The present invention relates to a method for routing traffic within a network, wherein the network is comprising a core network and a LIPA/SIPTO (Local IP Access/Selected IP Traffic Offload) enabled network, wherein traffic between a UE (User Equipment) and the LIPA/SIPTO enabled network—a so called LIPA/SIPTO traffic—is broken out at a local breakout point and wherein a mobility support for ongoing broken out LIPA/SIPTO traffic will be provided by an MMF (Mobility Management Function) for realizing a continuation of the LIPA/SIPTO traffic upon a handoff of the UE from one cell to another cell.
Further, the present invention relates to a network, wherein the network is comprising a core network and a LIPA/SIPTO (Local IP Access/Selected IP Traffic Offload) enabled network, wherein traffic between a UE (User Equipment) and the LIPA/SIPTO enabled network—a so called LIPA/SIPTO traffic—is broken out at a local breakout point and wherein a mobility support for ongoing broken out LIPA/SIPTO traffic will be provided by an MMF (Mobility Management Function) for realizing a continuation of the LIPA/SIPTO traffic upon a handoff of the UE from one cell to another cell.
LIPA and SIPTO are important features within modern network technology. In the present document the short form “LIPA/SIPTO” is frequently used. This will mean “LIPA and/or SIPTO”, namely a Local IP Access (LIPA) from a UE into a network and/or the Selected IP Traffic Offload (SIPTO) with regard to a core network. More details with regard to LIPA and SIPTO are obtainable from TS Group Services and System Aspects; Local IP Access and Selected IP Traffic Offload (Rel. 10), 3GPP TR 23.829.
According to already known methods and networks the traffic between a UE and the LIPA/SIPTO enabled network, the LIPA/SIPTO traffic, is broken out at a local breakout point. For realizing such a local breakout point many solutions introduce a novel entity, called “L-GW” (Local Gateway).
Clearly, the two above mentioned options are not achieving the main goals of SIPTO, which is offloading traffic—as locally as possible - from the core network, and result in wasting CN's (Core Network) scarce resources, represented by P/S-GWs.
The problem becomes further significant if we consider, for instance, the example scenario as depicted in
It is an object of the present invention to improve and further develop a method for routing traffic within a network and an according network for allowing an efficient offloading of LIPA/SIPTO traffic from the core network even upon handoff of a UE to a new cell.
In accordance with the invention, the aforementioned object is accomplished by a method comprising the features of claim 1 and by a network comprising the features of claim 23.
According to claim 1 the method is characterized in that the continuation of the LIPA/SIPTO traffic will be performed by a forwarding mechanism providing direct LIPA/SIPTO traffic between local breakout points of different cells.
According to claim 23 the network is characterized by a forwarding mechanism for performing the continuation of the LIPA/SIPTO traffic, wherein the forwarding mechanism is providing direct LIPA/SIPTO traffic between local breakout points of different cells.
According to the invention it has been recognized that it is possible to provide direct LIPA/SIPTO traffic between local breakout points of different cells by a suitable forwarding mechanism. On the basis of such a forwarding mechanism the continuation of the LIPA/SIPTO traffic is possible without an indirect way via the core network. Thus, a very efficient offloading of LIPA/SIPTO traffic from the core network is possible even upon handoff of a UE to a new cell. In other words, LIPA/SIPTO traffic is kept always nearby the UE or an access network of the UE, even after the motion of the UE. The invention ensures that LIPA/SIPTO traffic is offloaded nearby the UE or an access network of the UE and further ensures support of service continuity.
Within a preferred embodiment of the present invention, the forwarding mechanism could be realized by an IP-in-IP tunnelling or by a source routing. However, the invention is not limited to one of the above mentioned mechanisms. Generally, any mechanism that enables forwarding of data between two entities could be used for realizing service continuity.
With regard to a very effective and simple continuation of the LIPA/SIPTO traffic each local breakout point could be realized by an L-GW.
Depending on the individual situation the local breakout point or the L-GW could be realized by an LP-GW (Local PDN (Packet Data Network) Gateway), by an L-GGSN (Local Gateway GPRS (General Packet Radio Service) Support Node) or by a TOF (Traffic Offload Function).
With regard to a very efficient offloading of LIPA/SIPTO traffic each local breakout point or L-GW could be located nearby—in a standalone fashion—and/or could be assigned to or could be collocated with an (H)(e)NB ((Home)(evolved)Node B). This will mean that each local breakout point or L-GW could be located nearby and/or could be assigned to or could be collocated with an HeNB, eNB, HNB or NB depending on the individual network type, LTE (Long Term Evolution), UMTS (Universal Mobile Telecommunications System) or GSM (Global System for Mobile Communications), for example. The invention could be used within all such network types.
Within another preferred embodiment the MMF could be an MME (Mobility Management Entity). However, depending on the individual situation the MMF could be realized separately from a MME at a suitable location within the network.
For providing a reliable service continuity the MMF—by maintaining relevant data—could keep track of UEs with ongoing LIPA/SIPTO traffic or sessions. Alternatively or additionally the MMF—by maintaining relevant data—could keep track of the UE's corresponding original L-GWs, from which the UE has initiated the LIPA/SIPTO traffic or session. Thus, the MMF could provide a suitable management of the continuation of LIPA/SIPTO traffic upon a handoff of the UE from one cell to another cell.
Within a further preferred embodiment at least one L-GW—by maintaining relevant data—could keep track of UEs with ongoing LIPA/SIPTO traffic traversing the L-GW and/or of the L-GWs associated with (H)(e)NBs, to which UEs are currently connecting to, and/or of said (H)(e)NBs, to which UEs are currently connecting to. Alternatively or additionally an L-GW—by maintaining relevant data—could keep track of preferably each LIPA/SIPTO session comprising broken out LIPA/SIPTO traffic, of its corresponding UE and/or of its corresponding original L-GW, from which the corresponding UE has initiated the LIPA/SIPTO session. By each of the above mentioned different functionalities of an L-GW continuation of LIPA/SIPTO traffic could be promoted.
With regard to a very simple method for routing traffic the MMF and/or the L-GW could maintain the relevant data in the form of a table. With regard to a reliable routing of the LIPA/SIPTO traffic the table could be constantly updated, preferably by using a signalling message to/from the MMF.
If the (H)(e)NB is not LIPA/SIPTO enabled or does not have an L-GW assigned to it, a (H)(e)NB could be associated with a P-GW of the core network within the table. Thus, a table could comprise actual and useful routing data, even in the case of a (H)(e)NB which is not LIPA/SIPTO enabled.
Further, with regard to a reliable routing of LIPA/SIPTO traffic, information regarding broken out LIPA/SIPTO traffic or LIPA/SIPTO session or LIPA/SIPTO sessions could be communicated to the L-GW of or associated with a target (H)(e)NB during establishment of the forwarding mechanism providing direct LIPA/SIPTO traffic between the local breakout points.
Within a further preferred embodiment at least one L-GW could inform the MMF about the end of a LIPA/SIPTO traffic or LIPA/SIPTO session or LIPA/SIPTO sessions of a particular UE by a signalling message. On the basis of such an end information the table within the MMF and/or L-GW could be kept actual with regard to no longer existing LIPA/SIPTO traffic or sessions. Within a concrete embodiment of the invention the signalling message could be a LIPA/SIPTO end marker signalling message.
The above signalling message could further be used for providing a charging related info collector unit with LIPA/SIPTO accounting information comprising data required for charging purposes. By such a procedure, a simple charging could be realized.
The data required for charging purposes could comprise a packet count and/or data volume. In any case a reliable charging could be provided.
Within a very simple embodiment of the invention for each UE the LIPA/SIPTO accounting information could be aggregated at the charging related info collector unit. Within a further preferred and very simple embodiment, the charging related info collector unit could be located within the MMF.
For providing a simple and reliable charging LIPA/SIPTO accounting information could be sent preferably directly from an L-GW to a PCEF (Policy Control Enforcement Function) within the core network.
If an UE initially receives LIPA/SIPTO traffic via a not LIPA/SIPTO enabled (H)(e)NB and then later connects to a LIPA/SIPTO enabled (H)(e)NB, a P-GW of the core network could be enabled for offload of LIPA/SIPTO traffic a the P-GW. Thus, the case of a (H)(e)NB which is not LIPA/SIPTO enabled could be comprised by the invention in a very simple way.
The present invention is very useful for all kinds of mobile networks such as GSM, UMTS or LTE, for example.
On the basis of the present invention LIPA/SIPTO traffic can always be kept nearby an access network, wherein such an access network could be realized by (H)(e)NBs.
The invention ensures that LIPA/SIPTO traffic can always be offloaded nearby an access network and efficiently supports service continuity.
Further, the usage of CN's resources is optimized via route optimization of LIPA/SIPTO traffic. Further, on the basis of the present invention distributed charging of LIPA/SIPTO traffic is supported.
There are several ways how to design and further develop the teaching of the present invention in an advantageous way. To this end it is to be referred to the patent claims subordinate to patent claim 1 on the one hand and to the following explanation of preferred examples of the invention, illustrated by the drawing on the other hand. In connection with the explanation of the preferred embodiments of the invention by the aid of the drawing, generally preferred embodiments and further developments of the teaching will we explained. In the drawings
Within the following description of preferred embodiments of the invention the focus is directed on EPS (Evolved Packet System) but the invention can be equally applied to GPRS. In this case, SGSN (Serving GPRS Support Node) would map on to S-GW and MME and GGSN (Gateway GPRS Support Node) would map on to P-GW. Within the scope of the claimed invention L-GW can be LP-GW, L-GGSN or TOF.
An L-GW according to a preferred embodiment of the invention has the following main functionalities or a set of them:
Maintenance of a per UE table as follows:
Within the description of the preferred embodiment the MMF is realized by a MME. Such a MME is comprising the following important features:
Within
It has to be noted that the explained embodiments of the invention refer to SIPTO traffic only. However, the invention and its embodiments are also applicable to LIPA traffic.
Further, when a UE initially receives SIPTO traffic via a non-SIPTO capable (e)NB and then later connects to a SIPTO capable (e)NB, the following enhancements to P-GW are required to enable the offload of SIPTO traffic at P-GW.
The invented solution optimizes LIPA/SIPTO traffic routes and supports service continuity. An advantage of invention compared to current state of the art is the efficient traffic offloading along with efficient mobility support.
Many modifications and other embodiments of the invention set forth herein will come to mind the one skilled in the art to which the invention pertains having the benefit of the teachings presented in the foregoing description and the associated drawings. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
Number | Date | Country | Kind |
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10001210.3 | Feb 2010 | EP | regional |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2011/000548 | 2/7/2011 | WO | 00 | 8/3/2012 |