandwidth limit bitrate range is 4 Mbps to 95 Mbps. We recommend that you set the bitrate to a value no less than the channel encoding bitrate plus 4 Mbps.

For example, if the bitrate for the channel is set to 10 Mbps in the encoding settings, the minimum value we recommend for the bandwidth limit bitrate is 14 Mbps.

Important considerations

  • Traffic shaping works for the local switch. Switches connected to the local switch don't respect the policy.
  • If the channel encoding bitrate is set to a value that's less than 4 Mbps and traffic shaping is enabled, the minimum bandwidth limit does not drop below than 4 Mbps.
  • If the channel encoding bitrate value is greater than 95 Mbps and traffic shaping is enabled, the maximum bandwidth limit does not exceed 95 Mbps.
  • If the bandwidth limit is set to auto and the total of the channel bitrate plus 4 Mbps exceeds 95 Mbps, the maximum bandwidth limit does not exceed 95 Mbps.

  • After enabling traffic shaping for a channel using the Admin panel, you can no longer use the Pearl-2 API to clear or configure traffic shaping for that channel. If you currently use the API to configure traffic shaping, see the Technical Notes for your Pearl-2 model for instructions. They're available from the product resources page on the Epiphan.com website.

After traffic shaping is enabled, we recommend that you first test a multicast stream using the auto traffic shaping settings. If your low bandwidth network device is displaying poor video quality, then go ahead and manually set the limit bandwidth bitrate according to the bandwidth of your particular network device.

Set traffic shaping for a multicast stream using the Admin panel

  1. Login to the Admin panel as admin, see Connect to Admin panel.
  1. From the Channels menu, select the channel and click Streaming. The Streaming configuration page opens.
  2. Click New stream and select a multicasting stream as the type: MPEG-TS USP, MPEG-TS RTP/UDP, or RTP/UDP. The new stream is created with the default name Stream 1.
  3. Click the stream name to see the stream settings.

  1. Check Limit bandwidth. The default bitrate is set to auto.
  2. (Optional) Set the Limit bandwidth rate and enter a bitrate value from 4,000 kbps to 95,000 kbps.
  1. Click Apply.