The SendOptionsForInboundCall API procedure can be called by application software to enable or disable the transmission of OPTIONS SIP messages for inbound calls. In some NAT/router/firewall network environments, this may be required in order to allow a network session to be established between the two call endpoints.

For most situations, you do not need to use this API procedure. It is generally used when call endpoints interact with each other directly and not through a proxy server. If you have a proxy server configured that is using Record routing, this API procedure will do nothing.

Network address translation plays an important role in our modern day network environments. However, NAT is also one of the primary reasons why deploying voice over IP solutions is sometimes difficult. If you are deploying your VOIP solution in a network environment that involves NAT, you should make sure you are deploying your VOIP solution using appropriate proxy support and possibly media proxy/boundary controller support.

Namespace:  LanScape
Assembly:  LMEVoipManaged (in LMEVoipManaged.dll) Version: 6.0.5226.26700


public VoipMediaEngine..::.TELEPHONY_RETURN_VALUE SendOptionsForInboundCall(
	bool EnableState
Visual Basic (Declaration)
Public Function SendOptionsForInboundCall ( _
	EnableState As Boolean _
Visual C++
VoipMediaEngine..::.TELEPHONY_RETURN_VALUE SendOptionsForInboundCall(
	bool EnableState
public VoipMediaEngine..::.TELEPHONY_RETURN_VALUE SendOptionsForInboundCall(
	boolean EnableState


Type: System..::.Boolean
Allows application software to enable or disable this feature. Set to a non zero value to enable this feature.

Return Value

If the function succeeds, the return value will be SipSuccess.

If the function fails, the return value will be one of the following values as specified by the VoipMediaEngine..::.TELEPHONY_RETURN_VALUE data type.

Return ValueDescription
This value is returned by telephony API procedures to indicate general API failure. This error value is used as a "catch all error". If you receive this error, check to make sure that all parameters specified in the API procedure call are correct. Particularly, verify that pointers to memory regions are valid. This error return value is only used if a mapping to another specific error value does not exist.

(API return value)

Application software specified an invalid telephony handle in one of the API procedures. This usually indicates memory corruption on the part of application software.

(API return value)



See Also