WO2016007050A1

WO2016007050A1 - Multipath transmission control protocol

Info

Publication number: WO2016007050A1
Application number: PCT/SE2014/050865
Authority: WO
Inventors: Jari Vikberg; Michael Eriksson; Oscar Zee
Original assignee: Telefonaktiebolaget L M Ericsson (Publ)
Priority date: 2014-07-07
Filing date: 2014-07-07
Publication date: 2016-01-14

Abstract

It is disclosed a multipath transmission control protocol, MPTCP,capable system is adapted to reducecontrol signaling in the network and/or in a MPTCP capable UE(702), when a MPTCP capable UE is entering a coverage area of a second radio access type, RAT, and/orto reduce disconnection time for the MPTCP capable UE (702), when the MPTCP capable UE is about to leave the coverage area of the second RAT, when the second RAT has priority over the first RAT. In addition to the MPTCP capable UE, this disclosure further comprises a controller of the second RAT (706), a MPTCP capable network proxy node(708), and a MPTCP capable network system. Also, methods and computer program in the respective arrangement are also presented.

Description

MULTIPATH TRANSMISSION CONTROL PROTOCOL

TECHNICAL FIELD

This disclosure relates to multipath transmission control protocol (MPTCP). In more particular, it relates to handling of a MPTCP session by a MPTCP capable user equipment (UE), a controller of a second radio access type, RAT, a MPTCP capable network proxy node, and by a MPTCP capable network system. This disclosure also relates to methods therein and computer programs therefore.

BACKGROUND

Most hosts today are multi-homed. Hence, they have multiple paths for connectivity via one or more access technologies. Regular transmission control protocol (TCP)/Internet protocol (IP) communications restrict these multi-homed hosts to use only one of the available interfaces/paths per session, where path is defined as an IP address pair of the source and destination of the path. Internet engineering task force (IETF) is looking into a mechanism, which uses multiple paths between communicating peers simultaneously during a communication session. Request for comments (RFC) 6824, Jan. 2013 proposes a set of extensions to traditional TCP for multipath operations when multiple addresses are available. This protocol is referred to as MPTCP.

The advantages of using multiple paths concurrently comprise:

- Improve network resource utilization, e.g., increase bandwidth due to resource pooling) - Improve user experience through higher throughput

- Allows failover from one interface to another, e.g., mobile client

- Allows a single data connection to use several interfaces simultaneously

Figure 1 schematically presents a usage scenario for MPTCP, in which two communicating hosts A and B are multi-homed and multi-addressed. Each host provides two separate connections to the Internet offering four different paths between them, Al-B l, A1-B2, A2-B 1 and A2-B2.

A traditional TCP connection between the hosts A and B will make use of only one of the available paths whereas MPTCP connection makes use of all the four available paths between hosts A and B. An MPTCP connection is similar to a regular TCP connection and is defined in RFC 6824 as: a set of one or more subflows, over which an application can communicate between two hosts. A subflow is defined in RFC 6824 as: A flow of TCP segments operating over an individual path, which forms part of a larger MPTCP connection. A subflow is started and terminated similar to a regular TCP connection.

MPTCP is an end-to-end protocol which requires both hosts to support MPTCP to benefit from MPTCP. Since, MPTCP is still in its early stage of deployment, probabilities that every host on the Internet supports MPTCP are very low. To overcome this problem and benefit from MPTCP even though both communicating hosts do not support MPTCP, an MPTCP proxy may be used to convert MPTCP flows to TCP and vice versa.

Figure 2 schematically presents a scenario in which a UE is MPTCP capable whereas a server, corresponding to Host B, is MPTCP unaware.

The MPTCP capable UE, corresponding to Host A, is controlled by the operator and sets up several

MPTCP subflows to the MPTCP proxy placed in the operator's network. This proxy in turn sets up a single TCP flow to a server on the Internet, corresponding to Host B, which is not MPTCP capable. In the described scenario, the UE which supports MPTCP can still get the benefits of MPTCP although the server at the other end is not aware of MPTCP.

One principle of multipath TCP is to aggregate a set of TCP connections for example over different wireless interfaces such as 3^rd generation partnership program (3GPP) and wireless local area network accesses, such as Wi-Fi, or even different simultaneous 3GPP accesses. MPTCP has one main flow and multiple subflows and is capable of distributing load on all interfaces. As the multiplexing of different connections is on TCP level it allows separate congestion control for each subflow.

Figure 3 shows the differences between standard TCP and MPTCP protocol stacks. The application interface, i.e., the socket application programming interface (API) is unchanged and the main changes are between this API and the IP-layer. MPTCP provides the possibility to fully and maximally utilize different TCP subflows. For example, in the case of one TCP subflow on 3GPP access and another one on a wireless local area network (WLAN) such as Wi-Fi access, the total throughput may be the sum of these subflows.

Figure 4 shows a user plane protocol architecture example for the case when MPTCP would be utilizing LTE and WLAN/Wi-Fi simultaneously. The LTE subflow is visualized to the left in the figure, whereas the Wi-Fi subflow is visualized to the right in the figure. Additional protocol layers may also be included, for example an 802.11 logical link control (LLC) protocol between the protocol layers IP2 and 802.11 medium access control (MAC) (not shown in Figure 4).

Figure 5 shows an example of a MPTCP system in which a UE is simultaneously connected to both LTE and Wi-Fi/WLAN and where a MPTCP subflow is present for each radio access type. The application in the UE has opened up one TCP socket and is sending a "stream of bytes" on the internal API. The MPTCP layer may contain different functionality, one of which may be called MPTCP scheduler, has established two different TCP subflows, subflow 1 via WLAN/Wi— Fi, to the left in the UE, and subflow 2 via LTE, to the right in the UE. Both these subflows are in this example towards a MPTCP proxy node that further communicates with another server using plain TCP, on the right-hand side in the figure.

The MPTCP scheduler is the function that decides how the different packets are mapped to the two subflows. In this example, the MPTCP scheduler is applying "round-robin" scheduling, by alternating between subflow 1 and 2, i.e., first TCP segment is sent on subflow 2, second on subflow 1, third again on subflow 2 etc. Another example is that a MPTCP scheduler uses the subflow with the shortest round- trip time.

MPTCP bring two general advantages, one being that "seamless session continuity at mobility" is enabled, and the other advantage is that throughput aggregation is enabled.

The MPTCP "seamless session continuity at mobility" functionality may also be called "MPTCP session continuity". The basic principle for this functionality is the concepts of "main" and "backup" subflows. The "main" subflow is normally established first and used for data transmission while the "backup" subflow is established after (or in parallel) to the "main" subflow and not used for data transmission as long as the "main" subflow is operational. If the "main" subflow fails, then the "backup" subflow becomes the "main" subflow and all transmission is moved to the "backup" subflow, in its new status as the "main subflow". A similar approach applies for the release of the subflows when this functionality is used. This means that when the "main" subflow is released, the related "backup" subflow is also released.

When using MPTCP "seamless session continuity at mobility", two drawbacks have been identified.

During a MPTCP connection to setup, add or remove a subflow, or a connection to close, control signal exchange will occur on the subflow, even if the subflow is used as "backup path" for seamless session continuity at mobility" and no data will be transmitted on the backup subflow unless there is problem with the main subflow due to e.g. changed conditions caused by mobility.

If a 3GPP access is used for a backup subflow, and although no data is transmitted, state changes occur on 3GPP side, e.g. for LTE state transitions between RRC CONNECTED and RRC IDLE will occur, where R C stands for radio resource control. This may happen for example due to establishment and release of a backup subflow on 3GPP access. An additional example is if the backup subflow is maintained a long time as then even a possible keep-alive signaling on the backup subflow will have similar effect. This results in resource allocation and additional signaling on 3GPP access. This is a drawback since no data may be transmitted on the backup subflow.

In the case a UE is moving and the UE is leaving Wi-Fi for 3GPP access, and the UE is having a "main" subflow on Wi-Fi and possibly a "backup" subflow on 3GPP access, there will be a disconnection time as the MPTCP needs to detect an outage of the Wi-Fi subflow before traffic is moved to 3GPP subflow. The connection time may be even longer in a scenario when a 3GPP subflow has been setup a for a long time, and the UE in the 3GPP access has entered idle state due to inactivity on the 3GPP subflow (and inactivity related to other traffic as well), as in this case the UE needs to also enter "connected" state in the 3GPP access.

Figure 6 presents an exemplary MPTCP capable network having a MPTCP capable network proxy node 62, a controller of a first radio access type (RAT) 61, a controller of a second RAT, and a MPTCP capable user equipment (UE) 68. There is hence a need for a solution addressing one or more of these issues as discussed above.

SUMMARY

It is an object of exemplary embodiments to address at least some of the issues outlined above, and this object and others are achieved by a multipath transmission control protocol (MPTCP) capable user equipment (UE), and controller of a second radio access type (RAT), a MPTCP capable network proxy node, as well as a MPTCP capable network system, and methods and computer programs therein, according to the appended independent claims, and by embodiments of the disclosure according to the dependent claims.

According to one aspect, the present disclosure provides a method in a controller of a second radio access type (RAT) for controlling MPTCP subflows, and for controlling a UE radio access network state in a first radio access type, RAT. MPTCP session continuity is applied for the UE, connected to a MPTCP capable network proxy node. The UE is connected to a controller of a first RAT, with an active MPTCP subflow. The method comprises deciding that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT. The method also comprises sending an indication to the MPTCP capable network proxy node when the UE is allowed to access the second RAT, enabling reduction of control signaling.

According to another aspect, the present disclosure provides a method in a MPTCP capable network proxy node for controlling of MPTCP subflow establishment and release, and for controlling a UE radio access network state in a first radio access type, RAT. MPTCP session continuity is applied for a UE connected to the MPTCP capable network proxy node, wherein the UE is connected to a controller of a first RAT, with an active MPTCP subflow. The method comprises receiving an indication from a controller of a second RAT or from the UE, when the controller of the second RAT has decided that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT. The method also comprises triggering an MPTCP control action to reduce control signaling in the network and/or the UE, based on the received indication.

According to another aspect, the present disclosure provides a method in a MPTCP capable UE for which a first RAT has a lower priority than a second RAT. The method comprises when initiating a MPTCP session between the UE and a MPTCP capable network proxy node, if only said first RAT is available to the UE, initiating a first RAT subflow. If only said second RAT is available to the UE, initiating a second RAT subflow, and if both the first and the second RAT are available to the UE, initiating the second RAT. The method comprises when a MPTCP session comprising a first RAT subflow is already initiated between the UE and the MPTCP capable network proxy node, initiating a second RAT subflow when the second RAT becomes available to the UE.

According to another aspect, the present disclosure provides a method in a MPTCP capable network system, for controlling MPTCP subflow establishment and release, and for controlling a UE radio access network state in a first radio access type, RAT. As above, MPTCP session continuity is applied for a UE connected to a MPTCP capable network proxy node, wherein the UE is connected to a controller of a first RAT with an active MPTCP subflow. The method comprises deciding by a controller of a second RAT that the UE is allowed access to the second RAT based on radio level and/or traffic load level information on both first and second RAT. The method also comprises sending by the controller of the second RAT or by the UE, to the MPTCP capable network proxy node, an indication, when the controller of the second RAT has decided that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT. In addition, the method comprises triggering by the MPTCP capable network proxy node an MPTCP control action to reduce control signaling in the network and/or the UE, based on the received indication.

According to another aspect, the present disclosure provides a method in a controller of a second RAT for controlling MPTCP subflows, and for controlling a UE radio access network state in a first radio access type, RAT, when MPTCP session continuity is applied for a user equipment, UE, connected to a MPTCP capable network proxy node. The UE is connected to a controller of a second RAT, with an active MPTCP subflow. The method comprises detecting that the UE performance has decreased beyond a first threshold. The method also comprises sending to a MPTCP capable network proxy node an indication that the UE performance has decreased beyond the first threshold.

According to yet another aspect, the present disclosure provides a method in a MPTCP capable network proxy node for controlling MPTCP subflows, and for controlling a UE radio access network state in a first radio access type, RAT. MPTCP session continuity is applied for the UE being connected to the MPTCP capable network proxy node, wherein the UE is connected to a controller of a second RAT with an active MPTCP subflow. The method comprises receiving an indication from a controller of a second RAT. The method also comprises triggering an MPTCP control action to reduce control signaling in the UE, based on the received indication.

According to another aspect, the present disclosure provides a method in a MPTCP capable UE, for controlling MPTCP subflows, and for controlling a UE radio access network state in a first radio access type, RAT. As above, MPTCP session continuity is applied for the UE connected to a MPTCP capable network proxy node, wherein the UE is connected to a controller of a second RAT with an active MPTCP subflow. The method comprises receiving an indication that a MPTCP subflow over a first RAT to the MPTCP capable network proxy node is setup. The method also comprises receiving a trigger from the

MPTCP capable network proxy node triggering the release of the MPTCP subflow over the second RAT; and/or releasing the second RAT.

According to still yet another aspect, the present disclosure provides a method in a MPTCP capable network system, for controlling MPTCP subflows, and for controlling a UE radio access network state in a first radio access type, RAT. As above, MPTCP session continuity is applied for a UE connected to a MPTCP capable network proxy node, wherein the UE is connected to a controller of a second RAT with an active MPTCP subflow. The method comprises detecting by a controller of a second RAT that the UE performance has decreased to a threshold. The method further comprises sending by the controller of the second RAT, to the MPTCP capable network proxy node, an indication, when the controller of the second RAT has detected that the UE performance has decreased to the threshold, and the MPTCP capable network proxy node receiving the indication from the controller of the second RAT. In addition, the method also comprises triggering by the MPTCP capable network proxy node an MPTCP control action to reduce control signaling in the network, based on the indication as received by the MPTCP capable network proxy node.

According to still yet another aspect, the present disclosure provides a controller of the second RAT capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a UE connected to the MPTCP capable network proxy node, and where the UE is connectable to a controller of a RAT, with an active MPTCP subflow. The controller of the second RAT comprises a processor and a memory storing a computer program comprising computer program code which when run in the processor, causes the controller of the second RAT to decide that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT. Also, when the computer program code is run in the processor, it causes the controller of the second RAT to send an indication to the MPTCP capable network proxy node when the UE is allowed to access the second RAT, enabling reduction of control signaling.

According to still yet another aspect, the present disclosure provides a computer program having computer readable program code which when run in a processor of a controller of the second RAT, capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first RAT, where MPTCP session continuity is applied for a UE connected to the MPTCP capable network proxy node, and where the UE is connectable to a controller of a first radio access type, RAT, with an active MPTCP subflow, causes it to decide that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT. When the program code is run in the processor the program code further causes it to send an indication to the MPTCP capable network proxy node when the UE is allowed to access the second RAT, enabling reduction of control signaling.

According to still yet another aspect, the present disclosure provides a controller of the second

RAT, capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a UE connected to the MPTCP capable network proxy node, and where the UE is connectable to a controller of a first radio access type, RAT, with an active MPTCP subflow, which MPTCP capable network proxy node further is adapted to decide that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT, and to send an indication to the MPTCP capable network proxy node when the UE is allowed to access the second RAT, enabling reduction of control signaling.

According to still yet another aspect, the present disclosure provides a MPTCP capable network proxy node that is capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a UE connected to the MPTCP capable network proxy node, and where the UE is connectable to a controller of a first radio access type, RAT, with an active MPTCP subflow. The network proxy node comprises a processor and a memory storing a computer program comprising computer program code which when run in the processor, causes the MPTCP capable network proxy node to receive an indication from a controller of a second RAT or from the UE, when the controller of the second RAT has decided that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT. Also, when the computer program code is run in the processor, it causes the MPTCP capable network proxy node to trigger an MPTCP control action to reduce control signaling in the network and/or the UE, based on the received indication.

According to still yet another aspect, the present disclosure provides a computer program having computer readable program code which when run in a processor of a MPTCP capable network proxy node, capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first RAT, where MPTCP session continuity is applied for a UE connected to the MPTCP capable network proxy node, and where the UE is connectable to a controller of the first radio access type, RAT, with an active MPTCP subflow, causes it to receive an indication from a controller of a second RAT or from the UE, when the controller of the second RAT has decided that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT. When the program code is run in the processor the program code further causes it to trigger an MPTCP control action to reduce control signaling in the network and/or the UE, based on the received indication.

According to still yet another aspect, the present disclosure provides a MPTCP capable network proxy node, capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first RAT, where MPTCP session continuity is applied for a UE connected to the MPTCP capable network proxy node, and where the UE is connectable to a controller of a first RAT, with an active MPTCP subflow, which MPTCP capable network proxy node further is adapted to receive an indication from a controller of a second RAT or from the UE, when the controller of the second RAT has decided that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT. This MPTCP capable network proxy node is also adapted to trigger an MPTCP control action to reduce control signaling in the network and/or the UE, based on the received indication.

According to still yet another aspect, the present disclosure provides a MPTCP capable UE for which a first RAT has a lower priority than a second RAT. The UE comprises a processor and a memory storing a computer program comprising computer program code which when run in the processor causes the UE to:

- when initiating a MPTCP session between the UE and a MPTCP capable network proxy node:

- initiate a first RAT subflow, if only said first RAT is available to the UE,

- initiate a second RAT subflow, if only said second RAT is available to the UE; and

- initiate the second RAT, if both the first and the second RAT are available to the UE; and

- when a MPTCP session comprising a first RAT subflow is already initiated between the UE and the MPTCP capable network proxy node:

- initiate a second RAT subflow when the second RAT becomes available to the UE.

According to still yet another aspect, the present disclosure provides a computer program having computer readable program code which when run in a processor of the MPTCP capable UE for which a first RAT has a lower priority than a second RAT, causes the UE to:

- initiate a first RAT subflow, if only said first RAT is available to the UE,

According to still yet another aspect, the present disclosure provides a MPTCP capable UE, for which a first RAT has a lower priority than a second RAT, which UE further is adapted to:

- initiate a first RAT subflow, if only said first RAT is available to the UE,

- initiate a second RAT subflow, if only said second RAT is available to the UE; and - initiate the second RAT, if both the first and the second RAT are available to the UE; and

According to still yet another aspect, the present disclosure provides a MPTCP capable network system that is capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applicable for a UE connectable to a MPTCP capable network proxy node, and where the UE is connectable to a controller of the first RAT, with an active MPTCP subflow. The system comprises a processor and a memory storing a computer program comprising computer program code which when run in the processor, causes the MPTCP capable network system to decide by a controller of a second RAT that the UE is allowed access to the second RAT based on radio level and/or traffic load level information on both first and second RAT. When the program code is run in the processor, it further causes the MPTCP capable network system to send by the controller of the second RAT or by the UE, to the MPTCP capable network proxy node, an indication, when the controller of the second RAT has decided that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT. In addition, when the program code is run in the processor, it also causes the MPTCP capable network system to trigger by the MPTCP capable network proxy node an MPTCP control action to reduce control signaling in the network and/or the UE, based on the received indication.

According to still yet another aspect, the present disclosure provides a computer program having computer readable program code which when run in a processor of a MPTCP capable network system capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first

RAT, where MPTCP session continuity is applicable for a UE connectable to a MPTCP capable network proxy node, and where the UE is connectable to a controller of a first RAT, with an active MPTCP subflow, causes it to decide by a controller of a second RAT that the UE is allowed access to the second RAT based on radio level and/or traffic load level information on both first and second RAT. When the program code is run in the processor, it further causes the MPTCP capable network system to send by the controller of the second RAT or by the UE, to the MPTCP capable network proxy node, an indication, when the controller of the second RAT has decided that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT. In addition, when the program code is run in the processor, it also causes the MPTCP capable network system to trigger by the MPTCP capable network proxy node an MPTCP control action to reduce control signaling in the network and/or the UE, based on the received indication.

According to still yet another aspect, the present disclosure provides a MPTCP capable network system, capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applicable for a UE connectable to a MPTCP capable network proxy node, and where the UE is connectable to a controller of a first radio access type, RAT, with an active MPTCP subflow, which MPTCP capable network system further is adapted to it to decide by a controller of a second RAT that the UE is allowed access to the second RAT based on radio level and/or traffic load level information on both first and second RAT. The MPTCP capable network system is further adapted to send by the controller of the second RAT or by the UE, to the MPTCP capable network proxy node, an indication, when the controller of the second RAT has decided that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT. In addition, the MPTCP capable network system is also adapted to trigger by the MPTCP capable network proxy node an MPTCP control action to reduce control signaling in the network and/or the UE, based on the received indication.

RAT that is capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a UE connected to the MPTCP capable network proxy node, and where the UE is connectable to a controller of a second radio access type, RAT, with an active MPTCP subflow. The network proxy node comprises a processor and a memory storing a computer program comprising computer program code which when run in the processor, causes the controller of the second RAT to detect that the UE performance has decreased beyond a first threshold. Also, when the computer program code is run in the processor, it also causes the controller of the second RAT to send to the MPTCP capable network proxy node an indication that the UE performance has decreased beyond the first threshold.

According to still yet another aspect, the present disclosure provides a computer program having computer readable program code which when run in a processor of a controller of the second RAT, capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a UE connected to a MPTCP capable network proxy node, and where the UE is connectable to a controller of a second RAT with an active MPTCP subflow, causes it to detect that the UE performance has decreased beyond a first threshold. When the computer readable program code is run in the processor it also causes the controller of the second RAT to send to the MPTCP capable network proxy node an indication that the UE performance has decreased beyond the first threshold.

According to still yet another aspect, the present disclosure provides a controller of the second RAT, capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a UE connected to a MPTCP capable network proxy node, and where the UE is connectable to a controller of a second RAT with an active MPTCP subflow, which MPTCP capable network proxy node further is adapted to detect that the UE performance has decreased beyond a first threshold, and to send to the MPTCP capable network proxy node an indication that the UE performance has decreased beyond the first threshold.

According to still yet another aspect, the present disclosure provides a MPTCP capable network proxy node that is capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a UE connected to the MPTCP capable network proxy node, and where the UE is connectable to a controller of a second radio access type, RAT, with an active MPTCP subflow. The network proxy node comprises a processor and a memory storing a computer program comprising computer program code which when run in the processor, causes the MPTCP capable network proxy node to receive an indication from a controller of a second RAT. Also, when the computer program code is run in the processor, it causes the MPTCP capable network proxy node to trigger an MPTCP control action to reduce control signaling in the UE, based on the received indication.

According to still yet another aspect, the present disclosure provides a computer program having computer readable program code which when run in a processor of a MPTCP capable network proxy node, capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a UE connected to the MPTCP capable network proxy node, and where the UE is connectable to a controller of a first radio access type, RAT, with an active MPTCP subflow, causes it to receive an indication from a controller of a second RAT. Also, when the computer readable program code is run in the processor, it causes the

MPTCP capable network proxy node to trigger an MPTCP control action to reduce control signaling in the UE, based on the received indication.

According to still yet another aspect, the present disclosure provides a MPTCP capable network proxy node, capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a UE connected to the MPTCP capable network proxy node, and where the UE is connectable to a controller of a first radio access type, RAT, with an active MPTCP subflow, which MPTCP capable network proxy node further is adapted to receive an indication from a controller of a second RAT, and to trigger an MPTCP control action to reduce control signaling in the UE, based on the received indication.

According to still yet another aspect, the present disclosure provides a MPTCP capable UE capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for the UE connected to a MPTCP capable network proxy node, and where the UE is connectable to a controller of a second radio access type, RAT, with an active MPTCP subflow. The network proxy node comprises a processor and a memory storing a computer program comprising computer program code which when run in the processor, causes the MPTCP capable UE to receive an indication that a MPTCP subflow over a first RAT is setup to the MPTCP capable network proxy node. When run in the processor , it further causes the MPTCP capable UE to receive a trigger from the MPTCP capable network proxy node triggering the release of the MPTCP subflow over the second RAT; and/or release the second RAT.

According to still yet another aspect, the present disclosure provides a computer program having computer readable program code which when run in a processor of a MPTCP capable UE capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first RAT, where MPTCP session continuity is applied for a UE connected to the MPTCP capable network proxy node, and where the UE is connectable to a controller of a second radio access type, RAT, with an active MPTCP subflow, causes the MPTCP capable UE to receive an indication that a MPTCP subflow over a first RAT is setup to the MPTCP capable network proxy node. When the computer readable program code is run in the processor, it also causes the MPTCP capable UE to receive a trigger from the MPTCP capable network proxy node triggering the release of the MPTCP subflow over the second RAT; and/or release the second RAT.

According to still yet another aspect, the present disclosure provides a MPTCP capable UE capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for the UE connected to a MPTCP capable network proxy node, and where the UE is connectable to a controller of a first radio access type, RAT, with an active MPTCP subflow, which MPTCP capable UE is further adapted to receive an indication that a MPTCP subflow over a first RAT is setup to the MPTCP capable network proxy node, to receive a trigger from the MPTCP capable network proxy node triggering the release of the MPTCP subflow over the second RAT; and/or release the second RAT.

According to still yet another aspect, the present disclosure provides a MPTCP capable network system that is capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a UE connected to a MPTCP capable network proxy node, and where the UE is connectable to a controller of a second RAT, with an active MPTCP subflow. The MPTCP capable network system comprises a processor and a memory storing a computer program comprising computer program code which when run in the processor, causes the MPTCP capable network proxy node to detect by a controller of a second RAT that the UE performance has decreased to a threshold. When the computer program code is run in the processor, it also causes the MPTCP capable network system to send by the controller of the second

RAT, to the MPTCP capable network proxy node, an indication, when the controller of the second RAT has detected that the UE performance has decreased to the threshold, the MPTCP capable network proxy node to receive the indication from the controller of the second RAT. In addition, when the computer program code is run in the processor, it also causes the MPTCP capable network system to trigger by the MPTCP capable network proxy node an MPTCP control action to reduce control signaling in the network, based on the indication as received by the MPTCP capable network proxy node.

According to still yet another aspect, the present disclosure provides a computer program having computer readable program code which when run in a processor of a MPTCP capable network system that is capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a UE connected to the MPTCP capable network proxy node, and where the UE is connectable to a controller of a first RAT, with an active MPTCP subflow, causes it to detect by a controller of a second RAT that the UE performance has decreased to a threshold. When the computer readable program code is run in the processor, it further causes the MPTCP capable network system to send by the controller of the second RAT, to the MPTCP capable network proxy node, an indication, when the controller of the second RAT has detected that the UE performance has decreased to the threshold, the MPTCP capable network proxy node to receive the indication from the controller of the second RAT. In addition, when the computer readable program code is run in the processor, it also causes the MPTCP capable network system to trigger by the MPTCP capable network proxy node an MPTCP control action to reduce control signaling in the network, based on the indication as received by the MPTCP capable network proxy node. According to still yet another aspect, the present disclosure provides a MPTCP capable network system capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first RAT, where MPTCP session continuity is applied for a UE connected to a MPTCP capable network proxy node, and where the UE is connectable to a controller of a first RAT with an active MPTCP subflow, which MPTCP capable network system is further adapted to detect by a controller of a second RAT that the UE performance has decreased to a threshold. The MPTCP capable network system is also adapted to send by the controller of the second RAT, to the MPTCP capable network proxy node, an indication, when the controller of the second RAT has detected that the UE performance has decreased to the threshold, the MPTCP capable network proxy node to receive the indication from the controller of the second RAT. The MPTCP capable network system is also adapted to trigger by the MPTCP capable network proxy node an MPTCP control action to reduce control signaling in the network, based on the indication as received by the MPTCP capable network proxy node.

According to still yet another aspect, the present disclosure provides a controller of a second RAT, capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, when MPTCP session continuity is applied for a user equipment, UE, connected to a MPTCP capable network proxy node, wherein the UE is connected to a controller of a first radio access type, RAT, with an active MPTCP subflow. The controller comprises a deciding unit that is adapted to decide that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT. The controller of the second RAT also comprises a transmitting unit that is adapted to send an indication to the MPTCP capable network proxy node when the controller of the second RAT has decided that the UE is allowed to access the second RAT.

According to still yet another aspect, the present disclosure provides a MPTCP capable network proxy node capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a user equipment, UE, connected to a MPTCP capable network proxy node, wherein the UE is connected to a controller of a first radio access type, RAT, with an active MPTCP subflow. The MPTCP capable network proxy node comprises a receiving unit that is adapted to receive an indication from a controller of a second RAT or from the UE, when the controller of the second RAT has decided that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT. In addition, the MPTCP capable network proxy node also comprises a triggering unit that is adapted to trigger an MPTCP control action to reduce control signaling in the network and/or the UE, based on the received indication.

According to still yet another aspect, the present disclosure provides a MPTCP capable UE for which a first RAT has a lower priority than a second RAT. The MPTCP capable UE comprises an initiating unit that is adapted to:

- when initiating a MPTCP session between the UE and a MPTCP capable network proxy node: - initiate a first RAT subflow, if only said first RAT is available to the UE,

According to still yet another aspect, the present disclosure provides a MPTCP capable network system capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, the system comprising a MPTCP capable network proxy node, a MPTCP capable UE, and a controller of a second RAT, as herein described above.

According to still yet another aspect, the present disclosure provides a controller of a second RAT, capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, when MPTCP session continuity is applied for a user equipment, UE, connected to a MPTCP capable network proxy node, wherein the UE is connected to a controller of a second radio access type, RAT, with an active MPTCP subflow. The controller comprises a detecting unit that is adapted to detect that the UE performance has decreased beyond a first threshold. The controller of the second RAT also comprises a transmitting unit that is adapted to send to the MPTCP capable network proxy node an indication that the UE performance has decreased beyond a first.

According to still yet another aspect, the present disclosure provides a MPTCP capable network proxy node that is capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a user equipment, UE, connected to the MPTCP capable network proxy node, and the UE being connectable to a controller of a second radio access type, RAT, with an active MPTCP subflow. The MPTCP capable network proxy node comprises a receiving unit that is adapted to receive an indication from a controller of a second RAT. The MPTCP capable network proxy node also comprises a triggering unit that is adapted to trigger an MPTCP control action to reduce control signaling in the UE, based on the received indication.

According to still yet another aspect, the present disclosure provides a MPTCP capable UE capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, when MPTCP session continuity is applied for the UE connected to a MPTCP capable network proxy node, wherein the UE is connected to a controller of a second radio access type, RAT, with an active MPTCP subflow. The MPTCP capable UE comprises a receiving unit that is adapted to receive an indication that a MPTCP subflow over a first RAT is setup to the MPTCP capable network proxy node. The receiving unit may also be adapted to receive a trigger from the MPTCP capable network proxy node triggering the release of the MPTCP subflow over the second RAT, and/or that the MPTCP capable UE also comprises a releasing unit that is adapted to release the second RAT. According to still yet another aspect, the present disclosure provides a MPTCP capable network system adapted to the scenario when the UE is about to leave the coverage area of the second RAT. The MPTCP capable network system is capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, and comprises a MPTCP capable network proxy node, a MPTCP capable UE and a controller of a second RAT, all described related to the scenario when the UE is about to leave the coverage area of the second RAT.

Embodiments of the present disclosure bring the advantage of reduction of control signaling in the network and/or in the UE.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will now be described in more detail, and with reference to the accompanying drawings, in which:

- Figure 1 schematically illustrates a MPTCP usage configuration;

Figure 2 present a use case for a MPTCP proxy;

Figure 3 presents standard TCP and MPTCP protocol stacks;

Figure 4 presents multipath TCP in multi-IP scenarios;

Figure 5 illustrates MPTCP subflows in a MPTCP capable network system;

- Figure 6 presents an exemplary MPTCP capable network system;

Figures 7 and 8 present signaling diagrams of embodiments of this disclosure;

Figures 9 to 16 illustrate flowcharts of methods according to embodiments of this disclosure; and

Figures 17 to 23 schematically illustrate arrangements according to embodiments of this disclosure.

DETAILED DESCRIPTION

In the following description, different embodiments of the exemplary embodiments will be described in more detail, with reference to accompanying drawings. For the purpose of explanation and not limitation, specific details are set forth, such as particular examples and techniques in order to provide a thorough understanding.

The present disclosure provides, when MPTCP is used for "seamless session continuity at mobility", decreased control signaling, in order to minimize resource allocation and signaling load on both MPTCP level and radio access level. The present disclosure presents mechanisms on both a MPTCP proxy side as well as on a UE side. Thus, this disclosure provides a way to reduce control signaling in order to minimize resource allocation and signaling load on both MPTCP level and radio access level when MPTCP is used for "seamless session continuity at mobility". MPTCP may be defined per subscription and/or application level. In the following it is described a method and mechanism on coordination between MPTCP subflow setup/release and radio resource handling of first and second radio access types, such as 3GPP and Wi-Fi RAT, for optimizing resource allocation and control signaling on both MPTCP level and radio access level.

It has been observed that when a UE is about to enter or leave a second RAT coverage area, at some instances, a significant amount of control signaling is present.

Firstly, entering a second RAT coverage area is discussed, after which the closely related leaving the second RAT coverage area will be discussed.

Now, it has been observed the following when a UE is about to enter a second RAT cell. When a UE moves from a first RAT coverage to both first and second RAT coverage, and when the UE crosses a second RAT cell edge entering said cell, applying "second RAT when coverage", the UE would connect to the second RAT directly, after which a MPTCP subflow is established over the second RAT.

Due to the fact that no comparison is performed between the second RAT and the first RAT, the UE performance can be degraded if the radio level and/or traffic load level of the second RAT is worse than the radio level and/or traffic load level of the first RAT.

Moreover, when the UE enters into second RAT coverage and remains there, the UE in the first RAT will enter "idle mode" after a time period due to lack of data exchange on the first RAT subflow. When the MPTCP session then is terminated, the UE in first RAT will enter connected state again due to MPTCP control signaling for subflow termination as the UE needs to terminate the subflow in the first RAT, causing control signaling of the UE.

Figure 7 illustrates scenarios in a MPTCP capable system in the form of a signaling diagram when a UE is entering a second RAT, and by which control signaling is considerably reduced.

Within the signaling diagram signaling is communicated between a MPTCP UE 702, a controller of a first RAT 704, a controller of a second RAT 706, and a MPTCP capable network proxy node 708, which will be denoted MPTCP proxy down below.

In 710, the UE 702 communicates via the controller of the first RAT 704, and attaches to the first RAT in an area with good coverage on the first RAT. In 712, the MPTCP capable UE sets up a MPTCP subflow on the first RAT, via the controller of the first RAT 704. The UE then enters connected state in the first RAT.

In 714, when the UE approaches a cell edge of a second RAT cell, the UE attempts to connect to the second RAT. The second RAT controller will initially reject the second RAT, for which reason the UE will remain in the first RAT with good throughput as a result, provided the coverage of the first RAT remains sufficiently good. Two different scenarios will now be described in relation to Figure 7, dependent on which entity will establish a MPTCP subflow on the second RAT for the UE. However, not until the UE moves to a position in which the coverage of the second RAT is sufficiently improved, the attempt to connect to the second RAT can be accepted.

According to a first scenario, in 716A, the controller of the second RAT accepts the attempt 714 of the UE to connect to the second RAT. In 717A, the controller of the second RAT 706 then communicates an indicator to the MPTCP proxy 708. Subsequently, in 718A, it is the UE that sets up the MPTCP subflow on the second RAT.

According to a second scenario, in 716B, however, the controller of the second RAT 706 accepts the attempt 714 of the UE to connect to the second RAT. In 717B, the controller of the second RAT 706 then communicates an indicator to the MPTCP proxy 708, after which the MPTCP proxy 708, in 718B, sets up a MPTCP subflow on the second RAT, by communicating with the controller of the second RAT 706.

The traffic from the first RAT can then be moved to the second RAT, after which the MPTCP proxy will terminate the MPTCP subflow on the first RAT, in 720.

In 722, the MPTCP proxy 708 sends an indicator to the controller of the first RAT 704 to have the UE in the first RAT access to enter idle state. This step is typically triggered after a timeout of an inactivity timer. In 724, the UE can accordingly enter idle state initiated by the controller of the first RAT 704.

If the MPTCP session ends, only the second RAT subflow is terminated, as the UE in the first RAT will remain in idle state since the subflow in the first RAT already is terminated.

It has thus ben described how a UE can reduce control signaling when entering the coverage of the second RAT, from an area of both first and second RAT coverage.

As mentioned above, it has also been observed that when a UE is about to leave a second RAT coverage area, control signaling may be reduced.

Accordingly, the scenario when the UE is about to leave a RAT coverage area will now be discussed.

Prior to applying the described embodiment it was observed the following for a UE moving from both first and second RAT coverage to only first RAT coverage.

When the UE is located in a position with good coverage on both first and second RAT, and if the

UE for a long time has no data activity, the UE in the first RAT access enters idle state due to inactivity. As mentioned above, for MPTCP, the "seamless mobility at mobility" is used.

When now a MPTCP session is started, subflows on both first and second RAT subflows are initiated. This will result in that the UE in the first RAT access enters connected state from idle state, which causes control signaling. If the MPTCP session has no data transmission for a time duration, the UE in the first RAT access will enter idle mode due to the absence of user data, causing additional control signaling on first RAT, due to "second RAT when coverage".

When the UE approaches a cell edge of a second RAT cell, the UE will continue using the second RAT subflow for data, since the UE uses "second RAT when coverage".

When a UE stays in second RAT coverage area for too long a time before leaving said coverage area to enter a second RAT coverage only area, the UE in the first RAT access enters idle state due to inactivity, but is forced to enter connected state of the first RAT when leaving second RAT coverage. This will cause unnecessary first RAT control signaling.

When the UE then moves to the second RAT cell edge, as a result the UE performance may be degraded, since again no comparison is performed between the radio level and/or traffic load level of the first and second RAT.

Figure 8 illustrates scenarios in a MPTCP capable system in the form of a schematic hand-shake diagram when a UE is about to leave a second RAT, achieving a reduced control signaling.

Within the schematic signaling diagram signaling is communicated between a MPTCP UE 802, a controller of a first RAT 804, a controller of a second RAT 806, and a MPTCP capable network proxy node 808, which will be denoted MPTCP proxy down below.

It is noted that "MPTCP UE", denotes that the UE is MPTCP capable. In the following the "MPTCP UE" will be denoted "UE", only.

In 810, the UE 802 communicates via the controller of the first RAT 804, and is attached to the first RAT.

In 812, UE enters idle state in first RAT.

In 814, the UE 802 communicates with the controller of the second RAT 806, and attempts to connect to the second RAT, due to the UE profile as mentioned above, applying "second RAT when coverage". Since a subflow in second RAT only is initiated, the UE in the first RAT access remains in idle state.

In 816, the controller of the second RAT 804 thus accepts attempt from the UE to connect to the second RAT.

In 818, the UE can hence set up a MPTCP subflow on the second RAT, following the UE profile, via the controller of the second RAT 806.

When the UE approaches a cell edge of the second RAT, the controller of the second RAT 806 sends a trigger to the MPTCP proxy 808, in 820, triggering the MPTCP proxy to set up of a first RAT subflow. Accordingly, in 822, the MPTCP proxy setups a MPTCP subflow over the first RAT, via the controller of the first RAT 804.

Due to this first RAT activity, i.e. the setup of the subflow in the first RAT, the UE in the first RAT automatically enters connected state, in 824. When the UE continues to move towards the cell edge, it is determined that the second RAT has a performance issue, and a remove second RAT subflow is triggered. This also results that all MPTCP traffic is moved to the first RAT subflow.

This release of the second RAT can be performed by either the MPTCP proxy 808 or by the UE 802. Moreover, the second RAT may then be released by the UE. Alternatively, the second RAT is disassociated by the controller of the second RAT.

Thus, in 826A, the MPTCP proxy releases the MPTCP subflow on the second RAT, via the controller of second. Alternatively, the UE 802 releases the MPTCP subflow on the second RAT, in 826B.

Then, the MPTCP proxy can send an indication that the MPTCP subflow is released to the controller of the second RAT, in 827A, after which the controller of the second RAT disassociates the UE from the second RAT, in 828A. As an alternative to 827A and 828A, the UE 802 can release the second RAT, in 828B.

It is noted that although the UE will attempt entering the second RAT, after termination of the second RAT subflow, if second RAT coverage is still available, the UE is rejected from entering the second RAT, which further reduced control signaling.

However, when applying the embodiment above as described in connection with Figure 8, the control signaling is reduced in the following way.

Worded differently, firstly the UE first is located in a position with good coverage on both the first and the second RAT. As the UE in this example has no data activity for a long time, the UE in the first RAT access is in "idle state", i.e. the UE is not in connected state. For MPTCP, and throughout this disclosure "fast seamless mobility at mobility" mode is used.

Now, if an MPTCP session is started, since there is a UE MPTCP profile and if "second RAT when coverage" is used, the UE will only initiate a second RAT subflow. The UE in the first RAT access stays in idle state.

If the MPTCP session continues with data transmission for a while, the first RAT will still be in idle state as no first RAT subflow has been setup in previous step. Therefore no control signaling is needed.

When the UE starts approaching second RAT cell edge, the first RAT subflow will be initiated, already at this stage before the UE reaches the second RAT cell edge and may cause performance degradation. Initiation of first RAT subflow causes the UE in first RAT entering connected state.

If the UE continues to move to the second RAT cell edge at which the second RAT performance is degraded, it is determined that the second RAT has a performance issue. The network therefore removes the second RAT subflow on MPTCP level, resulting in that MPTCP traffic moves to the first RAT subflow, after which the second RAT subflow is terminated, the second RAT connection is terminated. Although the UE subsequent to the second RAT connection termination will try to re-enter second RAT as second RAT access is still available, the second RAT will be rejected for the UE when attempting to enter said second RAT, during a time period.

If the UE then moves outside second RAT coverage, no interruption occurs, since the dataflow is already moved to the first RAT.

Thereafter the MPTCP session may end, and all subflows can be terminated.

In the following, methods and arrangements enabling control signal reduction when a UE enters a second RAT coverage area and when the UE is about to leave the RAT coverage area, when the second RAT has a priority over the first RAT if the coverage is good for both first and second RAT.

In the following by referring to figures, it is described methods for reducing control signaling when entering and about to leave a second RAT coverage area for MPTCP capable entities. It will also be described the MPTCP entities, as well as computer programs for achieving the reduction of control signaling.

During a first part of disclosure it is focused at entering a second RAT coverage area. Accordingly, during a later second part of this disclosure, it is focused on when a UE is about to leave a coverage area for the second RAT.

Figure 9 that is relevant for the case when a UE is entering a second RAT coverage area, presents a flow chart of a method in a controller of a second radio access type (RAT) for controlling MPTCP subflows, and for controlling a UE radio access network state in a first radio access type, RAT, when

MPTCP session continuity is applied for a user equipment, UE, connected to a MPTCP capable network proxy node. The UE is connected to a controller of the first RAT, with an active MPTCP subflow. The method comprises deciding 92 that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT. The method also comprises sending 94 an indication to the MPTCP capable network proxy node when the UE is allowed to access the second RAT, enabling reduction of control signaling.

The method in the controller of the second RAT 706, may further comprise sending an indication to the MPTCP capable network proxy node to add a MPTCP subflow over the second RAT.

Figure 10 presents a flow chart of a method in a MPTCP capable network proxy node for controlling MPTCP subflows, and for controlling a UE radio access network state in a first radio access type, RAT. MPTCP session continuity is applied for a user equipment, UE, connected to the MPTCP capable network proxy node, wherein the UE is connected to a controller of the first RAT, with an active MPTCP subflow. The method comprises receiving 102 an indication from a controller of a second RAT or from the UE, when the controller of the second RAT has decided that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT. The method also comprises triggering 104 an MPTCP control action to reduce control signaling in the network and/or the UE, based on the received indication.

Receiving 102 the indication may comprise receiving an indication from the UE to add a MPTCP subflow over the second RAT, and wherein triggering the MPTCP action comprises releasing the active MPTCP subflow in the first RAT, and indicating the controller of the first RAT that the UE in the first RAT access connection can enter idle state.

Moreover, receiving 102 the indication may comprise receiving an indication from the controller of the second RAT that the UE is connected to the second RAT, and wherein the triggering 104 the MPTCP action comprises adding a MPTCP subflow in the second RAT and/or releasing the active MPTCP subflow in the first RAT once the added MPTCP subflow is established, and triggering indicating the controller of the first RAT to set the UE in the RAT access connection to idle state.

Figure 11 presents a flow chart of a method in a MPTCP capable UE for which a first RAT has a lower priority than a second RAT. The method comprises determining 1102 if a MPTCP session between the UE and a MPTCP capable network proxy node is being initiated. If the MPTCP session is being initiated in 1102, it is determined in 1104 whether only first RAT is available to the UE, i.e. whether there is good coverage for only the first RAT. If it is determined that the first RAT only is available in 1104, a MPTCP subflow is initiated over the first RAT.

If another RAT also or alternatively is available, in 1104, it is determined in 1108 whether only the second RAT is available, or not. If only the second RAT is available to the UE, an MPTCP subflow is initiated over the second RAT, in 1110. Further, if neither the first nor the second RAT is the only available RATs for the UE, it is determined whether the first and second RATs are available, in 1112. If both RATs are available to the UE, a subflow is initiated over the second RAT, in 1114.

Further, if it was determined in 1102 that a MPTCP session already existed, it is determined in 1116, whether a MPTCP session comprising a subflow over the first RAT is already initiated. If it is determined that there is no first RAT MPTCP subflow is already initiated in 1116, or if first and second RATs were not available in 1112, no operation is reached, in 1118.

However, if it was determined that a subflow over the first RAT was already initiated in 1116, a subflow over the second RAT is initiated when second RAT becomes available, i.e. when there is good coverage for the second RAT.

When the UE is connected to a controller of a first RAT with an active subflow to MPTCP capable network proxy node and session continuity is applied, the method may further comprise setting up a MPTCP subflow over a second RAT, when the UE is allowed to access the second RAT; and sending an indication to the MPTCP capable network proxy node when the UE has setup the MPTCP subflow over the second RAT.

The first RAT may comprise a 3rd Generation partnership program (3GPP) RAT and the second

RAT may comprise a wireless local area network (WLAN) RAT. Now a MPTCP capable network system will be presented, for which reason reference is made to Figure 12 presents a flow chart of a method in a MPTCP capable network system, for controlling MPTCP subflows, and for controlling a UE radio access network state in a first radio access type, RAT. As above, MPTCP session continuity is applied for a UE connected to a MPTCP capable network proxy node, wherein the UE is connected to a controller of a first RAT with an active MPTCP subflow.

In 122, the method comprises deciding by a controller of a second RAT that the UE is allowed access to the second RAT based on radio level and/or traffic load level information on both first and second RAT. The method also comprises sending 124 by the controller of the second RAT or by the UE, to the MPTCP capable network proxy node, an indication, when the controller of the second RAT has decided that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT. In addition, the method comprises triggering 126 by the MPTCP capable network proxy node an MPTCP control action to reduce control signaling in the network and/or the UE, based on the received indication.

Sending the indication in the method in the MPTCP capable system may comprise sending by the controller of the second RAT or by the UE, to a MPTCP capable network proxy node, an indication to add a MPTCP subflow over the second RAT, and wherein triggering comprises releasing the active MPTCP subflow in the first RAT, and indicating the controller of the first RAT that the UE in the RAT access connection can enter idle state.

Sending the indication in the method in the MPTCP capable system may comprise sending an indication from the controller of the second RAT that the UE is connected to the second RAT, and wherein triggering by the MPTCP capable network proxy node comprises adding a MPTCP subflow in the second RAT and, once it is established/or releasing the active MPTCP subflow in the first RAT, and if the first RAT is 3GPP, triggering the controller of the first RAT to set the UE in the RAT access connection to idle state.

Sending the indication in the method in the MPTCP capable system may comprise sending an indication from the UE that MPTCP subflow on the first RAT is released after the MPTCP subflow on the second RAT has been added, and wherein triggering comprises triggering the controller of the first RAT to set the UE in the RAT connection to idle state, if the first RAT is a 3 GPP RAT.

The method in the MPTCP capable network system, may also comprise setting up the MPTCP subflow on the second RAT by the MPTCP capable network proxy node, releasing the MPTCP subflow on the first RAT by either the MPTCP capable network proxy node or by the UE, and sending by the MPTCP capable network proxy node an indication to the controller of the first RAT to move the UE in the first RAT access to enter idle state.

The method in the MPTCP capable network system, may also comprise setting up the MPTCP subflow on the second RAT by the UE, releasing the MPTCP subflow on the first RAT by either the MPTCP network proxy node or by the UE, and sending by the MPTCP capable network proxy node an indication to the controller of the first RAT to have the UE in the first RAT to enter idle state.

It has thus been described methods in a controller of the second RAT, in a MPTCP capable network proxy node and in a MPTCP capable UE, for reducing controlling when entering into a second RAT coverage area.

As mentioned above, this disclosure also relates to the reducing of control signaling when a UE is about to leave a coverage area for the second RAT.

Henceforth, in the following methods in a controller of the second RAT, in a MPTCP capable network proxy node, and in a MPTCP capable UE, for reducing controlling when the UE is about to leave the coverage area for the second RAT.

It is noted that the method in the MPTCP capable UE as described in relation to Fig. 9 is also relevant also for when the UE is about to leave a coverage area for the second RAT. Further down, a figure illustrating a flow-chart that is specific for the case when the UE is about to leave the coverage area for the second RAT, will be presented.

Now, figure 13 being relevant for the case when the UE is about to leave a second RAT coverage area, presents a flowchart of a method in a controller of a second RAT for controlling MPTCP subflows, and for controlling a UE radio access network state in a first radio access type, RAT, when MPTCP session continuity is applied for a user equipment, UE, connected to a MPTCP capable network proxy node. The UE is connected to a controller of a second RAT, with an active MPTCP subflow. The method comprises detecting 132 that the UE performance has decreased beyond a first threshold. The method also comprises sending 134 to a MPTCP capable network proxy node an indication that the UE performance has decreased beyond the first threshold. A UE performance threshold may be for example calculated by using radio level and/or traffic load level information on both first and second RAT.

The method in the controller of the second RAT may further comprise receiving a trigger from the MPTCP capable network proxy node triggering the release of the MPTCP subflow over the second RAT.

Figure 14 presents a flow chart of a method in a MPTCP capable network proxy node for controlling MPTCP subflows, and for controlling a UE radio access network state in a first radio access type, RAT. MPTCP session continuity is applied for the UE being connected to the MPTCP capable network proxy node, wherein the UE is connected to a controller of a second RAT with an active MPTCP subflow. The method comprises receiving an indication from a controller of a second RAT. The method also comprises triggering an MPTCP control action to reduce control signaling in the UE, based on the received indication.

Receiving the indication may comprise receiving an indication that the UE performance has decreased beyond a first threshold, and wherein triggering the MPTCP control action comprises activating the UE in the first RAT, and adding of an MPTCP subflow for the UE in the first RAT. It can be mentioned that a UE performance threshold may be for example calculated by using radio level and/or traffic load level information on both first and second RAT.

Triggering the MPTCP control action may further comprise releasing the active MPTCP subflow in the second RAT.

Triggering the MPTCP control action may further comprise moving all data traffic to the first RAT, and, if the second RAT is Wi-Fi, sending to the controller of the second RAT, a trigger triggering removal of the access on the second RAT.

Figure 15 presents a flow chart of a method in a MPTCP capable UE, for controlling MPTCP subflows, and for controlling a UE radio access network state in a first radio access type, RAT. As above, MPTCP session continuity is applied for the UE connected to a MPTCP capable network proxy node, wherein the UE is connected to a controller of a second RAT with an active MPTCP subflow. The method comprises receiving an indication that a MPTCP subflow over a first RAT to the MPTCP capable network proxy node is setup. The method also comprises receiving a trigger from the MPTCP capable network proxy node triggering the release of the MPTCP subflow over the second RAT; and/or releasing the second RAT.

Figure 16 presents a flow chart of a method in a MPTCP capable network system, for controlling MPTCP subflows, and for controlling a UE radio access network state in a first radio access type, RAT. As above, MPTCP session continuity is applied for a UE connected to a MPTCP capable network proxy node, wherein the UE is connected to a controller of a second RAT with an active MPTCP subflow. The method comprises detecting by a controller of a second RAT that the UE performance has decreased to a threshold. The method further comprises sending by the controller of the second RAT, to the MPTCP capable network proxy node, an indication, when the controller of the second RAT has detected that the UE performance has decreased to the threshold, and the MPTCP capable network proxy node receiving the indication from the controller of the second RAT. In addition, the method also comprises triggering by the MPTCP capable network proxy node an MPTCP control action to reduce control signaling in the network, based on the indication as received by the MPTCP capable network proxy node.

It can be mentioned that a UE performance threshold may be for example calculated by using radio level and/or traffic load level information on both first and second RAT.

Receiving the indication may comprise receiving an indication from the controller of the second RAT that the UE performance has decreased beyond a first threshold; and wherein triggering the MPTCP control action comprises activating the UE in the first RAT, and adding of a MPTCP subflow for the UE in the first RAT.

Triggering the MPTCP control action may further comprise the MPTCP capable network proxy node releasing the active MPTCP subflow in the second RAT.

Triggering the MPTCP control action may further comprise the MPTCP capable UE releasing the active MPTCP subflow in the second RAT. Triggering the MPTCP control action may further comprise moving all data traffic to the first RAT, and, if the second RAT is Wi-Fi, sending to the controller of the second RAT, a trigger triggering removal of the access on the second RAT.

Triggering the MPTCP control action may further comprise moving all data traffic to the first RAT, and, if the second RAT is Wi-Fi, sending to the MPTCP capable UE, a trigger triggering removal of the access on the second RAT.

Having described methods both when the UE is entering a coverage area of the second RAT and when the UE is about to leave said coverage area, it will now be described the controller of the second RAT, the MPTCP capable network proxy node, herein called MPTCP proxy, and the MPTCP capable UE. The controller of the second RAT, the MPTCP proxy and the UE will typically be adapted for a scenario when the UE is first entering a coverage area for a second RAT, and when the UE then will be about to leave the coverage area. It should be clarified that "entering a coverage area for the second RAT" refers to going from a coverage area a first RAT into an area having good coverage of both the first and the second RAT, where the second RAT has priority over the first RAT in the sense that the UE will connect to the second RAT when there is coverage or both the first and the second RAT.

Similarly, when the UE is about to leave the coverage area refers to the case in which the UE is about leave an area having good coverage for both first and second RAT into an area having coverage for only the first RAT, again where the second RAT has priority over the first RAT, as mentioned above.

Now, returning to explain the arrangements for nodes in a MPTCP capable system, reference will be made to the accompanying figures.

Figure 17 depicts a general MPTCP capable entity 170, comprising a processor 172 and a memory 174. Since schematic illustrations of MPTCP capable entities comprising of a processor and memory do not visually differ, one and the same figure, namely figure 17 is used for the presentation of any entity comprising a processor and memory.

Therefore it can be considered that figure 17 presents a schematic illustration of a controller of the second RAT capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a UE connected to the MPTCP capable network proxy node, and where the UE is connectable to a controller of a first radio access type, RAT, with an active MPTCP subflow. The controller of the second RAT comprises a processor 172 and a memory 174 storing a computer program comprising computer program code which when run in the processor 172, causes the controller of the second RAT to decide that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT. Also, when the computer program code is run in the processor, it causes the controller of the second RAT to send an indication to the MPTCP capable network proxy node when the UE is allowed to access the second RAT, enabling reduction of control signaling. This disclosure also presents a computer program having computer readable program code which when run in a processor of a controller of the second RAT, capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a UE connected to the MPTCP capable network proxy node, and where the UE is connectable to a controller of a first radio access type, RAT, with an active MPTCP subflow, causes it to decide that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT. When the program code is run in the processor the program code further causes it to send an indication to the MPTCP capable network proxy node when the UE is allowed to access the second RAT, enabling reduction of control signaling.

This disclosure also presents a controller of the second RAT, capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a UE connected to the MPTCP capable network proxy node, and where the UE is connectable to a controller of a first radio access type, RAT, with an active MPTCP subflow, which MPTCP capable network proxy node further is adapted to decide that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT, and to send an indication to the MPTCP capable network proxy node when the UE is allowed to access the second RAT, enabling reduction of control signaling.

It can hence also be considered that figure 17 presents a schematic illustration of a MPTCP capable network proxy node that is capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a UE connected to the MPTCP capable network proxy node, and where the UE is connectable to a controller of a first radio access type, RAT, with an active MPTCP subflow. The network proxy node comprises a processor 172 and a memory 174 storing a computer program comprising computer program code which when run in the processor 172, causes the MPTCP capable network proxy node to receive an indication from a controller of a second RAT or from the UE, when the controller of the second RAT has decided that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT. Also, when the computer program code is run in the processor, it causes the MPTCP capable network proxy node to trigger an MPTCP control action to reduce control signaling in the network and/or the UE, based on the received indication.

This disclosure also presents a computer program having computer readable program code which when run in a processor of a MPTCP capable network proxy node, capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a UE connected to the MPTCP capable network proxy node, and where the UE is connectable to a controller of a first radio access type, RAT, with an active MPTCP subflow, causes it to receive an indication from a controller of a second RAT or from the UE, when the controller of the second RAT has decided that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT. When the program code is run in the processor the program code further causes it to trigger an MPTCP control action to reduce control signaling in the network and/or the UE, based on the received indication.

This disclosure also presents a MPTCP capable network proxy node, capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a UE connected to the MPTCP capable network proxy node, and where the UE is connectable to a controller of a first radio access type, RAT, with an active MPTCP subflow, which MPTCP capable network proxy node further is adapted to receive an indication from a controller of a second RAT or from the UE, when the controller of the second RAT has decided that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT. This MPTCP capable network proxy node is also adapted to trigger an MPTCP control action to reduce control signaling in the network and/or the UE, based on the received indication.

Figure 17 may hence also be considered to present a schematic illustration of a MPTCP capable UE for which a first RAT has a lower priority than a second RAT. The UE comprises a processor 172 and a memory 174 storing a computer program comprising computer program code which when run in the processor 172, causes the UE to:

- initiate 1106 a first RAT subflow, if only said first RAT is available to the UE,

- initiate 1110 a second RAT subflow, if only said second RAT is available to the UE; and

- initiate 1114 the second RAT, if both the first and the second RAT are available to the UE; and

- initiate 1120 a second RAT subflow when the second RAT becomes available to the UE.

This disclosure also presents a computer program having computer readable program code which when run in a processor of the MPTCP capable UE for which a first RAT has a lower priority than a second RAT, causes the UE to:

- when initiating a MPTCP session between the UE and a MPTCP capable network proxy node: - initiate 1106 a first RAT subflow, if only said first RAT is available to the UE,

- initiatel 120 a second RAT subflow when the second RAT becomes available to the UE. This disclosure also presents a MPTCP capable UE, for which a first RAT has a lower priority than a second RAT, which UE further is adapted to:

Figure 17 may hence also be considered to present a schematic illustration of a MPTCP capable network system that is capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applicable for a UE connectable to a MPTCP capable network proxy node, and where the UE is connectable to a controller of a first radio access type, RAT, with an active MPTCP subflow. The system comprises a processor 172 and a memory 174 storing a computer program comprising computer program code which when run in the processor 172, causes the MPTCP capable network system to decide 122 by a controller of a second RAT that the UE is allowed access to the second RAT based on radio level and/or traffic load level information on both first and second RAT. When the program code is run in the processor 172, it further causes the MPTCP capable network system to send 124 by the controller of the second RAT or by the UE, to the MPTCP capable network proxy node, an indication, when the controller of the second RAT has decided that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT. In addition, when the program code is run in the processor 172, it also causes the MPTCP capable network system to trigger 126 by the MPTCP capable network proxy node an MPTCP control action to reduce control signaling in the network and/or the UE, based on the received indication.

This disclosure also presents a computer program having computer readable program code which when run in a processor of a MPTCP capable network system capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applicable for a UE connectable to a MPTCP capable network proxy node, and where the UE is connectable to a controller of a first RAT, with an active MPTCP subflow, causes it to decide 122 by a controller of a second RAT that the UE is allowed access to the second RAT based on radio level and/or traffic load level information on both first and second RAT. When the program code is run in the processor, it further causes the MPTCP capable network system to send 124 by the controller of the second RAT or by the UE, to the MPTCP capable network proxy node, an indication, when the controller of the second RAT has decided that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT. In addition, when the program code is run in the processor, it also causes the MPTCP capable network system to trigger 126 by the MPTCP capable network proxy node an MPTCP control action to reduce control signaling in the network and/or the UE, based on the received indication.

This disclosure also presents a MPTCP capable network system, capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applicable for a UE connectable to a MPTCP capable network proxy node, and where the UE is connectable to a controller of a first radio access type, RAT, with an active MPTCP subflow, which MPTCP capable network system further is adapted to it to decide 122 by a controller of a second RAT that the UE is allowed access to the second RAT based on radio level and/or traffic load level information on both first and second RAT. The MPTCP capable network system is further adapted to send 124 by the controller of the second RAT or by the UE, to the MPTCP capable network proxy node, an indication, when the controller of the second RAT has decided that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT. In addition, the MPTCP capable network system is also adapted to trigger 126 by the MPTCP capable network proxy node an MPTCP control action to reduce control signaling in the network and/or the UE, based on the received indication.

As pointed out earlier, the present disclosure relates to reducing control signaling when a UE enters a coverage area of a second RAT. However, it also related to reducing control signaling when a UE is about to leave a coverage area of a second RAT.

Above, it has been presented a controller of the second RAT, a MPTCP capable network proxy node as well as a MPTCP capable network system for reducing control signaling when a UE enters a coverage area of a second RAT. Therefore, it will now be presented a controller of the second RAT, a MPTCP capable network proxy node as well as a MPTCP capable network system for reducing control signaling when a UE is about to leave a coverage area of a second RAT.

It should be clarified that an arrangement presented herein under the scenario when UE is entering a coverage area of the second RAT, may be identical with the same type of arrangement presented under the scenario when the UE is about to leave the coverage area of the second RAT.

With reference to the general figure 17, this figure may also be considered to present a schematic illustration of a controller of the second RAT that is capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a UE connected to the MPTCP capable network proxy node, and where the UE is connectable to a controller of a second radio access type, RAT, with an active MPTCP subflow. The network proxy node comprises a processor 172 and a memory 174 storing a computer program comprising computer program code which when run in the processor 172, causes the controller of the second RAT to detect that the UE performance has decreased beyond a first threshold. Also, when the computer program code is run in the processor, it also causes the controller of the second RAT to send to the MPTCP capable network proxy node an indication that the UE performance has decreased beyond the first threshold.

This disclosure also presents a computer program having computer readable program code which when run in a processor of a controller of the second RAT, capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a UE connected to a MPTCP capable network proxy node, and where the UE is connectable to a controller of a second RAT with an active MPTCP subflow, causes it to detect that the UE performance has decreased beyond a first threshold. When the computer readable program code is run in the processor it also causes the controller of the second RAT to send to the MPTCP capable network proxy node an indication that the UE performance has decreased beyond the first threshold.

This disclosure also presents a controller of the second RAT, capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where

MPTCP session continuity is applied for a UE connected to a MPTCP capable network proxy node, and where the UE is connectable to a controller of a second RAT with an active MPTCP subflow, which MPTCP capable network proxy node further is adapted to detect that the UE performance has decreased beyond a first threshold, and to send to the MPTCP capable network proxy node an indication that the UE performance has decreased beyond the first threshold.

Figure 17 also presents a schematic illustration of a MPTCP capable network proxy node that is capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a UE connected to the MPTCP capable network proxy node, and where the UE is connectable to a controller of a second radio access type, RAT, with an active MPTCP subflow. The network proxy node comprises a processor 172 and a memory 174 storing a computer program comprising computer program code which when run in the processor 172, causes the MPTCP capable network proxy node to receive an indication from a controller of a second RAT. Also, when the computer program code is run in the processor, it causes the MPTCP capable network proxy node to trigger an MPTCP control action to reduce control signaling in the UE, based on the received indication.

This disclosure also presents a computer program having computer readable program code which when run in a processor of a MPTCP capable network proxy node, capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a UE connected to the MPTCP capable network proxy node, and where the UE is connectable to a controller of a first radio access type, RAT, with an active MPTCP subflow, causes it to receive an indication from a controller of a second RAT. Also, when the computer readable program code is run in the processor, it causes the MPTCP capable network proxy node to trigger an MPTCP control action to reduce control signaling in the UE, based on the received indication.

This disclosure also presents a MPTCP capable network proxy node, capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a UE connected to the MPTCP capable network proxy node, and where the UE is connectable to a controller of a first radio access type, RAT, with an active MPTCP subflow, which MPTCP capable network proxy node further is adapted to receive an indication from a controller of a second RAT, and to trigger an MPTCP control action to reduce control signaling in the UE, based on the received indication.

Figure 17 may hence also be considered to present a schematic illustration of a MPTCP capable UE capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for the UE connected to a MPTCP capable network proxy node, and where the UE is connectable to a controller of a second radio access type, RAT, with an active MPTCP subflow. The network proxy node comprises a processor 172 and a memory 174 storing a computer program comprising computer program code which when run in the processor 172, causes the MPTCP capable UE to receive an indication that a MPTCP subflow over a first RAT is setup to the MPTCP capable network proxy node. When run in the processor 172, it further causes the MPTCP capable UE to receive a trigger from the MPTCP capable network proxy node triggering the release of the MPTCP subflow over the second RAT; and/or release the second RAT.

This disclosure also presents a computer program having computer readable program code which when run in a processor of a MPTCP capable UE capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a UE connected to the MPTCP capable network proxy node, and where the UE is connectable to a controller of a second radio access type, RAT, with an active MPTCP subflow, causes the MPTCP capable UE to receive an indication that a MPTCP subflow over a first RAT is setup to the MPTCP capable network proxy node. When the computer readable program code is run in the processor, it also causes the MPTCP capable UE to receive a trigger from the MPTCP capable network proxy node triggering the release of the MPTCP subflow over the second RAT; and/or release the second RAT.

This disclosure also presents a MPTCP capable UE capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for the UE connected to a MPTCP capable network proxy node, and where the UE is connectable to a controller of a first radio access type, RAT, with an active MPTCP subflow, which MPTCP capable UE is further adapted to receive an indication that a MPTCP subflow over a first RAT is setup to the MPTCP capable network proxy node, to receive a trigger from the MPTCP capable network proxy node triggering the release of the MPTCP subflow over the second RAT; and/or release the second RAT. Figure 17 may hence also be considered to present a schematic illustration of a MPTCP capable network system that is capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a UE connected to a MPTCP capable network proxy node, and where the UE is connectable to a controller of a second radio access type, RAT, with an active MPTCP subflow. The MPTCP capable network system comprises a processor 172 and a memory 174 storing a computer program comprising computer program code which when run in the processor 172, causes the MPTCP capable network proxy node to detect 122 by a controller of a second RAT that the UE performance has decreased to a threshold. When the computer program code is run in the processor 172, it also causes the MPTCP capable network system to send 124 by the controller of the second RAT, to the MPTCP capable network proxy node, an indication, when the controller of the second RAT has detected that the UE performance has decreased to the threshold, the MPTCP capable network proxy node to receive the indication from the controller of the second RAT. In addition, when the computer program code is run in the processor 172, it also causes the MPTCP capable network system to trigger 126 by the MPTCP capable network proxy node an MPTCP control action to reduce control signaling in the network, based on the indication as received by the MPTCP capable network proxy node.

This disclosure also presents a computer program having computer readable program code which when run in a processor of a MPTCP capable network system that is capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a UE connected to the MPTCP capable network proxy node, and where the UE is connectable to a controller of a first radio access type, RAT, with an active MPTCP subflow, causes it to detect 122 by a controller of a second RAT that the UE performance has decreased to a threshold. When the computer readable program code is run in the processor 172, it further causes the MPTCP capable network system to send 124 by the controller of the second RAT, to the MPTCP capable network proxy node, an indication, when the controller of the second RAT has detected that the UE performance has decreased to the threshold, the MPTCP capable network proxy node to receive the indication from the controller of the second RAT. In addition, when the computer readable program code is run in the processor, it also causes the MPTCP capable network system to trigger 126 by the MPTCP capable network proxy node an MPTCP control action to reduce control signaling in the network, based on the indication as received by the MPTCP capable network proxy node.

This disclosure also presents a MPTCP capable network system capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a UE connected to a MPTCP capable network proxy node, and where the UE is connectable to a controller of a first RAT with an active MPTCP subflow, which MPTCP capable network system is further adapted to detect 122 by a controller of a second RAT that the UE performance has decreased to a threshold. The MPTCP capable network system is also adapted to send 124 by the controller of the second RAT, to the MPTCP capable network proxy node, an indication, when the controller of the second RAT has detected that the UE performance has decreased to the threshold, the MPTCP capable network proxy node to receive the indication from the controller of the second RAT. The MPTCP capable network system is also adapted to trigger 126 by the MPTCP capable network proxy node an MPTCP control action to reduce control signaling in the network, based on the indication as received by the MPTCP capable network proxy node.

Also the respective arrangements relevant for the scenarios when the UE is entering or about to leave a coverage area of the second RAT, will also be presented when comprising functional units.

At first, arrangements are presented for the scenario in which the UE enters a coverage area of the second RAT.

Figure 18 presents schematically a controller of a second RAT, capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, when MPTCP session continuity is applied for a user equipment, UE, connected to a MPTCP capable network proxy node, wherein the UE is connected to a controller of a first radio access type, RAT, with an active MPTCP subflow. The controller comprises a deciding unit 182 that is adapted to decide that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT. The controller of the second RAT also comprises a transmitting unit 184 that is adapted to send an indication to the MPTCP capable network proxy node when the controller of the second RAT has decided that the UE is allowed to access the second RAT.

Figure 19 presents schematically a MPTCP capable network proxy node 190 capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a user equipment, UE, connected to a MPTCP capable network proxy node, wherein the UE is connected to a controller of a first radio access type, RAT, with an active MPTCP subflow. The MPTCP capable network proxy node comprises a receiving unit 192 that is adapted to receive an indication from a controller of a second RAT or from the UE, when the controller of the second RAT has decided that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT. In addition, the MPTCP capable network proxy node also comprises a triggering unit 194 that is adapted to trigger an MPTCP control action to reduce control signaling in the network and/or the UE, based on the received indication.

The triggering unitl94 may be considered to comprise a releasing unit being adapted to release the active MPTCP subflow in the first RAT, and to indicate the controller of the first RAT that the UE in the first RAT access connection can enter idle state.

The triggering unit 194 may be considered to also comprise an MPTCP subflow adding unit adapted to add a MPTCP subflow in the second RAT. The triggering unit 194 may be adapted to send a trigger to the controller of the first RAT to set the UE in the first RAT access connection to idle state. Figure 20 presents schematically a MPTCP capable UE 200 for which a first RAT has a lower priority than a second RAT. The MPTCP capable UE comprises an initiating unit 202that is adapted to:

- initiate a first RAT subflow, if only said first RAT is available to the UE,

Figure 21 presents schematically a MPTCP capable network system 210 capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, the system comprising a MPTCP capable network proxy node, a MPTCP capable UE, and a controller of a second RAT, as herein described above.

Now, arrangements are presented for the scenario in which the UE is about to leave the coverage area of the second RAT.

Figure 22 presents schematically a controller 220 of a second RAT, capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, when

MPTCP session continuity is applied for a user equipment, UE, connected to a MPTCP capable network proxy node, wherein the UE is connected to a controller of a second radio access type, RAT, with an active MPTCP subflow. The controller comprises a detecting unit 222 that is adapted to detect that the UE performance has decreased beyond a first threshold. The controller of the second RAT also comprises a transmitting unit 224 that is adapted to send to the MPTCP capable network proxy node an indication that the UE performance has decreased beyond a first.

Figure 19 may also be considered to present a MPTCP capable network proxy node that is capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a user equipment, UE, connected to the MPTCP capable network proxy node, and the UE being connectable to a controller of a second radio access type, RAT, with an active MPTCP subflow. The MPTCP capable network proxy node comprises a receiving unit 192 that is adapted to receive an indication from a controller of a second RAT. The MPTCP capable network proxy node also comprises a triggering unit 194 that is adapted to trigger an MPTCP control action to reduce control signaling in the UE, based on the received indication. The triggering unit 194 may be considered to comprise an activating unit that is adapted to activate the UE in the first RAT and to add a MPTCP subflow for the UE in the first RAT, if the receiving unit is adapted to receive an indication that the UE performance for the UE has decreased beyond a first RAT.

The triggering unit 194 may be considered to comprise a releasing unit that is adapted to release the active subflow in the second RAT.

The triggering unit 194 may also be considered to be adapted to move all data traffic to the first RAT, and to send a trigger to the controller of the second RAT to remove the access on the second RAT.

Figure 23 presents schematically a MPTCP capable UE 230 capable of controlling MPTCP subflows, and for controlling a UE radio access network state in a first radio access type, RAT, when MPTCP session continuity is applied for the UE connected to a MPTCP capable network proxy node, wherein the UE is connected to a controller of a second radio access type, RAT, with an active MPTCP subflow. The MPTCP capable UE comprises a receiving unit 232 that is adapted to receive an indication that a MPTCP subflow over a first RAT is setup to the MPTCP capable network proxy node. The receiving unit 232 may also be adapted to receive 152 a trigger from the MPTCP capable network proxy node triggering the release of the MPTCP subflow over the second RAT, and/or that the MPTCP capable UE also comprises a releasing unit 234 that is adapted to release 154 the second RAT.

Figure 21 may also be considered to present a MPTCP capable network system adapted to the scenario when the UE is about to leave the coverage area of the second RAT. The MPTCP capable network system 210 is capable of controlling MPTCP subflows, and of controlling a UE radio access network state in a first radio access type, RAT, and comprises a MPTCP capable network proxy node 212, a MPTCP capable UE and a controller of a second RAT, all described related to the scenario when the UE is about to leave the coverage area of the second RAT.

It may be further noted that the above described embodiments are only given as examples and should not be limiting to the present exemplary embodiments, since other solutions, uses, objectives, and functions are apparent within the scope of the embodiments as claimed in the accompanying patent claims.

ABBREVIATIONS

3GPP 3^r generation partnership program

IP Internet protocol

LLC logical link control

LTE long term evolution

MAC medium access control

MPTCP multipath TCP PDCP packet data control protocol

RFC request for comments

RAT radio access type

RLC radio link control

TCP transmission control protocol

UE user equipment

WLAN wireless local area network

Claims

A method in a multipath transmission control protocol, MPTCP, capable network proxy node (1 0, 216, 708) for controlling MPTCP subflow establishment and release, and for controlling UE radio access network state in a first radio access type, RAT, when MPTCP session continuity is applied for a user equipment, UE, connected to the MPTCP capable network proxy node, wherein the UE is connected to a controller of the first RAT, with an active MPTCP subflow, the method comprising:

- receiving (102, 717A; 717B) an indication from a controller of a second RAT or from the UE, when the controller of the second RAT has decided that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT; and

- triggering (104, 718A; 718B, 720) an MPTCP control action to reduce control signaling in the network and/or the UE, based on the received indication.

The method according to claim 1, wherein receiving the indication comprises receiving (717A;

717B) an indication from the UE to add a MPTCP subflow over the second RAT, and wherein triggering the MPTCP action comprises releasing (720) the active MPTCP subflow in the first RAT, and indicating (722) the controller of the first RAT that UE in the first RAT access can enter (724) idle state.

The method according to claim 1 or 2, wherein receiving the indication comprises receiving an indication from the controller of the second RAT that the UE is connected to the second RAT, and wherein the triggering the MPTCP action comprises adding (718A; 718B) a MPTCP subflow in the second RAT and/or releasing (720) the active MPTCP subflow in the first RAT once the added MPTCP subflow is established, and triggering indicating (722) the controller of the first RAT to set the UE in the first RAT access to idle state.

A method in a controller of a second radio access type, RAT, (706), for establishing and/or releasing a second RAT connection, and for controlling UE radio access network state in a first radio access type, RAT when MPTCP session continuity is applied for a user equipment, UE, connected to a MPTCP capable network proxy node, wherein the UE is connected to a controller of the first RAT, with an active MPTCP subflow, the method comprising:

- deciding (92, 716A; 716B) that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT; and

- sending (94, 717A; 717B) an indication to the MPTCP capable network proxy node when the UE is allowed to access the second RAT, enabling reduction of control signaling. The method in the controller of the second RAT (706), further comprising sending an indication to the MPTCP capable network proxy node to add a MPTCP subflow over the second RAT.

A method in a multipath transmission control protocol, MPTCP, capable user equipment, UE, (702) for which a first radio access type, RAT, has a lower priority than a second RAT, the method comprising:

- initiating (1106) a first RAT subflow, if only said first RAT is available to the UE,

- initiating (1110) a second RAT subflow, if only said second RAT is available to the UE; and

- initiating (1114) the second RAT, if both the first and the second RAT are available to the UE;

- when a MPTCP session comprising a first RAT subflow, is already initiated between the UE and the MPTCP capable network proxy node, initiating (1120) a second RAT subflow when the second RAT becomes available to the UE, enabling reduction of control signaling.

The method according to claim 6, when the UE (702) is connected to a controller of a first RAT with an active subflow to MPTCP capable network proxy node and session continuity is applied, further comprising setting up (718 A) a MPTCP subflow over a second RAT, when the UE is allowed to access the second RAT; and sending an indication to the MPTCP capable network proxy node when the UE has setup the MPTCP subflow over the second RAT.

The method according to claim 6 or 7, wherein the first RAT comprises a 3^rd Generation partnership program, 3GPP, RAT and the second RAT comprises a wireless local area network, WLAN, RAT.

A method in a multipath transmission control protocol, MPTCP, capable network system for controlling MPTCP subflow establishment and release, and for controlling UE radio access network state in a first radio access type, RAT when MPTCP session continuity is applied for a user equipment, UE, connected to a MPTCP capable network proxy node, wherein the UE is connected to a controller of the first RAT, with an active MPTCP subflow, the method comprising:

- deciding (122) by a controller of a second RAT that the UE is allowed access to the second RAT based on radio level and/or traffic load level information on both first and second RAT;

- sending (124) by the controller of the second RAT or by the UE, to the MPTCP capable network proxy node, an indication, when the controller of the second RAT has decided that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT; and

- triggering (126) by the MPTCP capable network proxy node an MPTCP control action to reduce control signaling in the network and/or the UE, based on the received indication.

10. The method in a MPTCP capable network system, according to claim 9, wherein sending the

indication comprises sending (717A; 717B) by the controller of the second RAT (706) or by the UE (702), to a MPTCP capable network proxy node (708), an indication to add a MPTCP subflow over the second RAT, and wherein triggering comprises releasing (720) the active MPTCP subflow in the first RAT, and indicating (722) the controller of the first RAT that the UE in the first RAT access can enter idle state.

The method in a MPTCP capable network system, according to claim 9 or 10, wherein sending the indication comprises sending (717B) an indication from the controller of the second RAT that the UE is connected to the second RAT, and wherein triggering by the MPTCP capable network proxy node comprises adding (718 A; 718B) a MPTCP subflow in the second RAT and, once it is established/or releasing (720) the active MPTCP subflow in the first RAT, and if the first RAT is 3GPP, triggering (722) the controller of the first RAT to set the UE in first RAT access to idle state.

The method in a MPTCP capable network system, according to claim 9, wherein sending the indication comprises sending (717A) an indication from the UE that MPTCP subflow on the first RAT is released after the MPTCP subflow on the second RAT has been added, and wherein triggering comprises triggering (722) the controller of the first RAT to set the UE in first RAT access connection to idle state, if the first RAT is a 3GPP RAT.

The method in a MPTCP capable network system, according to claim 9, comprising setting up (718B) the MPTCP subflow on the second RAT by the MPTCP capable network proxy node, releasing (720) the MPTCP subflow on the first RAT by either the MPTCP capable network proxy node or by the UE, and sending (722) by the MPTCP capable network proxy node an indication to the controller of the first RAT to have the UE in the first RAT to enter idle state.

14. The method in a MPTCP capable network system, according to claim 9, comprising setting up

(718 A) the MPTCP subflow on the second RAT by the UE, releasing (720) the MPTCP subflow on the first RAT by either the MPTCP network proxy node or by the UE, and sending (722) by the MPTCP capable network proxy node an indication to the controller of the first RAT to have the UE in the first RAT access to enter idle state.

A multipath transmission control protocol, MPTCP, capable network proxy node (170, 708) capable to control MPTCP subflow establishment and release, and to control UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a user equipment, UE, connected to the MPTCP capable network proxy node, and the UE being connectable to a controller of the first RAT, with an active MPTCP subflow, the network proxy node comprising:

a processor (172); and

a memory (174) storing a computer program comprising computer program code which when run in the processor (172), causes the MPTCP capable network proxy node to:

- receive (102, 717A; 717B) an indication from a controller of a second RAT or from the UE, when the controller of the second RAT has decided that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT; and

- trigger (104, 718A; 718B, 720) an MPTCP control action to reduce control signaling in the network and/or the UE, based on the received indication.

A computer program, comprising instructions which, when executed on a processor of a MPTCP, capable network proxy node, cause the processor to carry out the method according to any of claims 1 to 3.

A controller of a second radio access type, RAT, (170, 706), for establishing and/or releasing a second RAT connection, and for controlling UE radio access network state in a first radio access type, RAT when MPTCP session continuity is applied for a user equipment, UE, connected to a MPTCP capable network proxy node, wherein the UE is connected to a controller of a first radio access type, RAT, with an active MPTCP subflow, the controller comprising:

a processor (172); and

a memory (174) storing a computer program comprising computer program code which when run in the processor (172), causes the controller of the second RAT to:

- decide (92, 716A; 716B) that the UE is allowed to access the second RAT based on radio level and/or traffic load level information on the first and second RAT; and

- send (94, 717A; 717B) an indication to the MPTCP capable network proxy node when the controller of the second RAT has decided that the UE is allowed to access the second RAT, to reduce control signaling.

18. A computer program, comprising instructions which, when executed on a processor of a controller of a second RAT, cause the processor to carry out the method according to claim 4 or 5. 19. A multi path transmission control protocol, MPTCP, capable user equipment, UE, (702, 170) for which a first radio access type, RAT, has a lower priority than a second RAT, the UE comprising: a processor (172); and

a memory (174) storing a computer program comprising computer program code which when run in the processor, causes the MPTCP capable UE to:

- initiate (1106) a first RAT subflow, if only said first RAT is available to the UE,

- initiate (1110) a second RAT subflow, if only said second RAT is available to the UE; and

- initiate (1114) the second RAT, if both the first and the second RAT are available to the UE; and

- initiate (1120) a second RAT subflow when the second RAT becomes available to the UE, to reduce control signaling.

20. A computer program, comprising instructions which, when executed on a MPTCP capable UE, cause the processor to carry out the method according to any of claims 6 to 8. 21. A multipath transmission control protocol, MPTCP, capable network system adapted to control

MPTCP subflow establishment and release, and to control UE radio access network state in a first radio access type, RAT, the system comprising a MPTCP capable network proxy node (708, 190) according to claim 15 or 16, a MPTCP capable user equipment, UE, (702, 170, 200) according to claim 19 or 20, and a controller of a second radio type access, RAT (706, 180) according to claim 17 or 18.

22. A method in a multipath transmission control protocol, MPTCP, capable network proxy node (808, 190) for controlling MPTCP subflow establishment and release, and for controlling UE radio access network state in a first radio access type, RAT, when MPTCP session continuity is applied for a user equipment, UE, connected to the MPTCP capable network proxy node, wherein the UE is connected to a second radio access type, RAT, with an active MPTCP subflow, the method comprising:

- receiving (142, 820) an indication from a controller of a second RAT; and

- triggering (144, 822) an MPTCP control action to reduce control signaling in the UE, based on the received indication.

23. The method according to claim 22, wherein receiving the indication comprises receiving (820) an indication that the UE performance has decreased beyond a first threshold, and wherein triggering the MPTCP control action comprises activating (824) the UE in the first RAT, and adding (822) of an MPTCP subflow for the UE in the first RAT.

24. The method according to claim 23, wherein triggering the MPTCP control action further comprises releasing (826A; 826B) the active MPTCP subflow in the second RAT. 25. The method according to claim 24, wherein triggering the MPTCP control action further comprises moving all data traffic to the first RAT, and, if the second RAT is Wi-Fi, sending to the controller of the second RAT, a trigger triggering removal of the access on the second RAT.

26. A method in a controller of a second radio access type, RAT, (806, 220), for establishing and/or releasing a second RAT connection, and for controlling UE radio access network state in a first radio access type, RAT, when MPTCP session continuity is applied for a user equipment, UE, connected to the MPTCP capable network proxy node, wherein the UE is connected to a second radio access type, RAT, with an active MPTCP subflow, the method comprising:

detecting (132, 820) that the UE performance has decreased beyond a first threshold; and - sending (134, 820) to a MPTCP capable network proxy node an indication that the UE

performance has decreased beyond a first threshold, to reduce control signaling.

27. The method according to claim 26, further comprising receiving (826A; 826B) a trigger from the MPTCP capable network proxy node triggering the release of the MPTCP subflow over the second RAT.

28. A method in a multipath transmission control protocol, MPTCP, capable user equipment, UE, (802, 230) for establishing and releasing a MPTCP subflow, and for control UE radio access network state in a first radio access type, RAT, when MPTCP session continuity is applied for the UE, connected to a MPTCP capable network proxy node, wherein the UE is connected to a second

RAT, with an active MPTCP subflow, the method comprising: receiving (152) an indication that a MPTCP subflow over a first RAT is setup to the MPTCP capable network proxy node;

receiving (154) a trigger from the MPTCP capable network proxy node triggering the release of the MPTCP subflow over the second RAT; and/or

releasing (154) the second RAT, to reduce control signaling.

A method in a multipath transmission control protocol, MPTCP, capable network system for controlling MPTCP subflow establishment and release, and to control UE radio access network state in a first radio access type, RAT, when MPTCP session continuity is applied for a user equipment, UE, connected to a MPTCP capable network proxy node, wherein the UE is connected to a controller of a second RAT, with an active MPTCP subflow, the method comprising:

- detecting (162) by a controller of a second RAT that the UE performance has decreased to a threshold;

- sending (164, 820) by the controller of the second RAT, to the MPTCP capable network proxy node, an indication, when the controller of the second RAT has detected that the UE

performance has decreased to the threshold, the MPTCP capable network proxy node receiving the indication from the controller of the second RAT; and

- triggering (166) by the MPTCP capable network proxy node an MPTCP control action to reduce control signaling in the network, based on the indication as received by the MPTCP capable network proxy node.

The method according to claim 29, wherein receiving the indication comprises receiving (820) an indication from the controller of the second RAT that the UE performance has decreased beyond a first threshold; and wherein triggering the MPTCP control action comprises activating (824) the UE in the first RAT, and adding (822) of a MPTCP subflow for the UE in the first RAT.

The method according to claim 30, wherein triggering the MPTCP control action further comprises the MPTCP capable network proxy node releasing (826A) the active MPTCP subflow in the second RAT.

The method according to claim 30, wherein triggering the MPTCP control action further comprises the MPTCP capable UE releasing (826B) the active MPTCP subflow in the second RAT.

33. The method according to claim 31 or 32, wherein triggering the MPTCP control action further comprises moving all data traffic to the first RAT, and, if the second RAT is Wi-Fi, sending (827A) to the controller of the second RAT, a trigger triggering (828A) removal of the access on the second RAT.

The method according to claim 31 or 32, wherein triggering the MPTCP control action further comprises moving all data traffic to the first RAT, and, if the second RAT is Wi-Fi, sending (827A) to the MPTCP capable UE, a trigger triggering (828B) removal of the access on the second RAT.

A multipath transmission control protocol, MPTCP, capable network proxy node (170, 808, 190) capable to control MPTCP subflow establishment and release, and to control UE radio access network state in a first radio access type, RAT, where MPTCP session continuity is applied for a user equipment, UE, connected to the MPTCP capable network proxy node, and the UE being connectable to a controller of a second RAT, with an active MPTCP subflow, the network proxy node comprising:

a processor (172); and

- receiving (142, 820) an indication from a controller of a second RAT; and

A computer program, comprising instructions which, when executed on a processor of a multipath transmission control protocol, MPTCP, capable network proxy node, cause the processor to carry out the method according to any of claims 22 to 25.

A controller of a second radio access type, RAT (170, 806), adapted to control multipath transmission control protocol, MPTCP, subflows and to control UE radio access network state in a first radio access type, RAT, when MPTCP session continuity is applied for a user equipment, UE, connected to a MPTCP capable network proxy node, wherein the UE is connected to a controller of a second radio access type, RAT, with an active MPTCP subflow, the controller comprising:

a processor (172); and

- detecting (132, 820) that the UE performance has decreased beyond a first threshold; and

- sending (134, 820) to the MPTCP capable network proxy node an indication that the UE performance has decreased beyond the first threshold, to reduce control signaling.

38. A computer program, comprising instructions which, when executed on a processor of a controller of a second RAT, cause the processor to carry out the method according to claim 26 or 27.

39. A multipath transmission control protocol, MPTCP, capable UE (170, 802), adapted to establish and/or release a MPTCP subflow, and to control the UE radio access network state in the first

RAT, when MPTCP session continuity is applied for the UE connected to a MPTCP capable network proxy node, wherein the UE is connected to a controller of a second radio access type, RAT, with an active MPTCP subflow, the MPTCP capable UE comprising:

a processor (172); and

- a memory (174) storing a computer program comprising computer program code which when run in the processor (174), causes MPTCP capable UE to:

- receive (152) an indication that a MPTCP subflow over a first RAT is setup to the

MPTCP capable network proxy node;

- receive (154) a trigger from the MPTCP capable network proxy node triggering the release of the MPTCP subflow over the second RAT; and/or

- release (154) the second RAT, to reduce control signaling.

40. A computer program, comprising instructions which, when executed on a processor of a MPTCP capable UE, cause the processor to carry out the method according to claim 28.

41. A multipath transmission control protocol, MPTCP, capable network system adapted to control MPTCP subflow establishment and release, and to control the UE radio access network state in the first RAT, the system comprising a MPTCP capable network proxy node (808, 190) according to claim 35 or 36, a MPTCP capable user equipment, UE, (802, 230) according to claim 38 or 39, and a controller of a second radio type access, RAT, (806, 220) according to claim 37 or 38.

42. A computer program, comprising instructions which, when executed on a processor of a MPTCP capable network system, cause the processor to carry out the method according to any of claims 9 to 14, 29 to 34.