SIP Method : MESSAGE
For specific MESSAGE example, refer to SMS over IMS page
According to RFC 3428
Section 4. UAC Processing
- MESSAGE requests do not initiate dialogs. User Agents MUST NOT insert Contact header fields into MESSAGE requests
- If the UAC receives a 200 OK response to a MESSAGE request, it may assume the message has been delivered to the final destination. It MUST NOT assume that the recipient has actually read the instant message. If the UAC receives a 202 Accepted response, the message has been delivered to a gateway, store and forward server, or some other service that may eventually deliver
the message. In this case, the UAC MUST NOT assume the message has been delivered to the final destination. If confirmation of delivery is required for a message that has been responded to with a 202 Accepted, that confirmation must be delivered via some other mechanism
Section 7. UAS Processing
- A UAS receiving a MESSAGE request SHOULD respond with a final
response immediately. Note, however, that the UAS is not obliged to
display the message to the user either before or after responding
with a 200 OK. That is, a 200 OK response does not necessarily mean
the user has read the message.
- A 2xx response to a MESSAGE request MUST NOT contain a body.
- A UAS
MUST NOT insert a Contact header field into a 2xx response.
A UAS which is, in fact, a message relay, storing the message and
forwarding it later on, or forwarding it into a non-SIP domain,
SHOULD return a 202 (Accepted) response indicating that the
message was accepted, but end to end delivery has not been
- A 4xx or 5xx response indicates that the message was not delivered
successfully. A 6xx response means it was delivered successfully,