WO2013050070A1

WO2013050070A1 - Mechanism for triggering offloading procedure in case of traffic congestion

Info

Publication number: WO2013050070A1
Application number: PCT/EP2011/067382
Authority: WO
Inventors: Jouni Korhonen; Teemu Savolainen
Original assignee: Nokia Siemens Networks Oy; Nokia Corporation
Priority date: 2011-10-05
Filing date: 2011-10-05
Publication date: 2013-04-11

Abstract

There is provided a mechanism for triggering offloading in the case that a traffic congestion occurs in a network part. When a traffic congestion state in a communication network part is detected, a congestion indication comprising an information element indicating a request for initializing a traffic offloading procedure to another communication path is sent to a communication network control element. The communication network control element determines, on the basis of a traffic congestion state, whether a traffic offloading in a communication network part is to be initialized, and sends, in case the determination of the offloading determining portion is affirmative, an offloading indication to a host network element in the communication network part, wherein the offloading indication triggers offloading of traffic to another communication path.

Description

DESCRIPTION

Title

Mechanism for triggering offloading procedure in case of traffic congestion

BACKGROUND OF THE INVENTION

Field of the invention

The present invention relates to a mechanism for triggering offloading in the case that a traffic congestion occurs in a network part. In particular, the present invention is related to apparatuses, methods and computer program products providing a mechanism by means of which an offloading procedure allowing offloading of communication traffic from one communication path to another communication path can be triggered in a dynamic manner in case traffic congestion or the like is detected to happen in some part of a communication network.

Related background Art

Prior art which is related to this technical field can e.g. be found by the technical specification 3GPP TS 23.060, Technical Specification Group Services and System Aspects, General Packet Radio Service (GPRS); Service description, for example according to version 10.4.0, 3GPP TS 23.401 Technical Specification Group Services and System Aspects, General Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access, for example according to version 10.4.0, and 3GPP TS 29.274 Technical Specification Group Core Network and Terminals, 3GPP Evolved Packet System (EPS); Evolved General Packet Radio Service (GPRS) Tunnelling Protocol for Control plane (GTPv2-C); Stage 3, for example according to version 10.3.1.

The following meanings for the abbreviations used in this specification apply:

ANDSF access network discovery and selection function

BS base station

BSC base station controller

eNB evolved NodeB

EPS evolved packet system

GGSN gateway GPRS support node

GPRS General Packet Radio Service

GTP GPRS tunneling protocol GTP-C GTP Control Plane

GTP-U GTP User Plane

IP Internet protocol

IPv6 Internet Protocol version 6

lu-PS Interface between Radio Network System and core network

LMA local mobility anchor

LTE Long Term Evolution

LTE-A LTE Advanced

MAG mobile access gateway

MME mobility management entity

PDN Packet Data Network

P-GW Packet Data Gateway

PMIPv6 Proxy Mobile IPv6

RA routing advertisement

RAT radio access technology

RNC radio network controller

S-GW serving gateway

SGSN serving GPRS support node

UE user equipment

In the last years, an increasing extension of communication networks, e.g. of wire based communication networks, such as the Integrated Services Digital Network (ISDN), DSL, or wireless communication networks, such as the cdma2000 (code division multiple access) system, cellular 3rd generation (3G) and fourth generation (4G) communication networks like the Universal Mobile Telecommunications System (UMTS), enhanced communication networks based e.g. on LTE or LTE-A, cellular 2nd generation (2G) communication networks like the Global System for Mobile communications (GSM), the General Packet Radio System (GPRS), the Enhanced Data Rates for Global Evolutions (EDGE), or other wireless communication system, such as the Wireless Local Area Network (WLAN), Bluetooth or Worldwide Interoperability for Microwave Access (WMAX), took place all over the world. Various organizations, such as the 3rd Generation Partnership Project (3GPP), Telecoms & Internet converged Services & Protocols for Advanced Networks (TISPAN), the International Telecommunication Union (ITU), 3rd Generation Partnership Project 2 (3GPP2), Internet Engineering Task Force (IETF), the IEEE (Institute of Electrical and Electronics Engineers), the WiMAX Forum and the like are working on standards for telecommunication network and access environments. Examples for new communication technologies are for example LTE and LTE-A of 3GPP.

One fundamental problem in communication networks is that all network resources are limited, including processing time and capacity of network elements and link throughput capacities. Thus, due to changing load and number of users, congestion at a network part, for example at an access network level or in a core network level, or the like, may happen. Congestion occurs, for example, when a link or node is carrying so much data that its quality of service deteriorates by such an amount that a proper communication is not possible anymore. Typical effects include queuing delay, packet loss or the blocking of (new) connections.

There are several approaches for controlling traffic flow in communication networks. For example, access network discovery and selection function (ANDSF) provides tools to tell a UE when it is e.g. in a WiFi coverage area, i.e. to set a priority for an access network.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a mechanism by means of which an offloading procedure allowing offloading of communication traffic from one communication path to another communication path can be triggered in a dynamic manner in case traffic congestion or the like is detected to happen in some part of a communication network.

This object is achieved by the measures defined in the attached claims.

According to an example of an embodiment of the proposed solution, there is provided, for example, an apparatus comprising a detecting processing portion configured to detect a traffic congestion state in a communication network part, and a transmitting processing portion configured to send to a communication network control element a congestion indication comprising an information element indicating a request for initializing a traffic offloading procedure to another communication path.

Furthermore, according to an example of an embodiment of the proposed solution, there is provided, for example, a method comprising detecting a traffic congestion state in a communication network part, and sending to a communication network control element a congestion indication comprising an information element indicating a request for initializing a traffic offloading procedure to another communication path.

According to further refinements, there may be comprised one or more of the following features:

- a level of congestion in the communication network part may be determined, and on the basis of the determined level of congestion it may be decided whether traffic offloading at the communication network part is to be requested, the congestion indication may be transmitted in case it is decided that traffic offloading is to be requested;

- it may be detected that the traffic congestion state is released, wherein a congestion release indication may be sent to the communication network control element comprising an information element indicating that the traffic offloading procedure to another communication path can be stopped;

- a traffic congestion at a communication network path being located in a downlink direction may be detected;

- with the congestion indication, at least one of access technology information indicating an access technology at the communication network part where the traffic congestion occurs, congestion level information indicating a level of the traffic congestion, recipient information indicating which terminal nodes are to be involved in the traffic offloading procedure, and one of a traffic offloading request and a traffic offloading stop request may be sent;

- the apparatus or the method may be part of at least one of an access network element, an access network control element, a core network control element, and a gateway network element.

Moreover, according to an example of an embodiment of the proposed solution, there is provided, for example, an apparatus comprising an offloading determining portion configured to determine, on the basis of a traffic congestion state, whether a traffic offloading in at least one communication network part is to be initialized, and an offloading requesting portion configured to send, in case the determination of the offloading determining portion is affirmative, an offloading indication to a host network element in the at least one communication network part, wherein the offloading indication is adapted to trigger offloading of traffic to another communication path.

In addition, according to an example of an embodiment of the proposed solution, there is provided, for example, a method comprising determining, on the basis of a traffic congestion state, whether a traffic offloading in at least one communication network part is to be initialized, and sending, in case the determination of the traffic offloading is affirmative, an offloading indication to a host network element in the at least one communication network part, wherein the offloading indication is adapted to trigger offloading of traffic to another communication path.

- a traffic congestion state in a communication network part may be detected, and a congestion indication comprising an information element indicating a request for initializing a traffic offloading procedure to another communication path may be received, wherein it may be determined that the traffic offloading is to be initialized when a traffic congestion state in the communication network part is detected, or a congestion indication is received;

- in case it is determined that traffic offloading in the communication network part can be stopped, an indication may be sent to the host network element to use a normal communication path being set by default in the at least one communication network part; - one or more host network elements being located in the at least one communication network part may be selected as recipient for the offloading indication; - at least one of access technology information indicating an access technology at the communication network part where the traffic congestion occurs, congestion level information indicating a level of the traffic congestion, recipient information indicating to which host network elements the offloading indication is to be sent, and one of a traffic offloading request and a traffic offloading stop request may be received and processed, wherein it may be determined on the basis of the received information whether or not the offloading indication is sent to the host network element, and parameters of an offloading procedure triggered by the offloading indication may be set;

- the offloading indication may be sent to the host network element by using an Internet Protocol layer signaling;

- the offloading indication may comprise an information element indicating a preference for a type of another communication path to which traffic is to be offloaded;

- an activity state of the host network element to which the offloading indication is to be sent may be determined, wherein the transmission of the offloading indication to a host network element whose activity state is determined to be inactive or idle may be postponed;

- the apparatus or the method may be comprised in a core network control element, in particular a gateway network element.

In addition, according to examples of the proposed solution, there is provided, for example, a computer program product for a computer, comprising software code portions for performing the steps of the above defined methods, when said product is run on the computer. The computer program product may comprise a computer-readable medium on which said software code portions are stored. Furthermore, the computer program product may be directly loadable into the internal memory of the computer and/or transmittable via a network by means of at least one of upload, download and push procedures.

By virtue of the proposed solutions, it is possible to provide a mechanism by means of which it is possible for an operator to attract traffic to cellular network more easily, and hence possibly provide better user experience and improved transport capabilities for user data. That is, instead of a static offloading scheme without consideration of congestion or the like, it is possible to provide an offloading procedure which can be triggered in a dynamic manner in case traffic congestion in some part of a communication network is detected. Specifically, it is possible to indicate preference for hosts to perform offloading of communications while taking into account variance in network congestion state.

Furthermore, it is possible to consider also parameters in the decision like unknown traffic condition in the network to which traffic shall be offloaded, i.e. to provide a deciding instance such as a control network node or the like which decides on sending or not sending an indication to a host like a user equipment to offload communications from a network known to provide e.g. good connectivity to another network with unknown qualities. In other word, a mechanism is provided which sends offloading triggers dynamically when a network is congested at some level, so that the risk of offloading a user equipment from network with proper capacity to another network with possibly less capacity is decreased. Furthermore, the present invention provides the possibility to guide a host like a user equipment to offload traffic with a single signaling mechanism, such as an I P layer based signaling, independent of the location of congestion. That is, even if the network part where the congestion occurs does not have a direct connection allowing to indicate offloading requirement to the host, e.g. is not able to send an IP packet or the like to the UE, a corresponding control network element can be triggered to send the indication in the desired way, allowing the provision of a single signaling mechanism. Thus, the present invention allows for example that in case of a congestion in a cellular network, offloading procedures can be started, wherein proper signaling methods like one using GTP and Internet Protocol route configuration methods using Internet Control Message Protocol version 6 (ICMPv6) are applicable. However, the principles of the present invention are applicable also to other network technologies.

In addition, examples of embodiments of the present invention are easy to be

implemented. As a user equipment may operate in accordance with common procedures, i.e. may use default route preferences, congestion-related offloading indications according to examples of embodiments of the invention do not require specific support from a handset device or the like that already supports common offloading procedures.

The above and still further objects, features and advantages of the invention will become more apparent upon referring to the description and the accompanying drawings.

BRIEF DESCRI PTION OF THE DRAWINGS

Fig. 1 shows a diagram illustrating a communication network structure where examples of embodiments of the invention are applicable.

Fig. 2 shows a signaling diagram illustrating a procedure for congestion signaling and offloading signaling according to examples of embodiments of the invention in a network like that shown in Fig. 1 .

Fig. 3 shows a flowchart illustrating a processing executed in a communication network element according to examples of embodiments of the invention.

Fig. 4 shows a flowchart illustrating a processing executed in a communication network control element according to examples of embodiments of the invention.

Fig. 5 shows a block circuit diagram of a communication network element including processing portions conducting functions according to examples of embodiments of the invention.

Fig. 6 shows a block circuit diagram of a communication network control element including processing portions conducting functions according to examples of embodiments of the invention.

Fig. 7 shows a diagram illustrating an implementation example of an embodiment of the invention.

Fig. 8 shows a diagram illustrating another implementation example of an embodiment of the invention. Fig. 9 shows a diagram illustrating a further implementation example of an embodiment of the invention.

Fig. 10 shows a diagram illustrating a still further implementation example of an embodiment of the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

In the following, examples and embodiments of the present invention are described with reference to the drawings. For illustrating the present invention, the examples and embodiments will be described in connection with a cellular communication network based on a 3GPP communication system or LTE based communication system as a first example of a communication network (i.e. a network where congestion is detected and from which traffic is to be offloaded), and a data communication network like a WiFi based network as a second example of a communication network (i.e. a network to which traffic is to be offloaded). However, it is to be noted that the present invention is not limited to an application using such types of communication systems, but is also applicable in other types of communication systems and the like. For example the first example of a communication network (i.e. a network where congestion is detected and from which traffic is to be offloaded) may be a WiFi-based network, and the second example of a communication network (i.e. a network to which traffic is to be offloaded) may be a cellular 3GPP based network. Also other types of network may be used as one or both of the first and second example of communication network.

A basic system architecture of a communication network may comprise a commonly known architecture of a communication system comprising a wired or wireless access network subsystem and a core network. Such an architecture may comprise one or more access network control elements, radio access network elements, access service network gateways or base transceiver stations, such as a base station (BS) or eNB, with which a communication network element or device like a host, such as a UE or another device having a similar function, such as a modem chipset, a chip, a module etc., which can also be part of a UE or attached as a separate element to a UE, or the like, is capable to communicate via one or more channels for transmitting several types of data.

Furthermore, core network elements such as gateway network elements, serving nodes, policy and charging control network elements, mobility management entities and the like are usually comprised.

The general functions and interconnections of the described elements, depending on the actual network type, are known to those skilled in the art and described in corresponding specifications so that a detailed description thereof is omitted herein. However, it is to be noted that several additional network elements and signaling links may be employed for a communication connection to or from UEs or network nodes (access network nodes, core network nodes etc.), besides those described in detail herein below.

Furthermore, the described network elements, such as communication network elements like UEs, communication network elements like BSs or eNBs, core network elements like gateway nodes (GGSN etc.) and the like, as well as corresponding functions as described herein may be implemented by software, e.g. by a computer program product for a computer, and/or by hardware. In any case, for executing their respective functions, correspondingly used devices, nodes or network elements may comprise several means and components (not shown) which are required for control, processing and

communication/signaling functionality. Such means may comprise, for example, one or more processor units including one or more processing portions for executing instructions, programs and for processing data, memory means for storing instructions, programs and data, for serving as a work area of the processor or processing portion and the like (e.g. ROM, RAM, EEPROM, and the like), input means for inputting data and instructions by software (e.g. floppy diskette, CD-ROM, EEPROM, and the like), user interface means for providing monitor and manipulation possibilities to a user (e.g. a screen, a keyboard and the like), interface means for establishing links and/or connections under the control of the processor unit or portion (e.g. wired and wireless interface means, an antenna, etc.) and the like. It is to be noted that in the present specification processing portions should not be only considered to represent physical portions of one or more processors, but may also be considered as a logical division of the referred processing tasks performed by one or more processors.

Fig. 1 shows a diagram illustrating a communication network structure where examples of embodiments of the invention are applicable. Specifically, Fig. 1 is related to an example of a cellular communication network, where reference sign 10 denotes a host network element like a UE communicating with the network, i.e. which produces traffic to be transported via the network. Reference sign 20 denotes a communication network control element like a gateway node, for example a GGSN or a PGW, which has a signaling connection to the host network elements for informing them about preferences for networks to be used for communication, for example. Reference sign 30 denotes a network element of a core network, such as a SGW or SGSN. Reference signs 40 and 41 denote network elements being used as access network control elements, such as BSC, RNC or MME. Reference sign 50 denotes an network element used as an access network element, such as a NS or eNB, wherein reference sign 51 denotes a cell covered by one (or more) of the access network elements 50. It is to be noted that the access network element may be covering different kinds of cells, such as macro cells, pico cells and the like.

Furthermore, Fig. 1 illustrates a possible movement of the UE 10 between cells wherein a connection to the network remains established. In an initial state, when no cell congestion or the like is detected or taken into account when choosing access network type to use, the UE 10 keeps connected to the initial network.

Fig. 2 shows a signaling diagram illustrating a procedure for congestion detection and signaling as well as offloading signaling according to examples of embodiments of the invention. Specifically, the functions of the mechanism according to examples of embodiments of the invention will be explained in connection with a network structure like that shown in Fig. 1.

Basically, network congestion may happen at various places or network parts of the communication network. For example, in the network structure shown in Fig. 1 , i.e. in a 3GPP-based cellular network, congestion may occur at least at the following network parts or levels:

1. PDN GW/GGSN 20 2. SGW/SGSN 30

3. RNC/BSC/MME 40, 41

4. BTS/(e)Node B 50

When congestion is detected, it is a goal to guide the host network element or UE 10 being located in a network part being affected by the congestion to offload traffic.

Preferably, the offloading indication is sent to the host network element by a single signaling mechanism, such as a single IP-layer mechanism, independent of the location of congestion.

Since not each level of the network may have the possibility to signal an offloading indication to the host by means of the selected signaling mechanism, according to examples of embodiments of the invention, the offloading indication is provided to the host network element in a centralized manner. That is, since e.g. only a specific communication network control element, such as PDN GW/GGSN 20, is able to generate an IP packet required to signal to the host network element 10 the proposal to offload (e.g. in form of a preference indication for a network type to be used for (further) communication), other network elements which are not able to generate corresponding signals inform the communication network control element about the requirement for offloading, i.e. to inform about a congestion on their level or network part.

In other word, in case a congestion is detected on a level of the communication network control element, i.e. the gateway node like GGSN 20, the gateway is able to send an offloading indication (e.g. in IPv6 Router Advertisement or the like) to host network elements like UE 10. In case the congestion occurs on a level being located in the downlink direction, and is detected by a network node on this level, i.e. when the congestion happens between a host and the gateway node, according to examples of the invention, the gateway node is informed about the congestion by a corresponding signaling. In this signaling, the respective network element (e.g. SGSN 30, BSC 40 or the like) located between the host and the gateway requests the gateway to indicate offloading need to the host. As an example for the singling mechanism for the offloading indication, a signal used e.g. for indicating preferences of routings to the network may be used, for example Router Advertisement message with default router preferences and an indication that it is needed to offload (or not offload) traffic to another network than the network selected for traffic by default or the like.

Fig. 2 shows a message sequence chart where an access network element, such as a base station (BS 50) detects a congestion state on the corresponding network part (or level).

First, in step S5, it is assumed that the UE 10 has a preference to use the cellular network for sending data, for example due to default settings or due to corresponding signaling from the network. Then, in step S10, the BS 50 detects a congestion on the cell level and sends in step S20 a corresponding signal to the gateway node GGSN 20 representing the communication network control element, which signal comprises a congestion indication.

The congestion indication is forwarded in steps S30 and S40 by network elements like BSC/RNC 40, 41 , SGSN 30 to the GGSN 20. The GGSN 20 instructs in step S50 the host element by the signaling mechanism chosen for this purpose about the need to offload traffic, i.e. it starts an offloading procedure. As a result, in step S55, the preference of the host may be changed to another network (communication path).

It is to be noted that in case the congestion is detected by a radio network controller like RNC 40 or by a serving node like SGSN 30, the initial signaling for the congestion indication starts from the corresponding level.

With regard to the signaling used for forwarding the congestion indication to the communication network control element, different kinds of signaling may be used. For example, in the network structure on which Fig. 2 is based, the following signals may be used to be passed through the network:

- In case the congestion is detected at a network part of a serving gateway or the like

(SGW, SGSN), the congestion indication to the gateway (PGW, GGSN) may be forwarded e.g. by using a GTP protocol based signaling, that would send IP layer message to the host for indicating offloading;

- In case the congestion is detected at a network part of a radio network controller (BSC, RNC, MME), the congestion indication may be indicated to the serving gateway (SGW,

SGSN) that would then indicate it further to the gateway (PGW, GGSN), that would send IP layer message to the host for indicating offloading;

- In case the congestion is detected at a network part of a base station (BS, eNB), the congestion indication in the cell may be indicated to a radio network controller which would then pass the information via the serving gateway to the gateway node, that would send IP layer message to the host for indicating offloading.

- In case the congestion is detected at a network part of a gateway, the gateway node triggers sending of IP layer offloading request to the host directly.

According to a further example of an embodiment of the invention, it is possible that the communication system is not equipped to detect congestion at certain levels. For example, it is possible that congestion detection is not conducted at a base station level, for example since a simpler design and deployment is desired. In such a case, according to an example of embodiments of the invention, a higher level network element is configured to detect a congestion at a network part in a downlink direction, and inform the gateway node accordingly. For example, when the congestion occurs on the base station level but is not detectable, the closest entity to user equipment that can detect congestion may be e.g. a radio network controller, or even a serving gateway, which would then send a congestion indication to the GGSN or the like.

Referring back to Fig. 2, it is possible that the congestion is released, i.e. that the congestion clears. Such a situation may be detected by the network element having detected the congestion state in step S10. That is, in step S60 the BS detects a congestion release state, and sends a congestion release indication to the GGSN in a similar manner to the communication network control element (GGSN 20) like in case of the congestion indication via a message path denoted by steps S70, S80 and S90. The GGSN 20 instructs in step S100 the host network element by the signaling mechanism chosen for this purpose about the stop of offloading procedure. That is, the previous offloading indication or setting is removed by sending another information for setting a new preference for the selection of an access network or the like. For example, a normal indication of preferences regarding communication paths is sent to the UE 10. As a result, in step S105, the preference of the host may be changed back to the defaul network (communication path).

As indicated above, while the scenario illustrated in Fig. 2 is related to a case where traffic on a cellular network is to be offloaded to a to another network, such as a WiFi network, similar steps are applicable to a scenario where congestion occurs in a (managed) WiFi network and traffic is to be offloaded to the cellular network. In such a case hosts are guided to offload traffic to other networks - this time from WiFi to cellular.

Fig. 3 shows a flowchart illustrating a processing executed in a communication network element according to examples of embodiments of the invention. Specifically, Fig. 3 describes a procedure for detecting a congestion state and informing the communication network control element to trigger an offloading procedure.

In step S200, a traffic congestion state in a communication network part is detected. The communication network part may be on the same level or in a downlink direction of the network element detecting the congestion.

In step S210, it is decided whether offloading of traffic is to be requested from the communication network part, i.e. whether or not a specified level of congestion is determined.

If the decision in step S210 is negative, congestion state detection in step S200 is continued.

If the decision in step S210 is affirmative, a congestion indication comprising an information element indicating a request for initializing a traffic offloading procedure to another communication path is prepared and transmitted to the communication network control element (e.g. a gateway network element, for example a GGSN or the like) in step S220.

It is to be noted that the decision in step S210 may be based, for example, on a determination of a level of congestion (e.g. in percent), and to check whether this level exceeds a threshold, or the like.

In step S230, which is based on a detection of a congestion level in the communication network part like in step S200 (but not shown in Fig. 3), it is decided whether or not the traffic congestion state is released. The decision in step S230 may be based on a similar procedure like step S210.

If the decision in step S230 is negative, the detection of the congestion state and the decision about the release thereof is repeated.

If the decision in step S230 is affirmative, a congestion release indication comprising an information element indicating that the traffic offloading procedure to another

communication path can be stopped is prepared and sent to the communication network control element(e.g. a gateway network element, for example a GGSN or the like) in step S240.

Fig. 4 shows a flowchart illustrating a processing executed in a communication network control element, such as a GGSN, according to examples of embodiments of the invention. Specifically, Fig. 4 describes a procedure for deciding on executing an offloading procedure and for informing the host network element accordingly.

In step S300, it is determined, on the basis of a traffic congestion state of a

communication network part, whether traffic offloading is to be initialized. For example, the communication network control element detects a congestion state on its own network level, or receives a congestion indication from another network element.

In step S310, in case a decision is made that no offloading is to be triggered, the process returns to step S300.

Otherwise, in case in step S310 a decision is made that offloading procedure is to be triggered, in step S320, an offloading indication is prepared and transmitted to a host network element in the communication network part where congestion is detected. The offloading indication may comprise an information element that triggers the host network element to seek for a possibility to offload traffic, i.e. to change to another communication path, wherein it is also possible to directly indicate the type of the other communication path (i.e. identify which other communication network is to be used, like WiFi or the like).

In step S330, which is based on a decision regarding a necessity to conduct an offloading procedure based on a congestion state in the communication network part like in step S300 (but not shown in Fig. 4), it is decided whether or not the offloading procedure can be stopped, e.g. because the traffic congestion state is released.

If the decision in step S330 is negative, the procedure repeats step S330.

If the decision in step S330 is affirmative, an indication is sent to the host network element to stop offloading, i.e. to use a normal communication path being set by default, or the like.

In the following, further examples of embodiments of the invention are described.

According to a further example of an embodiment of the invention, a communication network control element, such as a gateway node, may choose to send offloading indication to other hosts (UEs) known to be present at same area from where congestion notification was received. For example, in case a congestion occurs at a level of a SGSN, this is indicated to the gateway node, e.g. in one GTP session, i.e. that UE traffic should start to be offloaded. The communication network control element then sends a corresponding signal, e.g. in the form of an RA with offloading indication, to all host network elements being located under the SGSN. Thus, it is tried that some of the host network elements (UEs) offload, as far as these UEs can establish a connection to the other network system. In an alternative example of embodiments of the invention, the communication network control element sends the offloading indication only to those host network elements that receive an explicit offloading request from the SGSN.

That is, according to a corresponding example of embodiments of the invention, it is possible to select one or more host network elements being located in the area where the congestion is detected for receiving the offloading indication.

According to another example of an embodiment of the invention, the network element sending the congestion indication to the communication network control element includes additional information besides a mere indication of whether or not a congestion is detected. For example, the access technology, such as a RAT type, of the congested network part may be sent to the communication network control element so that a more informed offloading decision can be made. For example, information that the RAT where congestion happened is a 3GPP access, a trusted non-3GPP, or like this may be sent to the communication network control element with the congestion indication. When considering the RAT type, the communication network control element may, for example, come to the decision that offloading is not to be conducted, even in case congestion is detected.

According to a further example of embodiments of the invention, e.g. in case a base station sends the congestion indication, lu-PS signaling may be used. The next network entity, e.g. the SGSN, sends the congestion indication in a GTP signaling. That is, in the GTP signaling the SGSN indicates to the GGSN that the UE (handset) is in a congested cell. The GGSN sends, after learning about the congestion via GTP, the offloading indication with an IP-layer solution back to the UE. For example, RA signaling with a further information element is used. As indicated above, the GGSN may also send the offloading indication to other UEs which may be located in the same cell. It is to be noted that according to this example of embodiments of the invention, signaling load toward the UEs due to offloading indication does not increase significantly, since a signaling like RA is anyway sent periodically.

According to a still further example of embodiments of the invention, in order to save in signaling and battery costs, the communication network control element may postpone sending of offloading guidance message (i.e. offloading indication) to a UE which is not active, i.e. in an idle state or the like. The offloading indication may be thus sent to the UE right after the UE becomes active again. In other words, a host activity level determination may be conducted to determine an activity state of the host network element (UE). The transmission of the offloading indication to the host network element being inactive or idle is then postponed.

According to a further example of an embodiment of the invention, in case a GTP Control Plane message is used for sending a congestion indication to the communication network control element, a new message type indicating congestion on cell may be used. For example, in case a corresponding message is based on one defined in 3GPP specification TS 29.274, the message may use a generic header format as defined therein. An example thereof is illustrated in the following table 1.

Table V.

Bits

Octets 8 7 6 5 4 3 2 1

1 Version P T Spare Spare Spare

2 Message Type

3 Message Length (1^3t Octet)

4 Message Length (2^nd Octet)

m to If T flag is set to 1 , then TEID shall be placed into octets 5- k(m+3) 8. Otherwise, TEID field is not present at all.

n to (n+2) Sequence Number

(n+3) Spare

Figure 5.1-1 : General format of GTPv2 Header for Control Plane

According to the present example of embodiments of the invention, the message, for transporting the congestion indication, needs a new message type. Additionally, a new Information Element is required to contain the actual congestion indication. Hence the overall structure may look as indicated in the following table 2:

Table 2:

Bits

Octets 6 5 4

|l to m GTP-C header

m+1 to n Zero or more Information Element(s)

Figure 5.6-1: GTP-C Header followed by subsequent Information Elements

And the new Information Element may follow generic format as indicated in the following table 3:

Table 3:

Figure 8.2-1 : Information Element Format

Here, according to the present example of embodiments of the invention, for defining the congestion, the following definitions are used:

Type = to be defined (e.g. 162 is currently next free value)

IE specific data = may be an 8-bit value from 0-100 to indicate percentage level of congestion (for allowing additional intelligence on side of the gateway), or just Boolean value indicating offloading request Yes/No, or some other similar logic. Also "source RAT technology" type may be included to help the communication network control element for offloading decision making (if the congested access type is actually WLAN such as in trusted 3GPP access case, it may (or may not) be of very little use to guide user equipment to offload to WLAN). According to a further example of embodiments of the invention, the communication network control element may send offloading indications only to those connections that are "best effort" in nature. For connections with guaranteed quality of service or a high priority traffic class, it may be not preferred to send an offloading indication (for example, in case better quality of service is purchased or a connection is used that requires a higher quality of service, such as Voice over IP, then it may be preferable to avoid offloading for such connections).

Fig. 5 shows a block circuit diagram of a communication network element including processing portions conducting functions according to examples of embodiments of the invention. Specifically, in Fig. 5, a block circuit diagram illustrating a configuration of a communication network element, such as a RNC, BSC, MME, SGSN, etc., is shown, which is configured to implement functions for detecting a congestion state and sending a congestion indication to the communication network control element, and thus of the processing as described in connection with the examples of embodiments of the invention according to Fig. 3.

It is to be noted that the communication network element shown in Fig. 5 may comprise several further elements or functions besides those described herein below, which are omitted herein for the sake of simplicity as they are not essential for understanding the invention. Furthermore, even though reference is made to communication network element like an BSC etc., the communication network element may be also another device having a similar function, such as a modem chipset, a chip, a module etc., which can also be part of a communication network element or attached as a separate element to a communication network element, or the like. Moreover, it is to be noted that a communication network element according to examples of embodiments of the invention does not need to comprise all of the processing portions described below, as long as the main functionality regarding the congestion indication and offloading procedures can be executed.

The communication network element 100 may comprise a processing function or processor 110, such as a CPU or the like, which executes instructions given by programs or the like related to the power control. The processor 1 10 may comprise one or more processing portions dedicated to specific processing as described below, or the processing may be run in a single processor. Portions for executing such specific processing may be also provided as discrete elements or within one or more further processors or processing portions, such as in one physical processor like a CPU or in several physical entities, for example. Reference sign 120 denotes interface or transceiver or input/output (I/O) units connected to the processor 110. The I/O units 120 may be used for communicating with elements of the cellular network, such as a host network element like a UE, or a communication network control element like a GGSN or the like. The I/O units 120 may be a combined unit comprising communication equipment towards several network elements, or may comprise a distributed structure with a plurality of different interfaces for different network elements. Reference sign 130 denotes a memory usable, for example, for storing data and programs to be executed by the processor 1 10 and/or as a working storage of the processor 110.

The processor 110 is configured to execute processing related to the above described congestion detection and indication. In particular, the processor 110 comprises a sub- portion 11 10 as a processing portion which is usable as a congestion state detector. Furthermore, the processor 1 10 comprises a sub-portion 1 120 as a processing portion which is usable for preparing and transmitting the congestion indication. Moreover, the processor 110 may comprise a sub-portion 1 130 as a processing portion which is usable for determining a congestion level (e.g. in percent). Furthermore, the processor 110 may comprise a sub-portion 1140 as a processing portion which is usable for determining a congestion release state. Moreover, the processor 110 may comprise a sub-portion 1150 as a processing portion which is usable for preparing and transmitting the congestion release indication.

In Fig. 6, a block circuit diagram illustrating a configuration of a communication network control element, such as of GGSN 20, is shown, which is configured to implement the processing as described in connection with the examples of embodiments of the invention according to Fig. 4, for example.

It is to be noted that the communication network control element shown in Fig. 6 may comprise several further elements or functions besides those described herein below, which are omitted herein for the sake of simplicity as they are not essential for understanding the invention.

Furthermore, even though reference is made to a gateway element like a GGSN, the communication network control element may be also another device having a similar function, such as a modem chipset, a chip, a module etc., which can also be part of a gateway or attached as a separate element to a gateway, or the like. Moreover, it is to be noted that a network element according to examples of embodiments of the invention does not need to comprise all of the processing portions described below, as long as the main functionality regarding the congestion indication and offloading procedures can be executed.

The communication network control element 200 may comprise a processing function or processor 210, such as a CPU or the like, which executes instructions given by programs or the like related to the power control. The processor 210 may comprise one or more processing portions dedicated to specific processing as described below, or the processing may be run in a single processor. Portions for executing such specific processing may be also provided as discrete elements or within one or more further processors or processing portions, such as in one physical processor like a CPU or in several physical entities, for example. Reference sign 220 denotes interfaces or transceivers or input/output (I/O) units connected to the processor 210. The I/O units 220 may be used for communicating with network elements of the communication network, such as a SGSN or a UE. The I/O units 220 may be a combined unit comprising communication equipment towards several of the network element in question, or may comprise a distributed structure with a plurality of different interfaces for each network element in question. Reference sign 230 denotes a memory usable, for example, for storing data and programs to be executed by the processor 210 and/or as a working storage of the processor 210.

The processor 210 is configured to execute processing related to the above described congestion determination and offloading triggering. In particular, the processor 210 comprises a sub-portion 21 10 as a processing portion which is usable as a determiner for determining whether offloading is to be initialized, e.g. based on a congestion state. Furthermore, the processor 210 comprises a sub-portion 2120 as a processing portion which is usable for processing information used for deciding on an offloading initialization. Moreover, the processor 210 may comprise a sub-portion 2130 as a processing portion which is usable for preparing and transmitting an offloading indication towards one or more UEs. Furthermore, the processor 210 may comprise a sub-portion 2140 as a processing portion which is usable for determining an activity level of hosts (used for postponing transmission of the offloading indication). Moreover, the processor 210 may comprise a sub-portion 2150 as a processing portion which is usable for conducting a processing related to stop the offloading procedure, i.e. for deciding on a stop of the offloading procedure and for preparing and transmitting the corresponding indication.

In the following, in connection with Figs. 7 to 10, implementation examples of embodiment of the invention are shown in a network structure similar to that of Fig. 1. It is to be noted that for the sake of simplicity network elements being equivalent to those described in connection with Fig. 1 are not described in greater detail again.

Fig. 7 illustrates a case where cells of the cellular communication network have different congestion states. Specifically, cells indicated by„A" have a (high) congestion level, cells indicated by„B" are only slightly congested (i.e. in an acceptable level), and cells indicated by„C" are not congested. Also shown in Fig. 7 are locations where a moving UE 10 receives an offloading indication or an indication to stop offloading. Specifically, a down- arrow shows a cell where the network triggers sending of a message indicating offloading, e.g. by setting a low preference for cellular communication and a guidance to offload. An up-arrow shows a cell where the network triggers sending of a message with normal (or high) preference for cellular communication (i.e. stop of offloading). According to the present example, offloading is triggered only when the UE 10 enters to congested cell„A", and offloading guidance is removed only when the UE 10 is back at non-crowded cell„C".

It is to be noted that according to examples of embodiments of the invention a network operator may set parameters regarding the congestion level for changing the triggers (i.e. offload or stop offloading). That is, in the example of Fig. 7, the offloading indication (or the offloading stop indication) may be given already in a cell„B".

Fig. 8 illustrates a case where cells of the cellular communication network have different congestion states, and cells where also coverage is provided by areas 60 and 61 where another communication network, such as a WiFi network, is reachable. That is, a UE 10 moving in the network is able to conduct offloading when being in a WiFi coverage area 60 or 61 , wherein cellular access is not preferred.

It is to be noted that different types of UEs may be able to use different WiFi networks. Hence, it is possible that one UE being a in a congested cell conducts offloading while another UE does not, or that UEs have no access to WFi networks at all. In the scenario according to Fig. 8, the moving UE 10 is not able to start offloading when receiving the offloading indication, but only after moving to the next congested cell that happens to also be a WFi covered area. The UE 10 switches back to cellular when losing WiFi coverage, even in case the network has not yet indicated need to not offload (i.e. to stop offloading in cell„C").

Fig. 9 illustrates three time points in one cell with changing congestion states, wherein it may be assumed that the UE 10 is not moving. In the situation indicated by 1), the UE 10 is in a cell being not congested, and performs no offloading. In the situation indicated by 2), the cell gets first congested, e.g. due temporary presence of many UEs 1 1. Thus, the network indicates offload preference during congestion, and UE 10 being also in WiFi coverage area 60 conducts offloading. In the situation indicated by 3), several of the UEs 11 have left the cell so that no congestion state is present anymore. Hence, the network removes the indication once cell congestion state eases, and the UE may stop offloading.

Fig. 10 illustrates an example where a congestion state is detected on a higher level, e.g. an SGSN level. The SGSN 30 sends the congestion indication to the GGSN 20 and requests the GGSN to indicate offloading request to all UEs below the SGSN. The GGSN 20 sends the offloading indication to all (known) UEs in the communication network part for which the SGSN is responsible, i.e. where the congestion at the SGSN 30 has an effect. Of course, traffic offloading can be actually performed only by those UEs that happen to have e.g. WiFi coverage.

In the preceding examples of embodiments of the invention, an implementation in a cellular 3GPP based network is described. As indicated above, the examples of embodiments of the invention are also applicable in other network solutions. For example, in the case of an PMIP6 solutions, a MAG may send a Router Advertisement with offloading option after learning about cell congestion. The MAG may also inform LMA, e.g. in a Proxy Binding Update message. However, this is not necessary the MAG has access to same policy databases as LMA has.

Furthermore, in the preceding examples, for delivering the offloading indication to the host network element, an IP-based mechanism such as ICMPv6 and router advertisement are described. As an alternative example, it is also possible to use other mechanisms. For example, a mechanism based on ANDSF principles is implementable as a way to deliver offloading rules to host network elements. For example, in case the network operator intends to configure more long-standing offloading indications, ANDSF based signaling may be used.

According to a further example of an embodiment of the invention, there is provided an apparatus comprising a detecting processing means for detecting a traffic congestion state in a communication network part, and a transmitting processing means for sending to a communication network control element a congestion indication comprising an information element indicating a request for initializing a traffic offloading procedure to another communication path.

In addition, according to a still further example of an embodiment of the invention, there is provided an apparatus comprising an offloading determining means for determining, on the basis of a traffic congestion state, whether a traffic offloading in at least one communication network part is to be initialized, and an offloading requesting means for sending, in case the determination of the offloading determining means is affirmative, an offloading indication to a host network element in the at least one communication network part, wherein the offloading indication is adapted to trigger offloading of traffic to another communication path.

For the purpose of the present invention as described herein above, it should be noted that - an access technology via which signaling is transferred to and from a network element may be any technology by means of which a network element or sensor node can access another network element or node (e.g. via a base station or generally an access node). Any present or future technology, such as WLAN (Wireless Local Access Network), WiMAX (Worldwide Interoperability for Microwave Access), LTE, LTE-A, Bluetooth,

Infrared, and the like may be used; although the above technologies are mostly wireless access technologies, e.g. in different radio spectra, access technology in the sense of the present invention implies also wired technologies, e.g. IP based access technologies like cable networks or fixed lines but also circuit switched access technologies; access technologies may be distinguishable in at least two categories or access domains such as packet switched and circuit switched, but the existence of more than two access domains does not impede the invention being applied thereto,

- usable communication networks and transmission nodes may be or comprise any device, apparatus, unit or means by which a station, entity or other user equipment may connect to and/or utilize services offered by the access network; such services include, among others, data and/or (audio-) visual communication, data download etc.;

- a user equipment or communication network element may be any device, apparatus, unit or means by which a system user or subscriber may experience services from an access network, such as a mobile phone, personal digital assistant PDA, or computer, or a device having a corresponding functionality, such as a modem chipset, a chip, a module etc., which can also be part of a UE or attached as a separate element to a UE, or the like;

- method steps likely to be implemented as software code portions and being run using a processor at a network element or terminal (as examples of devices, apparatuses and/or modules thereof, or as examples of entities including apparatuses and/or modules for it), are software code independent and can be specified using any known or future developed programming language as long as the functionality defined by the method steps is preserved;

- generally, any method step is suitable to be implemented as software or by hardware without changing the idea of the invention in terms of the functionality implemented;

- method steps and/or devices, apparatuses, units or means likely to be implemented as hardware components at a terminal or network element, or any module(s) thereof, are hardware independent and can be implemented using any known or future developed hardware technology or any hybrids of these, such as a microprocessor or CPU (Central Processing Unit), MOS (Metal Oxide Semiconductor), CMOS (Complementary MOS), BiMOS (Bipolar MOS), BiCMOS (Bipolar CMOS), ECL (Emitter Coupled Logic), TTL (Transistor-Transistor Logic), etc., using for example ASIC (Application Specific IC

(Integrated Circuit)) components, FPGA (Field-programmable Gate Arrays) components, CPLD (Complex Programmable Logic Device) components or DSP (Digital Signal Processor) components; in addition, any method steps and/or devices, units or means likely to be implemented as software components may for example be based on any security architecture capable e.g. of authentication, authorization, keying and/or traffic protection;

- devices, apparatuses, units or means can be implemented as individual devices, apparatuses, units or means, but this does not exclude that they are implemented in a distributed fashion throughout the system, as long as the functionality of the device, apparatus, unit or means is preserved; for example, for executing operations and functions according to examples of embodiments of the invention, one or more processors may be used or shared in the processing, or one or more processing sections or processing portions may be used and shared in the processing, wherein one physical processor or more than one physical processor may be used for implementing one or more processing portions dedicated to specific processing as described,

- an apparatus may be represented by a semiconductor chip, a chipset, or a (hardware) module comprising such chip or chipset; this, however, does not exclude the possibility that a functionality of an apparatus or module, instead of being hardware implemented, be implemented as software in a (software) module such as a computer program or a computer program product comprising executable software code portions for

execution/being run on a processor;

- a device may be regarded as an apparatus or as an assembly of more than one apparatus, whether functionally in cooperation with each other or functionally

independently of each other but in a same device housing, for example.

As described above, there is provided a mechanism for triggering offloading in the case that a traffic congestion occurs in a network part. When a traffic congestion state in a communication network part is detected, a congestion indication comprising an information element indicating a request for initializing a traffic offloading procedure to another communication path is sent to a communication network control element. The communication network control element determines, on the basis of a traffic congestion state, whether a traffic offloading in a communication network part is to be initialized, and sends, in case the determination of the offloading determining portion is affirmative, an offloading indication to a host network element in the communication network part, wherein the offloading indication triggers offloading of traffic to another communication path.

Although the present invention has been described herein before with reference to particular embodiments thereof, the present invention is not limited thereto and various modifications can be made thereto.

Claims

1. An apparatus comprising

a detecting processing portion configured to detect a traffic congestion state in a communication network part, and

a transmitting processing portion configured to send to a communication network control element a congestion indication comprising an information element indicating a request for initializing a traffic offloading procedure to another communication path.

2. The apparatus according to claim 1 , further comprising

a determining processing portion configured to determine a level of congestion in the communication network part, and

a deciding processing portion configured to decide, on the basis of the determined level of congestion, whether traffic offloading at the communication network part is to be requested,

wherein the transmitting processing portion is configured to send the congestion indication in case the deciding processing portion decides that traffic offloading is to be requested.

3. The apparatus according to claim 1 or 2, wherein

the detecting processing portion is further configured to detect that the traffic congestion state is released, wherein the transmitting processing portion is configured to send to the communication network control element a congestion release indication comprising an information element indicating that the traffic offloading procedure to another communication path can be stopped.

4. The apparatus according to any of claims 1 to 3, wherein the detecting processing portion is configured to detect a traffic congestion at a communication network path being located in a downlink direction of the apparatus.

5. The apparatus according to any of claims 1 to 4, wherein the transmitting processing portion is configured to send with the congestion indication at least one of

access technology information indicating an access technology at the

communication network part where the traffic congestion occurs,

congestion level information indicating a level of the traffic congestion, recipient information indicating which terminal nodes are to be involved in the traffic offloading procedure, and

one of a traffic offloading request and a traffic offloading stop request.

6. The apparatus according to any of claims 1 to 5, wherein the apparatus is comprised in at least one of

an access network element, an access network control element, a core network control element, and a gateway network element.

7. A method comprising

detecting a traffic congestion state in a communication network part, and sending to a communication network control element a congestion indication comprising an information element indicating a request for initializing a traffic offloading procedure to another communication path.

8. The method according to claim 7, further comprising

determining a level of congestion in the communication network part, and deciding, on the basis of the determined level of congestion, whether traffic offloading at the communication network part is to be requested,

wherein the congestion indication is sent in case it is decided that traffic offloading is to be requested.

9. The method according to claim 7 or 8, further comprising

detecting that the traffic congestion state is released, and

sending, to the communication network control element, a congestion release indication comprising an information element indicating that the traffic offloading procedure to another communication path can be stopped.

10. The method according to any of claims 7 to 9, wherein in the detecting a traffic congestion at a communication network path being located in a downlink direction of the apparatus is detected.

11. The method according to any of claims 7 to 10, further comprising transmitting, with the congestion indication, at least one of access technology information indicating an access technology at the

communication network part where the traffic congestion occurs,

congestion level information indicating a level of the traffic congestion,

recipient information indicating which terminal nodes are to be involved in the traffic offloading procedure, and

one of a traffic offloading request and a traffic offloading stop request.

12. The method according to any of claims 7 to 1 1 , wherein the method is implemented ^' at least one of

13. An apparatus comprising

an offloading determining portion configured to determine, on the basis of a traffic congestion state, whether a traffic offloading in at least one communication network part is to be initialized, and

an offloading requesting portion configured to send, in case the determination of the offloading determining portion is affirmative, an offloading indication to a host network element in the at least one communication network part, wherein the offloading indication is adapted to trigger offloading of traffic to another communication path.

14. The apparatus according to claim 13, further comprising

a receiver configured to receive a congestion indication comprising an information element indicating a request for initializing a traffic offloading procedure to another communication path,

wherein the offloading determining portion is configured to determine that the traffic offloading is to be initialized when

the detecting processing portion detects a traffic congestion state in the communication network part, or

the receiver receives a congestion indication.

15. The apparatus according to claim 13 or 14, wherein in case the offloading determining portion determines that traffic offloading in the communication network part can be stopped, the offloading requesting part is configured to send an indication to the host network element to use a normal communication path being set by default in the at least one communication network part.

16. The apparatus according to any of claims 13 to 15, further comprising

selection processing portion configured to select one or more host network elements being located in the at least one communication network part as recipient for the offloading indication.

17. The apparatus according to any of claims 13 to 16, further comprising

an information processing portion configured to receive and process at least one of

access technology information indicating an access technology at the

communication network part where the traffic congestion occurs,

congestion level information indicating a level of the traffic congestion,

recipient information indicating to which host network elements the offloading indication is to be sent, and

one of a traffic offloading request and a traffic offloading stop request, wherein the information processing portion is further configured to determine, on the basis of the received information, whether or not the offloading indication is sent to the host network element, and to set parameters of an offloading procedure triggered by the offloading indication.

18. The apparatus according to any of claims 13 to 17, wherein

the offloading requesting portion is further configured to send the offloading indication to the host network element by using an Internet Protocol layer signaling.

19. The apparatus according to any of claims 13 to 18, wherein the offloading indication comprises an information element indicating a preference for a type of another communication path to which traffic is to be offloaded.

20. The apparatus according to any of claims 13 to 19, further comprising

a host activity level determining portion configured to determine an activity state of the host network element to which the offloading indication is to be sent, wherein the host activity level determining portion is further configured to cause the offloading requesting portion to postpone the transmission of the offloading indication to a host network element whose activity state is determined to be inactive or idle.

21. The apparatus according to any of claims 13 to 20, wherein the apparatus is comprised in a core network control element, in particular a gateway network element.

22. A method comprising

determining, on the basis of a traffic congestion state, whether a traffic offloading in at least one communication network part is to be initialized, and

sending, in case the determination of the traffic offloading is affirmative, an offloading indication to a host network element in the at least one communication network part, wherein the offloading indication is adapted to trigger offloading of traffic to another communication path.

23. The method according to claim 22, further comprising at least one of

detecting a traffic congestion state in a communication network part, and receiving a congestion indication comprising an information element indicating a request for initializing a traffic offloading procedure to another communication path, wherein it is determined that the traffic offloading is to be initialized when

a traffic congestion state in the communication network part is detected, or

a congestion indication is received.

24. The method according to claim 22 or 23, further comprising

determining that traffic offloading in the communication network part can be stopped, and sending an indication to the host network element to use a normal communication path being set by default in the at least one communication network part in case it is determined that traffic offloading can be stopped.

25. The method according to any of claims 22 to 24, further comprising

selecting one or more host network elements being located in the at least one communication network part as recipient for the offloading indication.

26. The method according to any of claims 22 to 25, further comprising receiving and processing at least one of

access technology information indicating an access technology at the communication network part where the traffic congestion occurs,

congestion level information indicating a level of the traffic congestion,

one of a traffic offloading request and a traffic offloading stop request,

and at least one of

determining, on the basis of the received information, whether or not the offloading indication is sent to the host network element, and

setting parameters of an offloading procedure triggered by the offloading indication.

27. The method according to any of claims 22 to 26, further comprising

sending the offloading indication to the host network element by using an Internet Protocol layer signaling.

28. The method according to any of claims 22 to 27, wherein the offloading indication comprises an information element indicating a preference for a type of another communication path to which traffic is to be offloaded.

29. The method according to any of claims 22 to 28, further comprising

determining an activity state of the host network element to which the offloading indication is to be sent, and

causing to postpone the transmission of the offloading indication to a host network element whose activity state is determined to be inactive or idle.

30. The method according to any of claims 22 to 29, wherein the method is implemented in a core network control element, in particular a gateway network element.

31. A computer program product for a computer, comprising software code portions for performing the steps of any of claims 7 to 12 or 22 to 30 when said product is run on the computer.

32. The computer program product according to claim 31 , wherein

the computer program product comprises a computer-readable medium on which said software code portions are stored, and/or

the computer program product is directly loadable into the internal memory of the computer and/or transmittable via a network by means of at least one of upload, download and push procedures.