Methods of handling an overload situation of a session initiation protocol, SIP node in a telecommunication network, as well as related SIP nodes

1. A method of handling an overload situation of a Session Initiation Protocol, SIP, node in a telecommunication network, the method comprising:

receiving, by a proxy SIP node in the telecommunication network, an SIP request for requesting a service in the telecommunication network;

forwarding, by the proxy SIP node, the SIP request to a service SIP node in the telecommunication network;

receiving, by the proxy SIP node, from the service SIP node, a Server Failure Response message, the Server Failure Response message comprising an indication that the service SIP node cannot fulfil the SIP request due to an overload situation at the service SIP node and a SIP Reason Header field including automatic congestion level information; and

restricting, by the proxy SIP node, future SIP traffic to the service SIP node based on the received Server Failure Response message, restricting the future SIP traffic including preventing at least one message from being transmitted, by the proxy SIP node, to the service SIP node.

2. The method in accordance with claim 1 , wherein the method further comprises:

transmitting, by the proxy SIP node, triggered by the received Server Failure Response message, to a SIP node from which the proxy SIP node initially received the SIP request, a further Server Failure Response message, wherein the further Server Failure Response message does not comprise the indication that the service SIP node cannot fulfil the SIP request due to an overload situation at the service SIP node.

3. The method in accordance with claim 1 , wherein the received Server Failure Response message, by the proxy SIP node, comprises an indication of a level of the overload situation at the service SIP node, and wherein the restricting comprises:

restricting, by the proxy SIP node, an amount of the future SIP traffic to the service SIP node based on the indication of the level of the overload situation.

4. The method in accordance with claim 1 , wherein the received Server Failure Response message is a 503 Service Unavailable message.

5. The method in accordance with claim 1 , wherein the SIP request is a SIP invite message for requesting a call to be established between two User Equipment, UE, in the telecommunication network.

6. The method in accordance with claim 2 , wherein the received Server Failure Response message, by the proxy SIP node, comprises an indication of a level of the overload situation at the service SIP node, and wherein the restricting comprises:

restricting, by the proxy SIP node, an amount of the future SIP traffic to the service SIP node based on the indication of the level of the overload situation.

7. The method in accordance with claim 2 , wherein the received Server Failure Response message is a 503 Service Unavailable message.

8. A method of handling an overload situation of a Session Initiation Protocol, SIP, node in a telecommunication network, wherein the method comprises:

receiving, by a service SIP node in the telecommunication network, from a proxy SIP node in the telecommunication network, an SIP request for requesting a service in the telecommunication network;

detecting, by the service SIP node, an overload situation at the service SIP node; and

transmitting, by the service SIP node, to the proxy SIP node, a Server Failure Response message, the Server Failure Response message comprising an indication that the service SIP node cannot fulfil the SIP request due to an overload situation at the service SIP node and a SIP Reason Header field including automatic congestion level information, the Server Failure Response message triggering the proxy SIP node to restrict future SIP traffic to the service SIP node including preventing at least one message from being transmitted, by the proxy SIP node, to the service SIP node.

9. The method in accordance with claim 8 , wherein the transmitted received Server Failure Response message, by the service SIP node, comprises an indication of a level of the overload situation at the service SIP node.

10. The method in accordance with claim 8 , wherein the transmitted Server Failure Response message is a 503 Service Unavailable message.

11. The method in accordance with claim 8 , wherein the SIP request is a SIP invite message for requesting a call to be established between two User Equipment, UE, in the telecommunication network.

12. A proxy Session Initiation Protocol, SIP, node for supporting the handling of an overload situation of a SIP node in a telecommunication network, the proxy SIP node comprising:

receive equipment configured to receive an SIP request for requesting a service in telecommunication network;

transmit equipment configured to forward the SIP request to a service SIP node in the telecommunication network;

the receive equipment being further configured to receive, from the service SIP node, a Server Failure Response message, the Server Failure Response message comprising an indication that the service SIP node cannot fulfil the SIP request due to an overload situation at the service SIP node and a SIP Reason Header field including automatic congestion level information; and

the proxy SIP node further comprises process equipment configured to restrict future SIP traffic to the service SIP node based on the received Server Failure Response message, restricting the future SIP traffic including preventing at least one message from being transmitted, by the proxy SIP node, to the service SIP node.

13. The proxy SIP node in accordance with claim 12 , wherein the transmit equipment is further configured to transmit, triggered by the received Server Failure Response message, to a SIP node from which the proxy SIP node initially received the SIP request, a further Server Failure Response message, wherein the further Server Failure Response message does not comprise the indication that the service SIP node cannot fulfil the SIP request due to an overload situation at the service SIP node.

14. The proxy SIP node in accordance with claim 12 , wherein the received Server Failure Response message, by the proxy SIP node, comprises an indication of a level of the overload situation at the service SIP node, and wherein the process equipment is further configured to restrict an amount of the future SIP traffic to the service SIP node based on the indication of the level of the overload situation.

15. The proxy SIP node in accordance with claim 12 , wherein the received Server Failure Response message is a 503 Service Unavailable message.

16. The proxy SIP node in accordance with claim 12 , wherein the SIP request is a SIP invite message for requesting a call to be established between two User Equipment, UE, in the telecommunication network.

17. A service Session Initiation Protocol, SIP, node for supporting the handling of an overload situation of a Session Initiation Protocol, SIP, node in a telecommunication network, the service SIP node comprising:

receive equipment configured to receive, from a proxy SIP node in the telecommunication network, an SIP request for requesting a service in the telecommunication network;

detect equipment configured to detect an overload situation at service SIP node;

transmit equipment configured to transmit to the proxy SIP node, a Server Failure Response message, the Server Failure Response message comprising an indication that the service SIP node cannot fulfil the SIP request due to an overload situation at the service SIP node and a SIP Reason Header field including automatic congestion level information, the Server Failure Response message triggering the proxy SIP node to restrict future SIP traffic to the service SIP node including preventing at least one message from being transmitted, by the proxy SIP node, to the service SIP node.

18. The service SIP node in accordance with claim 17 , wherein the transmitted received Server Failure Response message comprises an indication of a level of the overload situation at the service SIP node.

19. The service SIP node in accordance with claim 17 , wherein the transmitted Server Failure Response message is a 503 Service Unavailable message.

20. The service SIP node in accordance with claim 17 , wherein the SIP request is a SIP invite message for requesting a call to be established between two User Equipment, UE, in the telecommunication network.