Granted Patent B2

US 8,937,924 · App. 13/246,573 · Granted Jan 20, 2015

Abstract

Claims (32)

1. A method in a core network communicatively connected with a first radio access network (RAN) comprising a first network element, and a second RAN comprising a second network element, comprising:

receiving, by a mobility management node in the core network, a first Non Access Stratum (NAS) message via the second network element from a User Equipment (UE), wherein the UE has, with the first network element, at least one of a Local Internet Protocol (IP) Access (LIPA) packet data network (PDN) connection and a selected IP traffic offload (SIPTO) PDN connection;

detecting, by the mobility management node, that the UE is connected to the second network element that is different from the first network element that has a first identifying characteristic, and wherein the detecting comprises determining that the first NAS message is received with a second identifying characteristic of the second network element different from the first identifying characteristic associated with the at least one of the LIPA PDN connection and the SIPTO PDN connection, the first identifying characteristic stored at the mobility management node; and

in response to the determining that the first NAS message is received with the second identifying characteristic of the second network element different from the first identifying characteristic:

deactivating, by the mobility management node, the at least one of the LIPA PDN connection and the SIPTO PDN connection; and

in response to a condition that no PDN connection remains as a result of the deactivating, sending, by the mobility management node, a second NAS message causing the UE to perform a new attach procedure, wherein the second NAS message includes at least one of an indication to force the UE to perform the new attach procedure, and a cause code with a value that represents at least one of “Implicitly Detached” and “No EPS Bearer Context Activated.”

2. The method of claim 1 , wherein the first NAS message is a Tracking Area Update Request message and the second NAS message is a Tracking Area Update Reject message.

3. The method of claim 1 , wherein said detecting includes determining that the second network element does not support the at least one of the LIPA PDN connection and the SIPTO PDN connection.

4. The method of claim 1 , wherein said detecting is based in part upon bearer context information stored at the mobility management node.

5. The method of claim 4 , further comprising:

maintaining the bearer context information in a memory store, the bearer context information including a gateway IP address.

6. The method of claim 1 , wherein the mobility management node is either a Mobility Management Entity (MME) or a Serving GPRS Support Node (SGSN).

7. The method of claim 1 , wherein the first network element includes a Local Gateway (L-GW) that is associated with the at least one of the LIPA PDN connection and the SIPTO PDN connection.

8. The method of claim 1 , wherein the first network element has connectivity to a Local Gateway (L-GW) that is associated with the at least one of the LIPA PDN connection and the SIPTO PDN connection.

9. The method of claim 1 , wherein the first NAS message is a one of a Tracking Area Update Request message, a Service Request message, an Extended Service Request message, a Routing Area Update message, and a paging response message.

10. The method of claim 1 , wherein the cause code with the value that represents “Implicitly Detached” is to cause the UE to release all bearer contexts.

11. The method of claim 1 , wherein the cause code with the value that represents “No EPS Bearer Context Activated” is to cause the UE to release context information of the UE and establish a new PDN connection.

12. A mobility management node for use in a core network communicatively connected to a first radio access network (RAN) comprising a first network element, and a second RAN comprising a second network element, comprising:

a memory; and

at least one processor coupled to the memory and configured to:

receive a first Non Access Stratum (NAS) message via the second network element from a User Equipment (UE), wherein the UE has, with the first network element, at least one of a Local Internet Protocol (IP) Access (LIPA) packet data network (PDN) connection and a selected IP traffic offload (SIPTO) PDN connection;

detect that the UE is connected to the second network element that is different from the first network element that has a first identifying characteristic, wherein the detecting comprises determining that the first NAS message is received with a second identifying characteristic of the second network element different from the first identifying characteristic associated with the at least one of the LIPA PDN connection and the SIPTO PDN connection, the first identifying characteristic stored at the mobility management node; and

in response to the determining that the first NAS message is received with the second identifying characteristic of the second network element different from the first identifying characteristic:

deactivate the at least one of the LIPA PDN connection and the SIPTO PDN connection; and

in response to a condition that no PDN connection remains as a result of the deactivating, send a second NAS message causing the UE to perform a new attach procedure, wherein the second NAS message includes at least one of an indication to force the UE to perform the new attach procedure, and a cause code with a value that represents at least one of “Implicitly Detached” and “No EPS Bearer Context Activated.”

13. A computer program product comprising a non-transitory computer readable storage medium having computer readable program code embodied therein, said computer readable program code upon execution causing a mobility management node in a core network communicatively connected to a first radio access network (RAN) comprising a first network element and a second RAN comprising a second network element, to:

receive a first Non Access Stratum (NAS) message via the second network element from a User Equipment (UE), wherein the UE has, with the first network element, at least one of a Local Internet Protocol (IP) Access (LIPA) packet data network (PDN) connection and a selected IP traffic offload (SIPTO) PDN connection;

detect that the UE is connected to the second network element that is different from the first network element that has a first identifying characteristic, wherein the detecting comprises determining that the first NAS message is received with a second identifying characteristic of the second network element different from the first identifying characteristic associated with the at least one of the LIPA PDN connection and the SIPTO PDN connection, the first identifying characteristic stored at the mobility management node; and

in response to the determining that the first NAS message is received with the second identifying characteristic of the second network element different from the first identifying characteristic:

deactivate the at least one of the LIPA PDN connection and the SIPTO PDN connection; and

in response to a condition that no PDN connection remains as a result of the deactivating, send a second NAS message causing the UE to perform a new attach procedure, wherein the second NAS message includes at least one of an indication to force the UE to perform the new attach procedure, and a cause code with a value that represents at least one of “Implicitly Detached” and “No EPS Bearer Context Activated.”

14. The computer program product of claim 13 , wherein the detecting includes determining that the second network element does not support the at least one of the LIPA PDN connection and the SIPTO PDN connection.

Assignments (10)