Info The Transparency Profile is the recommended method of configuring transparency on the SBC Core for new deployments as well as when applying additional transparency configurations to existing deployments. Do not use IPSP flags in these scenarios because the flags will be retired in upcoming releases. Refer to the SBC SIP Transparency Implementation Guide for additional information.
The Transparency Profile is the recommended method of configuring transparency on the SBC Core for new deployments as well as when applying additional transparency configurations to existing deployments. Do not use IPSP flags in these scenarios because the flags will be retired in upcoming releases.
Refer to the SBC SIP Transparency Implementation Guide for additional information.
Microsoft Lync Video Relay
Microsoft (MS) Lync 2013 introduces support for H.264-UC open standard video codec, and enables point-to-point video from Lync endpoints to non-Lync endpoints. With this capability, MS Lync 2013 supports establishing video sessions with other devices that are capable of supporting H.264-UC codec.
MS Lync 2010 supports the older standard codec H.263 which is commonly supported by video devices; however, it is not supported by MS Lync 2013.
The two methods to route video from Lync 2013 are following:
- Static route (via FQDN)
- Non-Lync endpoint registers directly to Lync server
Lync 2010 and Lync 2013 expects STUN/ICE connectivity to be completed before initiating video stream.
The SBC interworks with a Microsoft Lync 2010 or 2013 client by enabling the SIP trunk group
iceLync flag (see SIP Trunk Group - Services - CLI, SIP Trunk Group - Media - CLI for details). When flag is enabled, the SBC relays (passes through) MS Lync video sessions. A Video call originating from Lync typically includes multi-part/alternative content with two SDPs. SBC uses a second SDP to establish the audio/video call.
Lync-capable endpoints such as Polycom RPG clients simulate the Lync endpoint behavior for Presence (it initiates a “SERVICE” method). This and its 200OK response back from Lync needs to be relayed through the SBC. Lync uses BENOTIFY method which is also relayed. Offer/Answer SDP during the STUN connectivity phase includes TCP-ACT attribute for the server reflexive candidates. This is derived from the UDP host candidates. Upon completion of the STUN connectivity checks, the final offer SDP that is sent by the SBC, which includes the “remote-candidate” attribute for remote media IP and the “a=candidate” attribute for local media IP.
Using sRTP for Media
If sRTP is used for media between the SBC and the Lync endpoint (as well as for normal sRTP configuration), configure the SBC to add the lifetime parameter to the crypto attribute for the sRTP-encrypted media streams when it sends SDP toward the endpoint. An example SMM configuration to accomplish this is provided below.
The SBC supports the following call scenarios for MS Lync Video Relay:
- Lync call which starts out as audio and then adds a video stream. In this situation the ICE processing occurs on the newly-added video stream with media being cut-through successfully.
- Lync call which starts out as audio and video and then downgrades to an audio only stream. In this case, the ICE is successfully completed for both audio and video streams. Once the video stream is removed, the audio stream remains unaffected. The SBC ceases all ICE activity on what was previously the video stream.
- The SBC redirects a non-Lync leg of a call toward a Lync endpoint. In this case the ICE processing occurs on the redirected leg and media is cut through appropriately to the Lync endpoint.
- The SBC handles call hold and resume on streams that are established with Lync ICE.
- The SBC interoperates with a Lync 2013 Endpoint offering IPv6 and or IPv4 addresses and Lync 2010 endpoints offering IPv4 addresses for media. The SBC does not support offering both IPv4 and IPv6 addresses at this time.
How to Configure MS Lync Video Relay
The following example procedure configures the SBC for MS Lync-Video relay.
Enable transparency for following headers.
- Configure the following in IP signaling profile:
Enable “DisableHostTranslation”, INFO relay
Enable STUN Support on SIP trunk group facing Lync or Lync-capable endpoints.
Enable Video and RTCP in packet service profile.
rel100Supportflag on the Lync facing the SIP trunk group.
SuppressEmptyFragmentsflag in the TLS profile.
To relay unknown DSP attributes for the trunk group, enable
To configure sRTP for the Packet Service Profile of the trunk group facing Lync.
How to Configure MS Lync/Skype for Remote Desktop Sharing
- Enabling Application Sharing on Ingress and Egress Sip Trunk Group
- Enabling SBC TCP Client Role on Ingress and Egress Sip Trunk Group
- Call Detail Status
Configuring Basic Lync for Media
To configure basic Lync for media, refer to the section How to Configure MS Lync Video Relay.
Once the base configuration is applied to enable support for Lync desktop sharing in the SBC, configure the following parameters and flags:
Setting the non-RTP Media Bandwidth
- The non-RTP media value must be set as non zero.
The value indicates the percentage of RTP bandwidth (which is 95% of overall bandwidth) allocated for application share calls. The value is calculated based on the number of expected application share calls, which is initiated either from Lync clients or from the other third-party applications.
- The bandwidth for Lync initiated application share call is around 500Kbps.
- The bandwidth for remote desktop sessions from UC servers, which are the result of video stream to remote desktop conversion can use more than 1MB data.
Enabling Application Sharing on Ingress and Egress Sip Trunk Group
To configure the parameter
lyncshare on ingress and egress Sip Trunk Group, execute the following commands:
Enabling SBC TCP Client Role on Ingress and Egress Sip Trunk Group
To configure the parameter
iceTcpRole on ingress and egress Sip Trunk Group, execute the following commands:
Call Detail Status
The new stats TCP/LYNC/APPSHARE is added to the media streams of call detail status.