Sharing Content During Conferences
Polycom®, Inc. 101
Content Sharing Using H.239 Protocol
This protocol is used by H.323 endpoints.
The H.239 protocol allows compliant endpoints to share content stream simultaneously with video.
Cascaded links declare H.239 capabilities, and are supported in Star and MIH cascading topologies. For
more details, see Cascading Conferences - H.239-enabled MIH Topology.
Endpoints may not send content while connecting to an Entry Queue.
Content Sharing Using BFCP Protocol
This protocol is used by SIP endpoints.
The MCU supports BFCP over either TCP or UDP, which enables the MCU to share content with both SIP
client types.

Guidelines for Using SIP BFCP Content

For SIP clients supporting BFCP/TCP or BFCP/UDP:
●BFCP content is not supported over SIP links (in Gateway and cascading scenarios). Therefore, in
cascading environment, the cascaded link must be defined as H.323 for content to be shared.
●BFCP/UDP is supported in both IPv4 and IPv6 addressing modes. BFCP/TCP is supported only in
IPv4 addressing mode.
●Note that Lync endpoints, though considered as SIP endpoints, do not use BFCP to share content,
and use a Microsoft proprietary protocol for that purpose. There are two options to bypass that
limitation:
Polycom CSS plug-in (see Content Sharing via Polycom CSS Plug-in for Microsoft Lync Clients).
This is the preferred option, and is used whenever the CSS plug-in is currently used.
Treating Lync endpoints as Legacy, thus viewing content via the people video layout (see Sending
Content to Legacy Endpoints (CP Only)).
●BFCP utilizes an unsecured channel (port 60002/TCP) even when SIP TLS is enabled. If security is
of higher priority than SIP content sharing, SIP/BFCP can be disabled by manually adding the
ENABLE_SIP_PEOPLE_ PLUS_CONTENT system flag, and setting its value to NO.
●SIP and BFCP capabilities are by default declared to all endpoints.
Capabilities declaration is controlled by the ENABLE_SIP_PPC_FOR_ALL_USER_AGENT system
flag, whose default value is YES, meaning BFCP capability is declared to all vendors’ endpoints.
When set to NO, the MCU declares SIP over BFCP capabilities only to Polycom and Avaya
endpoints. Note that a SIP proxy might remove the agent information, thus preventing the capability
declaration to Polycom and Avaya endpoints as well.
●Set ENABLE_FLOW_CONTROL_REINVITE system flag to NO when SIP BFCP is enabled.
●If the system flags mentioned above do not exist in the system, they must be manually added (see
Modifying System Flags).
Note that since TIP content implies using H.264 content media protocol, endpoint supporting only
H.263 are considered Legacy content endpoints (see Sending Content to Legacy Endpoints (CP
Only)) when TIP content is used.