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The Sonus SBC Portfolio supports relaying up to six media streams.

  • One media stream is reserved for audio. An audio stream is required for video calls.
  • The remaining five streams are shared between video, BFCP-UDP, BFCP-TCP (RFC 4583), and Far End Camera Control (RFC 4753).

A video stream is established at call setup time in conjunction with an audio stream, or added to an existing audio call. The audio and video streams of a video call may have the same or different remote IP addresses, but different UDP or transport port numbers. A video stream is either bidirectional or unidirectional, and its direction is changeable after a call is established.

The SBC also offers control over the TCP port range to be used for the relayed BFCP-TCP streams.

By default, the SBC relays all video codecs (static or dynamic payloads). For example, H.261, H.263-2000, H.263-1998, H.264-SVC, and VP8 are relayed by default. Policy controls are available to manipulate the codec list. For the list of supported codecs, see Supported Codecs and Transcoding. To configure the relaying of video codecs, see Codec Entry (EMA) or Codec Entry (CLI).

Network Address and Port Translation (NAPT) processing is supported on the video RTP stream of a video call. The SBC supports direct media between end points behind the same NAPT module provided the SIP trunk groups for all such endpoints have the same directMediaGroupId. For more information about Direct Media, see Direct Media.

The SBC also supports SRTP for video streams. See SRTP for Media for details.

Policy controls are available to manipulate the Video Codec list, SDP video "media line" related bandwidth attributes, and also to facilitate packet marking for QoS of video streams. See Common IP Attributes (SIP)  to send RTCP port in outgoing SDP. To facilitate video peering and conferencing flows, the SBC has the ability to relay a set of SDP attributes at the audio "media level" (see sipTrunkGroup media (CLI)) and session level (see sipTrunkGroup signaling (CLI)).

For performance details, see SBC 7000 Performance Metrics.

SIP-SIP Video

The SBC manages peering video flows and conferencing in the following manner.

The SBC relays most attributes and lines in the SDP corresponding to Video, BFCP and FECC streams. Only a small set of attributes/lines are manipulated to relay media through the SDP, for example:

  • C line
  • a=sendonly/recvonly/inactive/sendrecv
  • a=crypto
  • b=TIAS/AS

If relaying certain attributes/lines is undesirable, use SIP Message Manipulation (SMM) to delete those particular attributes.

To facilitate video peering and conferencing flows, the SBC relays SDP attributes at the audio "media level" and at the session level. This ability is controlled using the SIP Trunk Group media flag "sdpAttributesSelectRelay". For example:

% set addressContext default zone INTERNAL sipTrunkGroup SIP_INT media sdpAttributesSelectiveRelay <disabled | enable>

This flag controls the selective relay of unknown SDP attributes at the session level, and selective relay of unknown SDP attributes in core audio stream.

The example scenarios below depict the effects of enabling/disabling this flag to session, core and video streams:

 

Scenario

 

SDP Stream Offers

Flag OnFlag Off
SessionCoreVideoSessionCoreVideo
1Audio only(tick) relayed(tick) relayed--(error) dropped(error) dropped--
2Audio only, and then...(tick) relayed(tick) relayed--(error) dropped(error) dropped--
Audio + Video(tick) relayed(tick) relayed(tick)(error) dropped(error) dropped(tick)
3Audio + Video(tick) relayed(tick) relayed(tick)(error) dropped(error) dropped(tick)
Audio + Video(tick) relayed(tick) relayed(tick)(error) dropped(error) dropped(tick)

The SBC also offers control over the TCP port range for the relayed BFCP-TCP streams.

The Video and other conference-related streams are allowed to pass through when the Packet Service Profiles on both call legs allow video (non-zero maxVideoBandwith value as shown in example below).

% set profiles media packetServiceProfile INGRESS videoCalls maxVideoBandwith 2000
% set profiles media packetServiceProfile EGRESS videoCalls maxVideoBandwith 2000

The “Floor Control” feature is the process by which access to a shared resource, or shared whiteboard, is controlled by granting access to participants in a multiparty communication session using the Binary Floor Control Protocol (BFCP) whereby a separate TCP connection is used for each BFCP session.

For help with configuring SIP video, see Configuring SIP-SIP Video page.

H.323-H.323 Video

The SBC supports H.323-H.323 video peering scenarios, for example H.323-H.323 call with an audio and video stream. Unlike SIP video where all codecs are relayed through the SBC, H.323 only supports a subset of SIP video codecs (see Supported Codecs and Transcoding).

A video stream is allowed to pass through if the Packet Service Profiles on both call legs allow video (non-zero maxVideoBandwith value as shown in above example.

For help with configuring H.323 video, see Configuring H.323-H.323 Video page.

References

To:See page:
Enable RTCP relay

EMA: Packet Service Profile

CLI: Packet Service Profile (CLI)

Relay SDP at media level

EMA: SIP Trunk Group - Media

CLI: sipTrunkGroup media (CLI)

Relay SDP at session level

EMA: SIP Trunk Group - Signaling

CLI: sipTrunkGroup signaling (CLI)

Relay video codecs

EMA: Codec Entry

CLI: Codec Entry (CLI)

Configure codec list profile

EMA: Codec List Profile

CLI: Codec List Profile (CLI)

Send RTCP port in outgoing SDP

EMA: IP Signaling Profile (EMA)

CLI: IP Signaling Profile (CLI)