WO2013037420A1

WO2013037420A1 - Reuse of information element to identify local gateway

Info

Publication number: WO2013037420A1
Application number: PCT/EP2011/066117
Authority: WO
Inventors: Gyorgy Tamas Wolfner
Original assignee: Nokia Siemens Networks Oy
Priority date: 2011-09-16
Filing date: 2011-09-16
Publication date: 2013-03-21

Abstract

Local Internet Protocol (IP) access (LIPA) mobility can be enhanced by permitting standalone Local Gateway (LGW) and handover between femto cells. This ability to find the selected LGW can be achieved by, for example, the reuse of an information element, such as a tunnel endpoint identifier (TEID) or generic routing encapsulation (GRE) key. Thus, for example, a method can include determining a local gateway based on an information element of a session creation response. The method can also include requesting, triggering, or receiving creation of a tunnel to the local gateway determined based on the information element.

Description

DESCRIPTION

TITLE:

Reuse of Information Element to Identify Local Gateway

BACKGROUND:

Field:

Local Internet Protocol (IP) access (LIPA) mobility can be enhanced by permitting standalone Local Gateway (LGW) and handover between femto cells. This ability to find the selected LGW can be achieved by, for example, the reuse of an information element, such as a tunnel endpoint identifier (TEID) or generic routing encapsulation (GRE) key.

Description of the Related Art:

In Release 10 (Rel-10) specifications the 3rd generation partnership project (3GPP) core network sends a correlation identifier to the Home eNodeB (H(e)NB) when a LIPA connection is established. This correlation identifier is used to associate the LIPA connection within the H(e)NB and LGW. The correlation identifier in Rel-10 specifications is either the uplink TEID (when general packet radio service (GPRS) tunneling protocol (GTP) is used over the S5 interface, the interface that can connect a universal mobile telecommunications system (UMTS) long term evolution (LTE) system to the Internet or other packet data networks) or the uplink GRE key (when proxy mobile IP (PMIP) is used over S5) that is used over S5 interface between the serving gateway (SGW) and the local gateway (LGW).

Figure 1 illustrates an LIPA connection establishment in which a correlation identifier is used in Rel-10. As shown in Figure 1 , at S1 , a user equipment (UE) requests the establishment of a packet data network (PDN) connection. At S2, the mobility

management entity (MME) sends a request to create a session to the serving gateway.

Then, at S3, the serving gateway sends a request to create a session to the local gateway, which (in Rel-10) is collocated with the HeNB.

At S4, the local gateway allocates internal resources including an uplink TEID (or GRE key), which is used to uniquely identify the connection within the local gateway. Then, at S5, the local gateway sends back a response to the request to create a session. This response includes the allocated uplink TEID (or GRE key). Next, at S6, the serving gateway sends back to the mobility management entity a response to the request to create a session, including the received uplink TEID (or GRE key).

At S7, the mobility management entity sends to the HeNB a Bearer Setup message or similar message to create a bearer. The message includes the received uplink TEID (or GRE key) as a correlation identifier. At S8, the HeNB/LGW uses the correlation identifier to identify the LIPA connection created within the collocated local gateway (at S4), which corresponds to the requested bearer. This correlation identifier permits the HeNB/LGW to match the bearer request with the LIPA connection. Finally, at S9, the connection establishment continues. SUMMARY:

According to certain embodiments, a method includes determining a local gateway based on an information element of a session creation response. The method also includes requesting, triggering, or receiving creation of a tunnel to the local gateway determined based on the information element.

A method, according to certain embodiments, includes generating an information element, wherein the information element is configured to identify a local gateway. The method also involves including the information element in a session creation response message. An apparatus includes at least one processor and at least one memory including computer instructions, in certain embodiments. The at least one memory and the computer instructions are configured to, with the at least one processor, cause the apparatus at least to determine a local gateway based on an information element of a session creation response. The at least one memory and the computer instructions are also configured to, with the at least one processor, cause the apparatus at least to request, trigger, or receive creation of a tunnel to the local gateway determined based on the information element.

According to certain embodiments, an apparatus includes at least one processor and at least one memory including computer instructions. The at least one memory and the computer instructions are configured to, with the at least one processor, cause the apparatus at least to generate an information element, wherein the information element is configured to identify a local gateway. The at least one memory and the computer instructions are also configured to, with the at least one processor, cause the apparatus at least to include the information element in a session creation response message.

An apparatus, according to certain embodiments, includes determining means for determining a local gateway based on an information element of a session creation response. The apparatus also includes requesting means for requesting, triggering, or receiving creation of a tunnel to the local gateway determined based on the information element.

An apparatus includes, in certain embodiments, generating means for generating an information element, wherein the information element is configured to identify a local gateway. The apparatus also includes incorporating means for including the information element in a session creation response message.

A non-transitory computer-readable medium is, in certain embodiments, encoded with instructions which, when executed in hardware, perform a process. The process includes determining a local gateway based on an information element of a session creation response. The process also includes requesting, triggering, or receiving creation of a tunnel to the local gateway determined based on the information element.

According to certain embodiments, a non-transitory computer-readable medium is encoded with instructions which, when executed in hardware, perform a process. The process includes generating an information element, wherein the information element is configured to identify a local gateway. The process also involves including the information element in a session creation response message.

BRIEF DESCRIPTION OF THE DRAWINGS:

For proper understanding of the invention, reference should be made to the

accompanying drawings, wherein:

Figure 1 illustrates a release 10 local internet protocol access connection establishment in which a correlation identifier is used.

Figure 2 illustrates local internet protocol access connection establishment in which a correlation identifier is used according to certain embodiments.

Figure 3 illustrates a method according to certain embodiments.

Figure 4 illustrates another method according to certain embodiments.

Figure 5 illustrates a system according to certain embodiments of the present invention.

DETAILED DESCRIPTION:

Local IP Access (LIPA) functionality in can be employed in universal mobile telephony system (UMTS) terrestrial radio access network (UTRAN) and evolved UTRAN (E- UTRAN) systems. This feature can permit access of local IP networks from femto cells, which are sometimes referred to as Home NodeBs (HNB) and Home eNodeBs (HeNB). Mobility support may be valuable to such systems.

Conventionally, the H(e)NB and the Local GateWay (LGW), which provides the connectivity to the local IP network, are collocated. Thus, the LIPA connection is released when the user equipment leaves the coverage of the femto cell where the LIPA packet data network (PDN) connection was established. Therefore, conventionally, finding the local gateway from the H(e)NB is not an issue.

However, when LIPA is changed to allow a standalone local gateway, it may be desirable to permit the LIPA connection to be handed over between H(e)NBs, for example, between H(e)NBs connected to the same local network. Therefore some mechanism should be specified how the H(e)NBs find the selected LGW.

Certain embodiments use a part of the TEID or GRE key, which was provided as the correlation identifier, as a local gateway identifier within the local network.

For example, the first octet of the 4-octet TEID can be used to identify the local gateway within the local network. Thus, for example, TEIDs with a value x.y.z belong to LGW1 , 2.x.y.z values belong to LGW2, and so on. In this situation, the H(e)NB can use the 1st octet to identify the LGW (either using configuration data or using a domain name service (DNS) query, for example, <number>.LGW.Iocaldomain). While it may be possible to standardize the part of the TEID that is used for local gateway identification, there is no requirement that such standardization be implemented. Different local networks can use different divisions and types of division of TEID ranges. For example, one network can use 1st octet, but another network can use the 1st 2 octets. It may be sufficient for the purposes of certain embodiments that there is a consistent configuration of the H(e)NBs and local gateways within a given local network.

Figure 2 illustrates a LIPA connection establishment for long term evolution (LTE), which a correlation identifier is employed according to certain embodiments. Although Figure 2 illustrates one embodiment, a similar approach can be used in a universal mobile telephony system (UMTS), although in that case a serving general packet radio system (GPRS) support node (SGSN) would be used instead of mobility management entity, a home NodeB (HNB) would be used instead of home eNodeB (HeNB), and there might be no serving gateway (SGW) in the signaling path.

As shown in Figure 2, connection establishment can have many similarities to the connection establishment shown in Figure 1. For example, at S1 , the user equipment (UE) can send a request to a mobility management entity (MME) for establishment of a packet data network (PDN) connection. Then, at S2, the mobility management entity can send a request to create a session to the serving gateway (SGW).

Once the serving gateway has received a request to create a session, the serving gateway can itself send a request to create a session to a local gateway (LGW) at S3. At S4, the local gateway can allocate internal resources including an uplink TEID (or GRE key), which is used to uniquely identify the connection within the local gateway. According to certain embodiments, unlike in a conventional approach, the local gateway can be configured as to which range of the TEID (or GRE key) values are to be used by the local gateway so as to enable local gateway identification in the HeNB. Each local gateway in the local network should have its own separate TEID (or GRE key) range.

At S5, the local gateway sends back a response to the request to create the session. This response includes the allocated uplink TEID (or GRE key). Then, at S6, the serving gateway sends back to the mobility management entity a session creation response, including the received uplink TEID (or GRE key).

The mobility management entity, at S7, sends a message to the HeNB to set up a bearer. The message includes the received uplink TEID (or GRE key) as a correlation identifier. Then, according to certain embodiments, at S8, the HeNB uses the correlation identifier (uplink TEID or GRE key) to identify the local gateway. Thus, no other information such as an explicit local gateway identifier or local gateway local IP address is needed in the message received at S7. In some embodiments, no explicit local gateway identifier or local gateway local IP address, or the like is provided. Instead, the local gateway is indicated implicitly by the correlation identifier. The HeNB can identify the local gateway either by some configuration data or by, for example, a domain name server (DNS) query using a part of the TEID (or GRE key).

At, S8a, the HeNB sends a request to create a local IP access tunnel to the appropriate local gateway. This request includes the correlation identifier. Then, at S8b, the local gateway can match the local IP access connection created in S4 with the local IP access tunnel establishment request, based on the correlation identifier. Finally, at S9, the connection establishment can continue.

Certain embodiments of the present invention can transfer the local gateway identifier over S5, S1 1 (an interface between the mobility management entity and the serving gateway) and S1-MME (an interface between the mobility management entity and an eNodeB) interfaces. This may permit release 1 1 (Rel-11) LIPA to be deployed with pre- Rel-11 serving gateways. Moreover, it might a mixed deployment scenario easier when both Rel-10 and Rel-11 H(e)NBs are used.

Likewise, certain embodiments do not need to explore the internal IP addressing structure of the local network. For enterprises, this may be a useful feature from the standpoint of security.

Figure 3 illustrates a method according to certain embodiments. The method of Figure 3 can be performed by, for example, a home eNodeB or similar device. As shown in Figure 3, a method can include, at 310, determining a local gateway based on an information element of a session creation response. The determining can be based on a tunnel endpoint identifier or generic routing encapsulation key. In other words, the information element can be or include a tunnel endpoint identifier or generic routing encapsulation key.

The method can also include, at 320, requesting (or triggering or receiving there is no need for an explicit tunnel creation request to be used) creation of a tunnel to the local gateway determined based on the information element. The method can additionally include, at 330, completing a local internet protocol access connection setup after the requesting, triggering, or receiving the creation of the tunnel. The method can also include, at 340, handing over a user equipment from a first home eNodeB to a second home eNodeB.

Figure 4 illustrates another method according to certain embodiments. The method of Figure 4 may be performed by, for example, a local gateway or similar device. The method can include, at 410, generating an information element, wherein the information element is configured to identify a local gateway. The generating the information element can include generating a tunnel endpoint identifier or generic routing encapsulation key. In other words, the information element can be or include a tunnel endpoint identifier or generic routing encapsulation key

The method can also include, at 420, including the information element in a session creation response message. The method can further include, at 430, transmitting the session creation response message. The method can additionally include, at 440, correlating a tunnel request with a local internet protocol access connection based on the information element. The method can also include, at 450, completing a local internet protocol access connection setup after providing the session creation response. The method can further include, at 460, handing over a user equipment from a first home eNodeB to a second home eNodeB. Figure 5 illustrates a system according to certain embodiments. As shown in Figure 5, the system can include a first apparatus 510 (such as a home eNodeB) and second apparatus 520 (such as a local gateway). Each of the apparatuses may be equipped with at least one processor 530, at least one memory 540 (including computer program instructions), and transceiver/network interface card 550. The apparatuses may be configured to communicate with one another over an interface 560, which is shown as a wired interface, but could be a wireless interface.

The at least one processor 530 can be variously embodied by any computational or data processing device, such as a central processing unit (CPU) or application specific integrated circuit (ASIC). The at least one processor 530 can be implemented as one or a plurality of controllers.

The at least one memory 540 can be any suitable storage device, such as a non-transitory computer-readable medium. For example, a hard disk drive (HDD) or random access memory (RAM) can be used in the at least one memory 540. The at least one memory 540 can be on a same chip as the at least one processor 530, or may be separate from the at least one processor 530.

The computer program instructions may be any suitable form of computer program code. For example, the computer program instructions may be a compiled or interpreted computer program.

The at least one memory 540 and computer program instructions can be configured to, with the at least one processor 530, cause a hardware apparatus (for example, a local gateway or a home eNodeB) to perform a process, such as the processes shown in Figures 2-4 or any other process described herein.

Thus, in certain embodiments, a non-transitory computer-readable medium can be encoded with computer instructions that, when executed in hardware perform a process, such as one of the processes described above. Alternatively, certain embodiments of the present invention may be performed entirely in hardware.

One having ordinary skill in the art will readily understand that the invention as discussed above may be practiced with steps in a different order, and/or with hardware elements in configurations which are different than those which are disclosed. Therefore, although the invention has been described based upon these preferred embodiments, it would be apparent to those of skill in the art that certain modifications, variations, and alternative constructions would be apparent, while remaining within the spirit and scope of the invention. In order to determine the metes and bounds of the invention, therefore, reference should be made to the appended claims.

Claims

WHAT IS CLAIM ED IS:

1. A method, comprising:

determining a local gateway based on an information element of a session creation response; and

requesting, triggering, or receiving creation of a tunnel to the local gateway determined based on the information element.

2. The method of claim 1 , wherein the determining is based on a tunnel endpoint identifier or generic routing encapsulation key.

3. The method of claim 1 or claim 2, wherein the determining and requesting, triggering, or receiving is performed by a home eNodeB.

4. The method of any of claims 1 -3, further comprising:

completing a local internet protocol access connection setup after the requesting, triggering, or receiving the creation of the tunnel.

5. The method of any of claims 1 -4, further comprising:

handing over a user equipment from a first home eNodeB to a second home eNodeB.

6. A method, comprising:

generating an information element, wherein the information element is configured to identify a local gateway; and

including the information element in a session creation response message.

7. The method of claim 6, further comprising:

correlating a tunnel request with a local internet protocol access connection based on the information element.

8. The method of claim 6 or claim 7, wherein the generating the information element comprises generating a tunnel endpoint identifier or generic routing encapsulation key.

9. The method of any of claims 6-8, further comprising:

completing a local internet protocol access connection setup after providing the creation response.

10. The method of any of claims 6-9, further comprising:

handing over a user equipment from a first home eNodeB to a second home eNodeB.

11. An apparatus, comprising:

at least one processor; and

at least one memory including computer instructions,

wherein the at least one memory and the computer instructions are configured to, with the at least one processor, cause the apparatus at least to

determine a local gateway based on an information element of a session creation response, and

request, trigger, or receive creation of a tunnel to the local gateway determined based on the information element.

12. The apparatus of claim 11 , wherein the at least one memory and the computer instructions are configured to, with the at least one processor, cause the apparatus at least to determine the local gateway based on a tunnel endpoint identifier or generic routing encapsulation key.

13. The apparatus of claim 11 or claim 12, wherein the apparatus comprises or is comprised in a home eNodeB.

14. The apparatus of any of claims 1 1-13, wherein the at least one memory and the computer instructions are further configured to, with the at least one processor, cause the apparatus at least to complete a local internet protocol access connection setup after the requesting, triggering, or receiving the creation of the tunnel.

15. The apparatus of any of claims 1 1-14, wherein the at least one memory and the computer instructions are further configured to, with the at least one processor, cause the apparatus at least to hand over a user equipment from a first home eNodeB to a second home eNodeB.

16. An apparatus, comprising:

at least one processor; and

at least one memory including computer instructions,

generate an information element, wherein the information element is configured to identify a local gateway, and

include the information element in a session creation response message.

17. The apparatus of claim 16, wherein the at least one memory and the computer instructions are further configured to, with the at least one processor, cause the apparatus at least to correlate a tunnel request with a local internet protocol access connection based on the information element.

18. The apparatus of claim 16 or claim 17, wherein the at least one memory and the computer instructions are configured to, with the at least one processor, cause the apparatus at least to generate the information element by generating a tunnel endpoint identifier or generic routing encapsulation key.

19. The apparatus of any of claims 16-18, wherein the at least one memory and the computer instructions are further configured to, with the at least one processor, cause the apparatus at least to complete a local internet protocol access connection setup after providing the session creation response.

20. The apparatus of any of claims 16-19, wherein the at least one memory and the computer instructions are further configured to, with the at least one processor, cause the apparatus at least to hand over a user equipment from a first home eNodeB to a second home eNodeB.

21. An apparatus, comprising: determining means for determining a local gateway based on an information element of a session creation response; and

requesting means for requesting, triggering, or receiving creation of a tunnel to the local gateway determined based on the information element.

22. The apparatus of claim 21 , wherein the determining is based on a tunnel endpoint identifier or generic routing encapsulation key.

23. The apparatus of claim 21 or claim 22, wherein the apparatus comprises or is comprised in a home eNodeB.

24. The apparatus of any of claims 21-23, further comprising:

setup means for completing a local internet protocol access connection setup after the requesting, triggering, or receiving the creation of the tunnel.

25. The apparatus of any of claims 21-24, further comprising:

transfer means for handing over a user equipment from a first home eNodeB to a second home eNodeB.

26. An apparatus, comprising:

generating means for generating an information element, wherein the information element is configured to identify a local gateway; and

incorporating means for including the information element in a session creation response message.

27. The apparatus of claim 26, further comprising:

correlating means for correlating a tunnel request with a local internet protocol access connection based on the information element.

28. The apparatus of claim 26 or claim 27, wherein the generating the information element comprises generating a tunnel endpoint identifier or generic routing encapsulation key.

29. The apparatus of any of claims 26-28, further comprising:

setup means for completing a local internet protocol access connection setup after providing the session creation response.

30. The apparatus of any of claims 26-29, further comprising:

31. A non-transitory computer-readable medium encoded with instructions which, when executed in hardware, perform a process, wherein the process comprises the method according to any of claims 1-10.