How To Enable RTC Client API Policies

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There are two RTC API policies: PortRange and MaxAudioVideoBitrate. These policies can be set in the registry.

PortRange

PortRange is of type REG_DWORD and specifies the ranges of dynamically allocated ports that the RTC Client API version 1.3 can use to transmit signaling data using SIP and to transmit audio and video data using RTP. If you open specific ranges of ports on a firewall between two clients to allow the clients to communicate, this policy forces the clients to use ports in those ranges. If you do not configure this policy setting, RTC Client API version 1.3 attempts to send and receive SIP and RTP data using ports selected at random throughout the range of 1024 to 65535 inclusive.

You enable this policy by setting the Enabled value to 1.

The following example sets the dynamic port range and media port range:

HKEY_LOCAL_MACHINE
     SOFTWARE
          Policies
               Microsoft
                    Windows
                         RTC
                              Enabled = 00000001
                              MinSipDynamicPort = 00001bbc
                              MaxSipDynamicPort = 00001bbf
                              MinMediaPort = 000014e6
                              MaxMediaPort = 000014e9

Note that if you enable this policy setting, do not create SIP and RTP port ranges that overlap.

When this policy is enabled, both ranges must fall between 1024 and 65535 inclusive. In each range the following conditions must be met:

  • The MinSipDynamicPort must be less than the MaxSipDynamicPort.
  • The SIP range must contain at least two ports
  • The RTP range must contain at least four ports (if the lowest port number in the range is even) or five ports (if the lowest port number in the range is odd)

If you specify a range that violates one of these rules, your application's attempt to create an instance of the RTC Client API version 1.3 will fail.

MaxAudioVideoBitRate

The MaxAudioVideoBitRate value is of type REG_DWORD and limits bandwidth that RTC client applications can use for audio and video calls. If you do not configure this policy setting, RTC client applications use as much bandwidth as is available and necessary for audio and video calls.

The following example sets the bandwidth limit for audio and video calls:

HKEY_LOCAL_MACHINE
     SOFTWARE
          Policies
               Microsoft
                    Windows
                         RTC
                              MaxAudioVideoBitrate = 000320c8