Sending SIP messages

There are two ways to send a SIP message with the SIP for NCC API:

Using SIP for NCC API functions that send SIP messages automatically

The following table lists the SIP for NCC API functions along with the SIP commands and responses they are associated with:

Function

SIP method

Response code

nccAcceptCall

INVITE

180

nccAcknowledgeCall

ACK

request

INVITE

100

nccAnswerCall

INVITE

200

nccAutomaticTransfer

REFER

request

nccDisconnectCall

BYE or CANCEL

request

nccHandleTransferRequest

REFER

202 or 501

nccHoldCall

INVITE

request

nccPlaceCall

INVITE

request

nccRejectCall

INVITE

600, 603, 604, or 606

nccRetrieveCall

INVITE

request

nccSendCapabilityQuery

REQUEST

200

nccSendCapabilityResponse

OPTIONS

200

nccSendPrack

PRACK

request

nccSendPrackResponse

PRACK

200

nccTransferCall

REFER

request

For example, to send a SIP INVITE request when you are placing a call, invoke nccPlaceCall. The nccPlaceCall function generates a SIP INVITE request and sends it automatically.

Note: This method of sending a SIP message is compatible with SIP for NCC 1.0 functionality.

Using nccCallMessage

Use nccSendCallMessage to send SIP messages that cannot be sent using the NCC functions listed in the previous subsection. When you use nccSendCallMessage, include the following information elements with the function:

The following table lists the SIP methods and response codes that you can use with nccSendCallMessage:

SIP method

Response codes

Notes

INVITE used to initiate a dialog

1xx

 

INVITE issued in the context of a dialog (also called a re-INVITE)

request

Used in the connected state only.

1xx – 6xx

Used in the connected state only.

ACK

Used in the connected state only.

The ACK message may be generated automatically, depending on the server configuration.

For example, to send a SIP INVITE request in the context of a dialog (a re-INVITE request), invoke nccSendCallMessage with the following information element values: