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Cisco TelePresence MCU 4200 Series

Multicast streaming on Cisco acquired Codian/Tandberg products

Multicast streaming on Cisco acquired TANDBERG/Codian Conferencing Products

The Cisco TelePresence MCU and IP VCR support streaming, which involves sending conference media (audio and video) to a remote computer, allowing the user to watch and listen to a conference and also contribute "markup" in the form of text or graphics. The media flows in just one direction, so it is not possible to actually contribute to a conference via streaming.

Multicast streaming can have multiple clients per stream. The stream is made available by network devices (switches and routers) as required. The viewers' experience is not unique because many viewers can subscribe to the same multicast session. The viewer does not have the option to seek though the clip.


Note: You cannot use Windows Media Player to stream in multicast mode on Cisco acquired Codian products.

This article discusses:

Configuring multicast streaming on the Cisco TelePresence MCU

  1. Go to Settings > Streaming.
  2. Complete the General, Codec, and Bit rate choices fields using the online help.
  3. For Multicast transmit IP address range enter the multicast address range required. Valid multicast addresses are between 224.0.0.0 and 239.255.255.255.

    Note: Your chosen range must not conflict with any other multicast address range in use on your network. Further considerations will apply if you wish to multicast over the public Internet. Contact your network administrator for further details about this.
  4. For Media transmit port number range, enter the port range. Valid port numbers are between 1 and 65535. Check with your network administrator before assigning a port range.

    Note: Your chosen IP / port number ranges should be large enough to provide two unique combinations of address and port number for each conference or live recording that you wish to multicast.
  5. Click Apply changes.
  6. For each conference that you wish to multicast, go to the Configuration page for that conference and for Streaming, select Multicast or Unicast and multicast.
  7. When streaming the conference, click Show advanced streaming options. Then select the streaming rate to use and select Prefer multicast.

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Configuring multicast streaming on the IP VCR

  1. Go to Settings > Recording.
  2. In the Recordings settings, for Multicast transmit IP address range enter the multicast address range required. Valid multicast addresses are between 224.0.0.0 and 239.255.255.255.

    Note: Your chosen range must not conflict with any other multicast address range in use on your network. Further considerations will apply if you wish to multicast over the public Internet. Contact your network administrator for further details about this.
  3. For Multicast transmit port number range enter the port range. Valid port numbers are between 1 and 65535. Check with your network administrator before assigning a port range.

    Note: Your chosen IP / port number ranges should be large enough to provide two unique combinations of address and port number for each conference or live recording that you wish to multicast.
  4. Select the Players allowed: either or both of Quicktime and RealPlayer.

  5. Note: Audio cannot be heard when multicast streaming using RealPlayer on the IP VCR.
  6. In the Streaming media settings, complete the fields using the online help. In particular set the two Streaming recording video bit rate options and check the two Multicast check boxes. (These settings will be used for streaming all recordings on this IP VCR.)

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Notes on multicast streaming

Note 1: Multicast streams will be sent through the port configured as the unit's default gateway. This can be changed by going to Network > Routes and adding entries in the Route table for all or part of your Multicast range. Multicast streams must be restarted (by disabling and re-enabling Multicast streaming on the unit in Settings > Streaming or Settings > Recording) in order for changes to the routing table to take effect.

Note 2: Using Multicast without compromising network bandwidth requires a network infrastructure that is multicast aware; that is, supporting IGMP. If your network does not support IGMP, then the multicast streams will be flooded across the subnet and will not be forwarded by your routers.

Note 3: Multicast viewers will notice that they initially see a black screen, building up to the full picture in blocks over a number of seconds. This is because video keyframes are not sent to clients when they start viewing the multicast stream. When using H.263, keyframes will be sent periodically. Unicast viewers do not have this problem because the unit is aware of individual unicast viewers and is able to send keyframes to them as soon as they connect. To force the unit to send a keyframe on a particular stream, you can connect a unicast client to the corresponding conference or live recording. This will cause a keyframe to be sent to all unicast and multicast viewers watching that stream, correcting any video problems the multicast viewers are seeing.

Note 4: Windows Media Player is not supported for multicast streams.

Note 5: There are consequences for streaming if you use the high definition video capture option. See the online help for more information.

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Troubleshooting multicast streaming problems

You may experience a delay in the picture when multicast streaming to a PC. It is perfectly normal for the picture to form over 3 to 5 seconds. This is because keyframes are not sent out on initial connection with multicasting because the unit has no way of knowing when a new viewer has started to watch. Therefore, the picture builds up gradually.

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This article applies to the following products:

  • Cisco TelePresence IP VCR 2200 / MSE VCR blade
  • Cisco TelePresence MCU 4200 / MSE 8420
  • Cisco TelePresence MCU 4500
  • Cisco TelePresence MSE 8510 blade

April 30th, 2011 TAA_KB_108