CN115553054A

CN115553054A - Packet rerouting

Info

Publication number: CN115553054A
Application number: CN202180006187.4A
Authority: CN
Inventors: 许翔; H·M·科斯基南; E·M·马尔卡玛基; M·E·莱蒂拉; O·布卢默
Original assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy
Current assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy
Priority date: 2021-04-28
Filing date: 2021-04-28
Publication date: 2022-12-30
Also published as: WO2022226838A1; EP4331316A1

Abstract

Example embodiments of the present disclosure relate to packet rerouting in a communication network. The first device receives a request from the second device to establish at least one tunnel between the first device and the third device. The first device transmits tunnel information about at least one tunnel to be established between the first device and the third device to the second device. The first device receives, from the fourth device, at least one uplink packet targeted to the first device via the third device and the at least one tunnel. This scheme may avoid uplink packet loss, e.g., during inter-donor-DU migration. Furthermore, this scheme does not violate the security policies in the transport network and the IAB-donor-DU. In other words, source filtering may be applied normally to the rerouted packets.

Description

Packet rerouting

Technical Field

Embodiments of the present disclosure relate generally to the field of telecommunications, and more particularly, to an apparatus, method, device, and computer-readable storage medium for rerouting packets in a communication network.

Background

The communication system may include one or more Integrated Access and Backhaul (IAB) nodes. The IAB donor has a wired/optical connection to the core network. It may be implemented as a gNB that terminates the wireless backhaul radio interface from one or more IAB nodes. The IAB donor may serve directly connected IAB nodes and IAB nodes linked by multiple wireless backhaul hops (hops). The IAB donor may also serve directly connected terminal devices. The IAB node may also serve connected terminal devices and other connected child IAB nodes. The IAB donor may include a Centralized Unit (CU) and one or more Distributed Units (DUs).

The IAB nodes may include DUs (IAB-DUs) and mobile terminals (IAB-MTs) that maintain connections (e.g., using dual connections) with one or more upstream nodes. The IAB node may serve one or more terminal devices that are directly connected to the IAB node.

The IAB topology in the communication system may be non-static in that migration may be performed, e.g., a handover may be performed for the IAB-MT based on signal strength, signal quality, and other factors.

Disclosure of Invention

In general, example embodiments of the present disclosure provide a scheme for rerouting packets in a communication network. Embodiments that do not fall within the scope of the claims, if any, should be construed as examples for understanding the various embodiments of the disclosure.

In a first aspect, a first device is provided. The first device comprises at least one processor; and at least one memory including computer program code. The at least one memory and the computer program code configured to, with the at least one processor, cause the first apparatus to: receiving, from a second device, a request to establish at least one tunnel between the first device and a third device; transmitting tunnel information about at least one tunnel to be established between the first device and the third device to the second device; and receiving, from the fourth device, at least one uplink packet targeted to the first device via the third device and the at least one tunnel.

In a second aspect, a second apparatus is provided. The second device comprises at least one processor; and at least one memory including computer program code. The at least one memory and the computer program code configured to, with the at least one processor, cause the second apparatus to: sending a request to the first device for establishing at least one tunnel between the first device and the third device for forwarding from the third device to the first device at least one uplink packet from the fourth device targeted to the first device; receiving tunnel information about at least one tunnel from a first device; providing tunnel information to the third device for establishment of the at least one tunnel; and providing, to the third device, identification information regarding at least one uplink packet to be forwarded from the third device to the first device through the at least one tunnel.

In a third aspect, a third apparatus is provided. The third device comprises at least one processor; and at least one memory including computer program code. The at least one memory and the computer program code configured to, with the at least one processor, cause the third apparatus to: acquiring tunnel information about at least one tunnel to be established between a third device and a first device from a second device; obtaining, from the second device, identification information regarding at least one uplink packet, the at least one uplink packet being from the fourth device and targeted for the first device, and the at least one uplink packet to be forwarded to the first device via the at least one tunnel and the third device; and if it is determined that the uplink packet received from the fourth device includes the acquired identification information, forwarding the received uplink packet to the first device via one of the at least one tunnel.

In a fourth aspect, a method is provided. The method may be performed by a first device, and the method comprises: receiving, at a first device, a request from a second device to establish at least one tunnel between the first device and a third device; transmitting tunnel information about at least one tunnel to be established between the first device and the third device to the second device; and receiving, from the fourth device, at least one uplink packet targeted to the first device via the third device and the at least one tunnel.

In a fifth aspect, a method is provided. The method may be performed by a second device, and the method comprises: sending, from the second device to the first device, a request for establishing at least one tunnel between the first device and the third device, for forwarding, from the third device to the first device, at least one uplink packet from the fourth device targeted to the first device; receiving tunnel information about at least one tunnel from a first device; providing tunnel information to the third device for establishment of the at least one tunnel; and providing, to the third device, identification information regarding at least one uplink packet to be forwarded from the third device to the first device through the at least one tunnel.

In a sixth aspect, a method is provided. The method may be performed by a third device, and the method comprises: obtaining, at a third device, tunnel information from a second device regarding at least one tunnel to be established between the third device and the first device; obtaining, from the second device, identification information regarding at least one uplink packet, the at least one uplink packet being from the fourth device and targeted for the first device, and the at least one uplink packet to be forwarded to the first device via the at least one tunnel and the third device; and if it is determined that the uplink packet received from the fourth device includes the acquired identification information, forwarding the received uplink packet to the first device via one of the at least one tunnel.

In a seventh aspect, a first apparatus is provided. The first device comprises means for: receiving, at a first apparatus, a request from a second apparatus to establish at least one tunnel between the first apparatus and a third apparatus; transmitting tunnel information regarding at least one tunnel to be established between the first device and the third device to the second device; and receiving, from the fourth apparatus, at least one uplink packet targeted to the first apparatus via the third apparatus and the at least one tunnel.

In an eighth aspect, a second apparatus is provided. The second device comprises means for: sending, from the second apparatus to the first apparatus, a request for establishing at least one tunnel between the first apparatus and the third apparatus, for forwarding, from the third apparatus to the first apparatus, at least one uplink packet from the fourth apparatus targeted for the first apparatus; receiving tunnel information regarding at least one tunnel from a first device; providing tunnel information to a third apparatus for establishment of at least one tunnel; and providing, to the third apparatus, identification information regarding at least one uplink packet to be forwarded from the third apparatus to the first apparatus through the at least one tunnel.

In a ninth aspect, a third apparatus is provided. The third device comprises means for: obtaining, at a third apparatus, tunnel information about at least one tunnel to be established between the third apparatus and a first apparatus from a second apparatus; obtaining, from the second apparatus, identification information regarding at least one uplink packet, the at least one uplink packet being from the fourth apparatus and targeted to the first apparatus, and the at least one uplink packet to be forwarded to the first apparatus via the at least one tunnel and the third apparatus; and if it is determined that the uplink packet received from the fourth apparatus includes the acquired identification information, forwarding the received uplink packet to the first apparatus via one of the at least one tunnel.

In a tenth aspect, a computer-readable medium is provided. The computer readable medium comprises program instructions which, when executed by at least one processor, cause an apparatus to perform at least a method according to the fourth aspect.

In an eleventh aspect, a computer-readable medium is provided. The computer readable medium comprises program instructions which, when executed by the at least one processor, cause the apparatus at least to perform the method according to the fifth aspect.

In a twelfth aspect, a computer-readable medium is provided. The computer readable medium comprises program instructions which, when executed by the at least one processor, cause the apparatus at least to perform the method according to the sixth aspect.

It should be understood that the summary is not intended to identify key or essential features of embodiments of the disclosure, nor is it intended to be used to limit the scope of the disclosure. Other features of the present disclosure will become readily apparent from the following description.

Drawings

Some example embodiments will now be described with reference to the accompanying drawings, in which:

FIG. 1 illustrates an example communication network in which example embodiments of the present disclosure may be implemented;

fig. 2 illustrates a signaling flow for rerouting packets in accordance with some example embodiments of the present disclosure;

fig. 3 illustrates an example IAB protocol stack for at least one tunnel in accordance with some example embodiments of the present disclosure;

fig. 4 illustrates another example IAB protocol stack for at least one tunnel, in accordance with some example embodiments of the present disclosure;

fig. 5 illustrates a signaling flow for rerouting packets according to some other example embodiments of the present disclosure;

fig. 6 illustrates a flow chart of a method implemented at a first device, according to some example embodiments of the present disclosure;

fig. 7 shows a flow diagram of a method implemented at a second device, according to some example embodiments of the present disclosure;

fig. 8 illustrates a flow chart of a method implemented at a third device, according to some example embodiments of the present disclosure;

FIG. 9 shows a simplified block diagram of an apparatus suitable for implementing an example embodiment of the present disclosure; and

fig. 10 illustrates a block diagram of an example computer-readable medium, in accordance with some example embodiments of the present disclosure.

Throughout the drawings, the same or similar reference numerals denote the same or similar elements.

Detailed Description

The principles of the present disclosure will now be described with reference to a few exemplary embodiments. It is understood that these embodiments are described for illustrative purposes only and to aid those skilled in the art in understanding and enabling the present disclosure, and do not imply any limitation as to the scope of the present disclosure. The embodiments described herein may be implemented in a variety of ways other than those described below.

In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

References in the present disclosure to "one embodiment," "an example embodiment," etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an exemplary embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term "and/or" includes any and all combinations of one or more of the listed terms.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises," "comprising," "includes," "including," "has," "having," "includes" and/or "including," when used herein, specify the presence of stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, components, and/or groups thereof.

As used in this application, the term "circuitry" may refer to one or more or all of the following:

(a) Hardware-only circuit implementations (such as implementations in analog-only and/or digital circuitry) and

(b) A combination of hardware circuitry and software, such as (as applicable):

(i) Combinations of analog and/or digital hardware circuitry and software/firmware, and

(ii) Any portion of a hardware processor with software (including a digital signal processor, software, and memory that work together to cause a device such as a mobile phone or server to perform various functions); and

(c) A hardware circuit and/or a processor, such as a microprocessor or a portion of a microprocessor, that requires software (e.g., firmware) to operate, but may not be present when software is not required to operate.

This definition of circuitry applies to all uses of this term in this application, including in any claims. As another example, the term circuitry, as used in this application, also encompasses implementations of only a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or its) accompanying software and/or firmware. The term circuitry also encompasses, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in a server, a cellular network device, or other computing or network device.

As used herein, the term "communication network" refers to a network that conforms to any suitable communication standard, such as a fifth generation (5G) system, long Term Evolution (LTE), LTE-advanced (LTE-a), wideband Code Division Multiple Access (WCDMA), high Speed Packet Access (HSPA), narrowband internet of things (NB-IoT), and so forth. Further, communication between terminal devices and network devices in the communication network may be performed according to any suitable generation communication protocol, including, but not limited to, first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, future fifth generation (5G) New Radio (NR) communication protocols, and/or any other protocol currently known or to be developed in the future. Embodiments of the present disclosure may be applied to various communication systems. Given the rapid development of communications, there are, of course, future types of communication techniques and systems with which the present disclosure may be embodied. It should not be taken as limiting the scope of the disclosure to only the above-described systems/networks.

As used herein, the term "network device" refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. Depending on the terminology and technology applied, a network device may refer to a Base Station (BS) or an Access Point (AP), e.g., a node B (nodeb or NB), an evolved node B (eNodeB or eNB), an NR NB (also known as gNB), a Remote Radio Unit (RRU), a Radio Head (RH), a Remote Radio Head (RRH), a relay, an Integrated Access Backhaul (IAB) node, an IAB-DU, and an IAB-CU, a low power node such as a femto base station, a pico base station, a non-terrestrial network (NTN), or a non-terrestrial network device such as a satellite network device, a Low Earth Orbit (LEO) satellite and a Geosynchronous Earth Orbit (GEO) satellite, an aircraft network device, and so forth.

The term "terminal device" refers to any terminal device capable of wireless communication. By way of example, and not limitation, a terminal device may also be referred to as a communication device, user Equipment (UE), subscriber Station (SS), portable subscriber station, mobile Station (MS), or Access Terminal (AT). End devices may include, but are not limited to, mobile phones, cellular phones, smart phones, voice over IP (VoIP) phones, wireless local loop phones, tablet computers, wearable end devices, personal Digital Assistants (PDAs), portable computers, desktop computers, image capture end devices such as digital cameras, gaming end devices, music storage and playback devices, in-vehicle wireless end devices, wireless endpoints, mobile stations, laptop embedded devices (LEEs), laptop installation devices (LMEs), USB dongles, smart devices, wireless client devices (CPEs), internet of things (IoT) devices, watches or other wearable devices, head Mounted Displays (HMDs), vehicles, targets, medical devices and applications (e.g., tele-surgery), industrial devices and applications (e.g., robots and/or other wireless devices operating in industrial and/or automated processing chain environments), consumer electronics, devices operating on commercial and/or industrial wireless networks, and the like. In the following description, the terms "terminal device", "communication device", "terminal", "user equipment" and "UE" may be used interchangeably.

Fig. 1 illustrates an example communication network 100 in which example embodiments of the present disclosure may be implemented. Communication network 100 may include a first device 110, a second device 120, a third device 130, a fourth device 140, a parent device 150, a parent device 160, a child device 170, a grandchild device 180, and a terminal device 190.

In the example of fig. 1, each of the first device 110 and the third device 130 is in communication with the second device 120. The fourth device 140 is connected to the first device 110 via the parent device 150. Terminal device 190 accesses communication network 100 via grandchild device 180. In other embodiments, communication network 100 may not include parent device 150 and parent device 160. In this way, the fourth device 140 may be directly connected to the first device 110.

In some embodiments, communication network 100 may be implemented as an IAB network. In such an embodiment, each of the fourth device 140, the

parent devices

150 and 160, the child device 170, and the grandchild device 180 may be implemented as an IAB node. In such embodiments, the second device 120 may be implemented as an IAB-donor-CU, and each of the first device 110 and the third device 130 may be implemented as an IAB-donor-DU. Alternatively, the first device 110 may be implemented as an IAB-donor-CU-user plane, the second device 120 may be implemented as an IAB-donor-CU-control plane, and the IAB-donor-DU serving the parent device 150 is not shown in fig. 1.

In embodiments where each of the first device 110 and the third device 130 may be implemented as an IAB-donor-DU, the first device 110 and the third device 130 may communicate with different IAB-donor-CUs. For example, a first device 110 may communicate with a second device 120 acting as a source IAB-donor-CU, and a third device 130 may communicate with a target IAB-donor-CU (not shown in fig. 1) that is different from the source IAB-donor-CU. In such an embodiment, the source IAB-donor-CU may communicate with the target IAB-donor-CU via an Xn interface.

In embodiments where communication network 100 is implemented as an IAB network, the IAB-donor-CU and IAB-donor-DU may be collectively referred to as an IAB-donor. For example, in the example of fig. 1, the second device 120, the first device 110, and the third device 130 may be collectively referred to as the IAB-donor 105. The IAB-donor 105 may be implemented as a gNB that terminates a wireless backhaul radio interface from one or more IAB nodes. The IAB-donor 105 has a wired/optical connection to the core network. It should be understood that fig. 1 illustrates, by way of example, that the IAB-donor 105 includes two IAB-donor-DUs. In other embodiments, the IAB-donor 105 may include one IAB-donor-DU or more than two IAB-donor-DUs. In the following, a CU of an IAB-donor is also referred to as donor-CU or donor central unit or IAB-donor-CU; and the DU of the IAB-donor is also called donor-DU or donor distributed unit or IAB-donor-DU.

In embodiments where communication network 100 is implemented as an IAB network, an IAB node (e.g., each of

devices

140, 150, 160, 170, and 180) may include a DU (IAB-DU) and a mobile terminal (IAB-MT) that maintains a connection (e.g., using dual connections) with one or more upstream nodes. Similar to conventional user equipment, the MT of an IAB node may use Radio Resource Control (RRC) signaling to provide its current serving gNB CU with radio link measurements of alternative upstream nodes. Migration may be performed, for example, handover for IAB-MT may be performed based on signal strength, signal quality, and other factors. Thus, an IAB topology such as that shown in fig. 1 may be non-static. As a result of the migration, device 140 may change the parent node from source parent node device 150 to target parent node device 160 after the migration. IAB topology may change over time, be added or removed when radio conditions fluctuate, and when IAB nodes move.

A CU (e.g. donor-CU) may be a logical node, which CU may comprise the following functions (e.g. the gNB function) in addition to those exclusively allocated to the DUs: such as the transfer of user data, mobility control, radio access network sharing, positioning, session management, etc. The CU can control the operation of the DU over the forward (F1) interface. A DU is a logical node that may include a subset of the above functions (e.g., the gNB functions).

The IAB-donor 105 may serve directly connected IAB nodes, e.g.,

devices

150 and 160 acting as IAB nodes, and IAB nodes linked by multiple wireless backhaul hops, e.g.,

devices

140, 170, and 180 acting as IAB nodes. The IAB-donor 105 may also serve directly connected terminal devices (not shown). IAB nodes, such as

devices

140, 150, 160, 170, and 180 acting as IAB nodes, may serve one or more terminal devices directly connected thereto. For example, as shown in FIG. 1, device 180 may serve a terminal device 190 that is directly connected to device 180.

It should be understood that the number of IAB nodes and terminal devices connected to the IAB nodes is for illustration purposes only and does not imply any limitation. The IAB network may include any suitable number of IAB nodes and terminal devices suitable for implementing example embodiments of the present disclosure. In other embodiments, first device 110 may be implemented as other network devices. For example, in the case of protecting traffic between the second device 120 and the fourth device 140 (or the child device 170, or the grandchild device 180, etc.) using an IPsec tunnel mode with a separate security gateway (SEG), the first device 110 may be implemented as the SEG.

It should be understood that the architecture of the network 100 shown in fig. 1 is described for illustrative purposes only and does not imply any limitations. Further, it should be understood that the number of devices and their connections shown in FIG. 1 are for illustration purposes only and do not imply any limitations. Network 100 may include any suitable number of devices suitable for implementing embodiments of the present disclosure. Although not shown, it is to be understood that one or more additional devices may be deployed in network 100.

Communications in communication network 100 may be implemented in accordance with any suitable communication protocol, including but not limited to first generation (1G), second generation (2G), third generation (3G), fourth generation (4G), and fifth generation (5G), etc. cellular communication protocols, wireless local area network communication protocols such as Institute of Electrical and Electronics Engineers (IEEE) 802.11, etc., and/or any other protocol currently known or developed in the future. Further, the communication may utilize any suitable wireless communication technology, including but not limited to: code Division Multiple Access (CDMA), frequency Division Multiple Access (FDMA), time Division Multiple Access (TDMA), frequency Division Duplex (FDD), time Division Duplex (TDD), multiple Input Multiple Output (MIMO), orthogonal Frequency Division Multiplexing (OFDM), discrete Fourier transform spread OFDM (DFT-s-OFDM), and/or any other technique now known or later developed.

In IAB communications, a donor-DU acts as a first hop router for its descendant IAB nodes, e.g., allocating an Internet Protocol (IP) address for the IAB node from the address space of the donor-DU, which is also referred to as the Internet Protocol (IP) address for the IAB node anchored in the donor-DU. The donor-DU may perform source IP filtering (also referred to as source IP address filtering, or filtering on IP source addresses) on IP packets received from its descendant IAB nodes, according to security policies. In particular, the donor-DU may check whether the source IP address of the received IP packet is related to the donor-DU. If the received IP packet includes a source IP address that is not associated with a donor-DU, the received IP packet will be discarded.

During IAB migration, when the target donor-DU is different from the source donor-DU, donor-DU inter-migration is performed. inter-donor-DU migration within a donor-CU occurs when a source donor-DU and a target donor-DU belong to the same donor-CU. inter-donor-CU migration occurs when the source and target donor-DUs belong to different donor-CUs or the source and target donor-DUs are connected to different donor-CUs.

In some embodiments, the fourth device 140 may perform the donor-DU inter-migration procedure, e.g., due to a handover. In such an embodiment, the fourth device 140 may be referred to as an IAB node that migrates. With this migration process, fourth device 140 may change the communication connection from first device 110 to third device 130 by migrating from parent device 150 to parent device 160. In such embodiments, first device 110 may be referred to as a source IAB-donor-DU, parent device 150 may be referred to as a source parent node of fourth device 140, third device 130 may be referred to as a target IAB-donor-DU, and parent device 160 may be referred to as a target parent node of fourth device 140.

In some embodiments, the migration may be a planned migration. For example, handover preparation is performed for the migrating IAB node. Alternatively, the migration may be an unplanned migration. For example, the migrating IAB node declares a Radio Link Failure (RLF) with the source parent cell/node and then connects with the target parent cell/node.

For UL routing, the UL route Identification (ID) and source IP address of the UL packet are associated with the source donor-DU before migration. The source IP address of the IP header in the UL packet originating from the IAB node is the IP address of the IAB, which is anchored in the source donor-DU. For example, the UL route ID of the UL packet may include the BAP address of the source donor-DU, and the source IP address of the UL packet is the IP address of the IAB node allocated from the address space of the source donor-DU. After migration, the migrating IAB node and descendant IAB nodes will use the new UL route ID and new IP address associated with the target donor-DU for the UL route. The source IP address of the IP header in the UL packet is the IP address of the IAB node, which is anchored in the target donor-DU. For example, the UL route ID of the UL packet may include the BAP address of the target donor-DU, and the source IP address of the UL packet is the IP address of the IAB node allocated from the address space of the target donor-DU. In the example of fig. 1, prior to migration, the UL route ID and source IP address of the UL packet sent by fourth device 140 (or by child device 170, or by grandchild device 180, etc.) are associated with first device 110. After migration, the fourth device 140, child device 170, grandchild device 180, etc. will use the new UL routing ID and new IP address associated with the third device 130 for new UL packets sent to the second device 120.

During migration, the migrating IAB node and its descendant IAB nodes may have one or more buffered UL packets received from their respective child IAB nodes. The UL packet includes a UL route ID and an IP address associated with the source donor-DU. After migration, if the buffered UL packets are sent to the target donor-DU, the UL packets will be dropped due to source IP filtering (also referred to as source IP address filtering, or filtering on the IP source address). This will result in UL packet loss.

Some options may be considered to avoid UL packet loss. For example, in option 1, the IAB-donor-CU may configure a target IAB-donor-DU with an IP address associated with the source donor-DU for source IP filtering in the target IAB-donor-DU. However, option 1 may not work. This option can only avoid source IP filtering in the target donor-DU; however, due to the security policy, the transport network node between the target donor-DU and the target donor-CU can still implement source IP filtering and drop UL packets. For example, an IP router between the second device 120 and the third device 130 may also perform source IP filtering, which results in UL packet loss.

For another example, in option 2, source IP filtering in the target IAB-donor-DU may be suspended or disabled. However, this option may lead to security issues as the source IP filtering introduced to ensure security is disabled. This is undesirable considering that the transport network may be managed by different operators and source IP filtering may be part of their security policies.

For another example, in option 3, rerouting is allowed only in a subset of the configured IAB-donor-DUs. Option 3 may be considered a variant of option 2, where source IP filtering is suspended or disabled in the subset. Similar security issues also exist.

According to some example embodiments of the present disclosure, a scheme is provided for rerouting packets in a communication network. In this scheme, at least one tunnel is established between the first device and the third device. If the third device determines that the uplink packet received from the fourth device is targeted for the first device (e.g., based on the identification information regarding the at least one uplink packet), the third device forwards the received uplink packet to the first device via one of the at least one tunnel. This scheme may avoid uplink packet loss, e.g., during inter-donor-DU migration. Furthermore, this scheme does not violate the security policies in the transport network and the IAB-donor-DU. In other words, source IP filtering may be applied normally to rerouted packets.

Example embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

Referring now to fig. 2, a signaling flow 200 for packet rerouting is shown, in accordance with some example embodiments of the present disclosure. For purposes of discussion, the signaling flow 200 will be described with reference to fig. 1. The signaling flow 200 may involve the first device 110, the second device 120, the third device 130, the fourth device 140, the parent device 150, and the parent device 160 in fig. 1.

The second device 120 sends 205 a request to the first device 110 for establishing at least one tunnel between the first device 110 and the third device 130. Accordingly, the first device 110 receives 210 the request from the second device 120.

The second device 120 may send the request in any suitable scenario. For example, in the case of a planned migration, the second device 120 may send the request during a handover preparation of the migrating IAB (such as the fourth device 140). Alternatively, in the case of an unplanned migration, the second device 120 may send the request during the reestablishment of the migrating IAB. Alternatively, when a target IAB-donor-DU (such as the third device 130) receives a UL Backhaul Adaptation Protocol (BAP) packet related to a source donor-DU (such as the first device 110), the second device 120 may send the request according to the request from the target donor-DU.

In some example embodiments, the request may indicate a format of at least one UL packet to be forwarded to the first device 110. For example, the request may indicate whether the UL packet to be forwarded will include a BAP header. In some other embodiments, the format of the at least one UL packet to be forwarded to the first device 110 is pre-configured or predefined, and thus the format indication is not included in the request.

In some example embodiments, additionally or alternatively, the request may indicate a number of at least one tunnel to be established when multiple tunnels are to be established.

Upon receiving the request, the first device 110 sends 215 tunnel information about at least one tunnel to be established between the first device 110 and the third device 130 to the second device 120. Accordingly, the second device 120 receives 220 the tunnel information from the first device 110.

In some example embodiments, the at least one tunnel may comprise a first tunnel. In such embodiments, the tunnel information may include at least one of an IP address of the first device 110 or an Identification (ID) of a tunnel endpoint associated with the first tunnel.

In some example embodiments, the tunnel information may additionally or alternatively include a format of at least one uplink packet to be forwarded to the first device 110 through the tunnel between the first device 110 and the third device 130. For example, in case the request for establishing the at least one tunnel does not indicate the format of the at least one uplink packet, the tunnel information may comprise the format of the at least one uplink packet acceptable to the first device 110. For example, the format may indicate whether the uplink packet to be forwarded should include a BAP header. In some embodiments, the format of the at least one UL packet to be forwarded is pre-configured or predefined, and thus the format indication is not included in the tunnel information.

With continued reference to fig. 2, upon receiving the tunnel information, the second device 120 provides 225 the tunnel information to the third device 130 for establishing at least one tunnel. In an example embodiment, the second device 120 receives the format of at least one uplink packet from the first device 110 and provides it to the third device 130. In another example embodiment, the second device 120 may determine a format of at least one uplink packet to be forwarded to the first device 110 through the tunnel between the first device 110 and the third device 130 and provide it to the first device 110 and the third device 130 in the request. Accordingly, the third device 130 obtains 230 tunnel information from the second device 120.

In some example embodiments, the second device 120 may send the tunnel information directly to the third device 130, without via another target donor-CU as mentioned in the following paragraphs.

As described above, in some example embodiments, each of the first device 110 and the third device 130 may be implemented as an IAB-donor-DU. In some embodiments, the first device 110 and the third device 130 may communicate with or connect to different IAB-donor-CUs. In such embodiments, for example, during Xn application protocol (XnAP) handover preparation for planned migration or XnAP acquisition UE context for unplanned migration, the second device 120 may first send tunnel information via the Xn interface to a target donor-CU (not shown in fig. 2) in communication with the third device 130. The target donor-CU then forwards the tunnel information to the third device 130. That is, in some embodiments, the second device 120 may provide the tunnel information to the third device 130 via another device (e.g., a target donor-CU) at 225.

In addition to the tunnel information, the second device 120 provides 235 to the third device 130 identification information relating to at least one uplink packet from the fourth device 140 that is targeted to the first device 110 and is to be forwarded to the first device 110 via the at least one tunnel and the third device 130. The identification information is associated with one or more tunnels. Similar to the tunnel information, in some example embodiments, the second device 120 may send the tunnel information directly to the third device 130. Alternatively, the second device 120 can provide the identification information to the third device 130 via a target donor-CU in communication with the third device 130. Accordingly, the third device 130 obtains 240 the identification information from the second device 120.

In some example embodiments, the identification information may include at least one identification associated with the first device 110. For example, the identification information may include at least one of a source IP address or a destination IP address. In this case, the source IP address is an IP address of the IAB node allocated from the address space of the first device 110. Alternatively, the destination IP address is the IP address of the first device 110, or the IP address of the second device 120 or the security gateway. For another example, the identification information may include at least one of a BAP address or a BAP route ID. In this case, the BAP address is the same as the BAP address of the first device 110. The BAP route ID is the UL route ID and contains the BAP address of the first device 110. As another example, the at least one uplink packet may include a flow label or Differentiated Services Code Point (DSCP) and at least one of an IP address or a BAP route ID. In this case, the flow label and/or DSCP is used to further distinguish UL packets sharing an IP address or BAP route ID associated with the first device 110, but with a different flow label and/or DSCP.

After obtaining the tunnel and the identification information, the third device 130 establishes 245 at least one tunnel with the first device 110.

In some example embodiments, the signaling flow 200 may be performed during an IAB migration procedure of the fourth device 140 (also referred to as the migrating IAB node 140). Prior to IAB migration, downlink (DL) packets (e.g., F1-U traffic) are routed to the fourth device 140 (and in some embodiments its descendant IAB nodes, e.g., the child IAB 170) via the parent device 150 and the first device 110, and Uplink (UL) packets (e.g., F1-U traffic) are routed from the fourth device 140 (and in some embodiments its descendant IAB nodes, e.g., the child IAB node 170) to the second device 120. After IAB migration, downlink (DL) packets (e.g., F1-U traffic) are routed to the fourth device 140 (and in some embodiments also its descendant IAB nodes, e.g., the child IAB node 170) via the parent device 160 and the third device 130, and Uplink (UL) packets (e.g., F1-U traffic) are routed from the fourth device 140 (and in some embodiments its descendant IAB nodes, e.g., the child IAB node 170) to the second device 120.

In an embodiment where the signaling flow 200 is performed during an IAB migration of the fourth device 140, the fourth device 140 connects 250 to the target cell. For example, the fourth device 140 may be connected to a unit of the parent device 160 under the third device 130 acting as the target donor-DU. Alternatively, the fourth device 140 may be connected to a unit of the third device 130 acting as a target donor-DU, or may be connected to a cell of an IAB node under the third device 130 acting as a target donor-DU.

After migrating to target parent device 160, fourth device 140 forwards 252 the UL packet to third device 130 via target parent device 160. Thus, the third device 130 receives 254 the UL packet from the fourth device 140. The UL packet forwarded by the fourth device 140 may originate from the fourth device 140 or from a descendant IAB node, e.g., the child device 170 shown in fig. 1, the grandchild node 180 shown in fig. 1, etc.

In some example embodiments, the UL packet may comprise a UL packet that is targeted for the first device 110 and is to be forwarded to the first device 110 via the at least one tunnel and the third device 130. For example, the UL packets may be packets buffered prior to migration. Alternatively, the UL packet may include a UL packet targeted to the third device 130.

In some example embodiments, the at least one uplink packet targeting the first device 110 may include at least one identification associated with the first device 110. For example, the at least one uplink packet may include at least one of a source IP address or a destination IP address. For another example, the at least one uplink packet may include at least one of a BAP address or a BAP route ID. As another example, the at least one uplink packet may include at least one of a flow label or a Differentiated Services Code Point (DSCP).

Upon receiving the UL packet, the third device 130 determines 260 whether the UL packet includes identification information that matches the identification information obtained from the second device 120. If the UL packet includes the identification information, the third device 130 forwards 270 the UL packet to the first device 110 via one of the at least one tunnel. In other words, if the UL packet includes one or more identifications associated with the first device 110, the third device 130 forwards the UL packet to the first device 110. UL packets that include one or more identifications associated with the first device 110 are considered buffered packets. Thus, the first device 110 receives 272 the UL packet.

On the other hand, if the UL packet does not include the identification information obtained from the second device 120, the third device 130 forwards 278 the UL packet to the second device 120. In other words, if the UL packet does not include an identification associated with the first device 110, the third device 130 forwards the UL packet to the second device 120. UL packets that do not include an identification associated with the first device 110 are also considered new packets. Thus, the second device 120 receives 280 the UL packet.

The at least one tunnel may be configured in various ways. For purposes of illustration and not limitation, some example options for configuration are provided below.

Option 1: all UL packets originating from one or more IAB nodes share one tunnel. For example, in the example of fig. 1, all UL packets originating from fourth device 140 share one tunnel and all UL packets originating from child device 170 and grandchild device 180 share another tunnel. Alternatively, all UL packets originating from fourth device 140, child device 170, and grandchild device 180 share one tunnel.

In option 1, the identification information obtained in the third device 130 may include one or more source IP addresses associated with the first device 110, e.g., one or more IP addresses assigned to the fourth device 140 (and in some embodiments, its descendant IAB nodes, e.g., the child device 170), and that IP address is anchored in the first device 110, meaning that Downlink (DL) IP packets using that IP address as the destination IP address in the IP header will be routed via the first device 110. When the fourth device 140 (and in some embodiments its descendant IAB nodes, e.g., the child device 170) sends an UL IP packet (e.g., an F1-U packet), the fourth device 140 (and in some embodiments its descendant IAB nodes, e.g., the child device 170) uses its IP address as the source IP address field in the IP header of the UL packet. The third device 130 determines an applicable UL packet to be forwarded on one of the at least one tunnel and the associated tunnel based on the source IP address field in the IP header of the received UL packet and the acquired identification information. For example, when the third device 130 determines that the IP address included in the source IP address field in the received uplink packet matches the source IP address in the acquired identification information, the third device 130 forwards the received UL packet to the first device 110 via one of the at least one tunnel.

Option 2: all UL packets destined for the first device 110 share one tunnel. In option 2, the identification information obtained in the third device 130 may include one or more IP addresses associated with the first device, e.g., one or more IP addresses of the second device 120 or the security gateway, and the IP addresses may be routed via the first device 110 (e.g., UL packets destined for the second device 120 or the security gateway are routed via the first device 110). In another example embodiment, the identification information obtained in the third device 130 may include one or more UL route IDs associated with the first device 110, e.g., one or more UL route IDs assigned to the fourth device 140 and a route ID associated with the first device 110. The UL route ID includes the BAP address of the first device 110. In yet another example, the identification information obtained in the third device 130 may include one or more BAP addresses associated with the first device 110, e.g., one or more BAP addresses of the first device 110. The third device 130 determines an applicable UL packet to be forwarded through one of the at least one tunnel and the related tunnel based on the destination IP address field or UL route ID or BAP address in the IP header in the received UL packet and the acquired identification information. For example, when the third device 130 determines that the IP address included in the destination IP address field in the received uplink packet matches the destination IP address in the acquired identification information, and/or that the UL route ID included in the BAP header of the received uplink packet matches the UL route ID in the acquired identification information, and/or that the BAP address included in the received uplink packet matches the BAP address in the acquired identification information, the third device 130 forwards the received UL packet to the first device 110 via the tunnel.

Option 3: all UL packets destined for the first device 110 and sharing one or more DSCPs share one tunnel. In option 3, the identification information obtained in the third device 130 may include one or more BAP addresses associated with the first device 110 and one or more DSCP values. The third device 130 determines an applicable UL packet to be forwarded on one of the at least one tunnel and the related tunnel based on the BAP address in the received UL packet and the acquired identification information. For example, when the third device 130 determines that the BAP address included in the received uplink packet matches the BAP address in the acquired identification information and the DSCP in the IP header of the received uplink packet matches the DSCP in the acquired identification information, the third device 130 forwards the received UL packet to the first device 110 via the tunnel.

Option 4: all UL packets destined for the first device 110 and sharing one or more flow labels share one tunnel. In option 4, the identification information obtained in the third device 130 may include one or more BAP addresses associated with the first device 110 and one or more flow label values. The third device 130 determines an applicable UL packet to be forwarded on one of the at least one tunnel and the related tunnel based on the BAP address and the flow label or DSCP in the received UL packet and the acquired identification information. For example, when the third device 130 determines that the BAP address included in the received uplink packet matches the BAP address in the acquired identification information and that the flow label in the IP header of the received uplink packet matches the flow label in the acquired identification information, the third device 130 forwards the received UL packet to the first device 110 via the tunnel.

Option 5: all UL packets using one or more specific route IDs share one tunnel. In option 5, the identification information obtained in the third device 130 may include one or more UL route IDs associated with the first device 110, e.g., one or more UL route IDs assigned to the fourth device 140 and a route ID associated with the first device 110. The third device 130 determines an applicable UL packet to be forwarded on one of the at least one tunnel and the associated tunnel based on the UL route ID in the received UL packet and the acquired identification information. For example, when the third device 130 determines that the route identification included in the received uplink packet matches the UL route ID in the acquired identification information, the third device 130 forwards the received UL packet to the first device 110 via the tunnel.

It is to be appreciated that the identification information obtained in the third device 130 may include any combination of a source IP address, a destination IP address, a UL route ID, a BAP address, a DSCP, and a flow label for each of the at least one tunnel. The applicable UL packet may be identified by any combination of source IP address, destination IP address, UL route ID, BAP address, DSCP and flow label. It should also be understood that the information obtained in the third device 130 may include identification information related to the first device 110 and/or a descendant IAB node (e.g., the child device 170, etc.), and thus the obtained identification information may be applied to UL packets originating from the descendant IAB node (e.g., the child device 170, etc.). For example, the acquired identification information may include one or more IP addresses of descendant IAB nodes (e.g., the descendant IAB 170) assigned to the fourth device 140, and the IP addresses are anchored in the first device 110. When a descendant IAB node (e.g., the descendant IAB 170) of the fourth device 140 transmits an UL IP packet (e.g., an F1-U packet), the descendant IAB node (e.g., the descendant IAB 170) of the fourth device 140 uses the IP address as the source IP address field in the IP header of the UL packet.

In some example embodiments, upon receiving 272 the UL packet from the third device 130, the first device 110 determines whether the at least one uplink packet is targeted to the first device 110 based on at least one BAP header included in the received at least one uplink packet. If the at least one uplink packet is targeted to said first device 110, the first device 110 removes the at least one BAP header from the at least one uplink packet and the at least one uplink packet without the at least one BAP header is forwarded 274 to the second device 120 or the security gateway. If the at least one uplink packet does not include a BAP header, the first device 110 forwards 274 the at least one uplink packet to the second device 120 or a security gateway. Accordingly, the second device 120 receives 276 the at least one uplink packet.

In some example embodiments, the second device 120 may indicate, e.g., via the indicated packet format, whether the third device is to hold or remove the BAP header in the uplink packet received from the fourth device 140.

In some example embodiments, the established at least one tunnel may be released after the migration is complete. For example, the second device 120 may send a first request to the first device 110 for releasing at least one tunnel and a second request to the third device 130 for releasing at least one tunnel. Upon receiving the first request, the first device 110 releases the at least one tunnel. Upon receiving the second request, the third device 130 releases the at least one tunnel.

Alternatively, the at least one tunnel may be reserved and reused for other IAB nodes. For example, when the source donor-DU allocates the IP address to a different IAB node, the IAB node may later perform the same migration. This may occur for mobile IABs for trains. Alternatively, in some embodiments, the at least one tunnel may be released based on a timer.

Fig. 3 illustrates an example IAB protocol stack 300 for at least one tunnel, in accordance with some example embodiments of the present disclosure. In the example of fig. 3, the second device 120 may be implemented as an IAB-donor-CU, each of the first device 110 and the third device 130 may be implemented as an IAB-donor-DU, and each of the fourth device 140, the parent device 160 and the child device 170 may be implemented as an IAB node. Each of the fourth device 140, the parent device 160, and the child device 170 may include an IAB-DU and an IAB-MT.

As shown, the kid device 170 supports the General Packet Radio System (GPRS) tunneling protocol user plane (GTP-U) protocol, user Datagram Protocol (UDP), and IP for communicating with the second device 120. The sub-device 170 also supports BAP, radio Link Control (RLC) protocol, medium Access Control (MAC) protocol, and physical layer (PHY) protocol for communication with the fourth device 140. The fourth device 140 supports BAP, RLC, MAC, and PHY protocols for communication with the target parent device 160. The third device 130 supports BAP, RLC, MAC, and PHY protocols for communication with the target parent device 160, and supports BAP, GTP-U, UDP, and IP protocols for communication with the first device 110. The first device 110 supports IP protocols for communication with the child device 170, supports BAP, GTP-U, UDP, and IP protocols for communication with the third device 130, and supports IP, layer 1 (L1)/layer 2 (L2) protocols, for communication with the second device 120.

A General Packet Radio System (GPRS) tunneling protocol user plane (GTP-U) tunnel is established between the first device 110 and the third device 130. In other example embodiments, other tunneling protocols, such as Generic Routing Encapsulation (GRE) protocol, IP in IP tunneling protocol (e.g., mobile IP (MIP), proxy Mobile IP (PMIP)) may also be used to establish the tunnel. As shown, the BAP layer terminates in the first device 110. In this case, the UL packet forwarded from the third device 130 to the first device 110 includes a BAP header.

Fig. 4 illustrates another example IAB protocol stack 400 for at least one tunnel, according to some example embodiments of the present disclosure. Similar to the example in fig. 3, in the example of fig. 4, the second device 120 may be implemented as an IAB-donor-CU, and each of the first device 110 and the third device 130 may be implemented as an IAB-donor-DU, and each of the fourth device 140, the parent device 160, and the child device 170 may be implemented as an IAB node.

The structure of IAB protocol stack 400 is similar to the structure of IAB protocol stack 300. For example, a GTP-U tunnel is established between the first device 110 and the third device 130. In other example embodiments, other tunneling protocols may be used to establish the tunnel. As shown, unlike the example in fig. 3, in the example of fig. 4, the BAP layer terminates in a third device 130. In this case, the UL packet forwarded from the third device 130 to the first device 110 does not include a BAP header.

Referring now to fig. 5, a signaling flow 500 for rerouting packets is shown, according to some other example embodiments of the present disclosure. For purposes of discussion, signaling flow 500 will be described with reference to fig. 1. Signaling flow 500 may involve first device 110, second device 120, third device 130, fourth device 140, parent device 150, parent device 160, child device 170, grandchild device 180, and terminal device 190 in fig. 1. In some example embodiments, the signaling flow 500 may be performed during IAB migration for the fourth device 140 (also referred to as the fourth device 140). Accordingly, signaling flow 500 will be described in connection with an IAB migration procedure. However, signaling flow 500 may be performed independently of the IAB migration process.

The fourth device 140 sends 501 a measurement report message to the parent device 150. The report is based on the measurement configuration in the fourth device 140 previously received from the second device 120.

Upon receiving 502 the measurement report MESSAGE, the parent device 150 sends 503 a UL RRC MESSAGE TRANSFER MESSAGE to the second device 120 to convey the received measurement report.

Upon receiving 504 the UL RRC MESSAGE TRANSFER MESSAGE, the second device 120 sends 505 a UE CONTEXT SETUP REQUEST MESSAGE to the parent device 160 to create a UE CONTEXT for the fourth device 140 and establish one or more bearers. These bearers may be used by the fourth device 140 for its own signaling and optionally for data traffic.

Upon receiving 506 the UE CONTEXT SETUP REQUEST message, the parent device 160 responds to the second device 120 with a UE CONTEXT SETUP RESPONSE message 507. Accordingly, the second device 120 receives 508 the UE CONTEXT SETUP RESPONSE message.

After the second device 120 decides to perform the IAB node migration procedure, e.g., after receiving the UE CONTEXT SETUP RESPONSE message, the second device 120 may initiate the procedure 509 to establish at least one tunnel between the first device 110 and the third device 130. For example, acts 205, 210, 215, 220, 225, 230, 235, 240, and 245 in fig. 2 may be performed to establish at least one tunnel between the first device 110 and the third device 130. In another example, the second device 120 may initiate a procedure to establish at least one tunnel between the first device 110 and the third device 130 as early as 508, which may be performed after 504, for example.

The second device 120 sends 510 a UE CONTEXT MODIFICATION REQUEST message, which includes the generated RRCReconfiguration (RRC configuration) message, to the parent device 150. The rrcreeconfiguration message includes a default Backhaul (BH) Radio Link Control (RLC) channel and a default BAP route ID configuration for UL F1 control plane interface (F1-C)/non-F1 traffic mapping on the target path. It may include additional BH RLC channels. The action may also include the allocation of a Transport Network Layer (TNL) address routable via the third device 130. The new TNL address may be included in the RRC reconfiguration message as a replacement for the TNL address routable via the first device 110. In case internet protocol security (IPsec) tunnel mode is used to protect F1 and non-F1 traffic, the TNL address assigned is an external IP address. If the source and target paths use the same IAB-donor-DU, TNL address replacement is not necessary. The transmission action indicator in the UE CONTEXT MODIFICATION REQUEST message specifies that the data transmission to the fourth device 140 is to be stopped.

Upon receiving 511 the UE CONTEXT MODIFICATION REQUEST message, the parent device 150 forwards 512 the received rrcreeconfiguration message to the fourth device 140. Accordingly, the fourth device 140 receives 513 the forwarded RRCReconfiguration message.

The parent device 150 responds 514 to the second device 120 with a UE CONTEXT MODIFICATION RESPONSE message. Accordingly, the second device 120 receives 515 the UECONTEXT MODIFICATION RESPONSE message.

A random access procedure 516 is performed at the fourth device 140.

The fourth device 140 responds 517 to the parent device 160 with an rrcconfigurationcomplete message 517.

Upon receiving 518 the rrcreeconfigurationcomplete MESSAGE, the parent device 160 sends 519 a UL RRC MESSAGE TRANSFER MESSAGE to the second device 120 to transmit the received rrcreeconfigurationcomplete MESSAGE. Accordingly, the second device 120 receives 520 the UL RRC MESSAGE TRANSFER MESSAGE.

The second device 120 configures 521 the BH RLC channel and BAP sublayer routing entries on the target path between the fourth device 140 and the third device 130 and configures the DL mapping on the third device 130 for the target path of the fourth device 140.

After the fourth device 140 connects with the cell of the parent device 160, e.g., after performing act 521, the third device 130 starts forwarding 270 the buffered UL packets to the first device 110 via the tunnel. The packet forwarded to the first device may be a BAP PDU (or contain a BAP header) or an IP packet. Upon receiving 272 the buffered UL packet, the first device 110 may forward 522 the buffered UL packet to the second device 120. Accordingly, the second device 120 receives 523 the buffered UL packet.

The F1-C connection is switched such that the second device 120 updates the UL BH information associated with each GTP tunnel to the fourth device 140 using the new TNL address of the fourth device 140. In other words, the redirection 524 of the F1 association of the fourth device 140 to the new TNL address is performed.

The second device 120 configures 525 a BH RLC channel and BAP sublayer routing entry on the target path between the child device 170 and the third device 130, and configures DL mapping on the third device 130 for the target path of the child device 170.

The F1-C connection is switched to update the UL BH information associated with each GTP tunnel to the child device 170 with the new TNL address of the child device 170 by the second device 120. In other words, the redirection 526 of the F1 association of the child device 170 to the new TNL address is performed.

The second device 120 configures 527 the BH RLC channel and BAP sublayer routing entries on the target path between the grandchild device 180 and the third device 130 and configures the DL map on the third device 130 for the target path of the grandchild device 180.

The F1-C connection is switched to update the UL BH information associated with each GTP tunnel to the grandchild device 180 with the new TNL address of the grandchild device 180. In other words, the redirection 528 of the F1 association of the grandchild device 180 to the new TNL address is performed.

After the migration is complete, such as after act 528, the second device 120 may initiate a tunnel release 529.

It should be understood that the signaling flow in fig. 5 is provided by way of example only and not limitation. In some embodiments, similar mechanisms for packet rerouting may be used in different procedures with different signaling flows.

Fig. 6 illustrates a flowchart of an example method 600 implemented at a first device, according to some example embodiments of the present disclosure. For purposes of discussion, the method 600 will be described with reference to fig. 1 from the perspective of the first device 110.

At block 610, the first device 110 receives a request from a second device 120 in communication with the first device 110 to establish at least one tunnel between the first device 110 and a third device 130.

In some example embodiments, the request may indicate a format of at least one UL packet to be forwarded to the first device 110. For example, the request may indicate whether the UP packet will include a BAP header.

In some example embodiments, additionally or alternatively, the request may indicate a number of at least one tunnel to establish.

At block 620, the first device 110 sends tunnel information to the second device 120 regarding at least one tunnel to be established between the first device 110 and the third device 130.

In some example embodiments, the tunnel information may additionally or alternatively include a format of at least one uplink packet to be forwarded to the first device 110. For example, in case the request for establishing the at least one tunnel does not indicate a format of the at least one uplink packet, the tunnel information may comprise the format of the at least one uplink packet.

At block 630, the first device 110 receives at least one uplink packet from the fourth device 140 via the third device 130 and the at least one tunnel targeting the first device 110. The received at least one uplink packet may be a BAP PDU (or contain a BAP header) or an IP packet.

In some example embodiments, upon receiving the UL packet from the third device 130, the first device 110 determines whether the uplink packet includes a BAP header.

In some embodiments, if the uplink packet includes a BAP header, the first device 110 determines whether the uplink packet is targeted for the first device 110 based on the BAP header. If the uplink packet is targeted to the first device 110, the first device 110 removes the BAP header from the uplink packet and forwards the uplink packet without the BAP header to the second device 120 or the security gateway.

In some embodiments, the uplink packet does not include a BAP header, and first device 110 forwards the uplink packet to second device 120 or the security gateway.

Fig. 7 illustrates a flowchart of an example method 700 implemented at a second device, according to some example embodiments of the present disclosure. For purposes of discussion, the method 700 will be described with reference to fig. 1 from the perspective of the second device 120.

At block 710, the second device 120 sends a request to the first device 110 in communication with the second device 120 for establishing at least one tunnel between the first device 110 and the third device 130 for forwarding at least one uplink packet from the fourth device 140, targeted to the first device 110, from the third device 130 to the first device 110.

The second device 120 may send the request under any suitable circumstances. For example, in the case of a planned migration, the second device 120 may send the request during a handover preparation of the migrating IAB (such as the fourth device 140). Alternatively, in the case of an unplanned migration, the second device 120 may send the request during the reestablishment of the migrating IAB. Alternatively, when a target IAB-donor-DU (such as the third device 130) receives a UL Backhaul Adaptation Protocol (BAP) packet involving a source donor-DU (such as the first device 110), the second device 120 may send the request according to the request from the target donor-DU. In some embodiments, the second device 120 may send a request for tunnel establishment in advance before detecting a need for handover or reestablishment.

In some example embodiments, the request may indicate a format of at least one UL packet targeted to the first device 110. For example, the request may indicate whether the UP packet will include a BAP header.

In some example embodiments, the request may additionally or alternatively indicate a number of at least one tunnel to establish.

At block 720, the second device 120 receives tunnel information regarding the at least one tunnel from the first device 110.

In some example embodiments, the tunnel information may additionally or alternatively include a format of at least one uplink packet to be forwarded to the first device 110. For example, in case the request for establishing the at least one tunnel does not indicate the format of the at least one uplink packet, the tunnel information may comprise the format of the at least one uplink packet.

At block 730, the second device 120 provides the tunnel information to the third device 130 for establishment of the at least one tunnel.

In some example embodiments, the second device 120 may send the tunnel information directly to the third device 130.

In some example embodiments, each of the first device 110 and the third device 130 may be implemented as an IAB-donor-DU, and the first device 110 and the third device 130 may communicate with different IAB-donor-CUs.

In such an embodiment, for example, during XnAP handover preparation for planned migration or during XnAP get UE context for unplanned migration, the second device 120 may first send the tunnel information to the target donor-CU communicating with the third device 130 via the Xn interface. The target donor-CU then forwards the tunnel information to the third device 130.

At block 740, the second device 120 provides identifying information to the third device 130 regarding at least one uplink packet to be forwarded from the third device 130 to the first device 110 through the at least one tunnel.

Similar to the tunnel information, in some example embodiments, the second device 120 may send the identification information directly to the third device 130. Alternatively, the second device 120 can provide the identification information to the third device 130 via a target donor-CU in communication with the third device 130.

Fig. 8 illustrates a flowchart of an example method 800 implemented at a third device, according to some example embodiments of the present disclosure. For purposes of discussion, the method 800 will be described with reference to fig. 1 from the perspective of the third device 130.

At block 810, the third device 130 obtains tunnel information from the second device 120 regarding at least one tunnel to be established between the third device 130 and the first device 110.

In some example embodiments, the tunnel information may additionally or alternatively include a format of at least one uplink packet to be forwarded to the first device 110.

In some example embodiments, the third device 130 may receive the tunnel information directly from the second device 120.

In some example embodiments, each of the first device 110 and the third device 130 may be implemented as an IAB-donor-DU, and the first device 110 and the third device 130 may communicate with and/or be controlled by different IAB-donor-CUs. In such an embodiment, for example, during XnAP handover preparation for planned migration or during XnAP get UE context for unplanned migration, the second device 120 may first send the tunnel information to the target donor-CU communicating with the third device 130 via the Xn interface. The target donor-CU then forwards the tunnel information to the third device 130. Thus, the third device 130 may receive the tunnel information forwarded from the target donor-CU.

At block 820, the third device 130 obtains identification information from the second device 120 regarding at least one uplink packet from the fourth device 140 and targeted to the first device 110, and the at least one uplink packet is to be forwarded to the first device 110 via the at least one tunnel and the third device 130.

Similar to the tunnel information, in some example embodiments, the third device 130 may receive the identification information directly from the second device 120. Alternatively, the second device 120 may provide the identification information to the third device 130 via a target donor-CU in communication with the third device 130. Thus, the third device 130 receives the identification information forwarded from the target donor-CU.

In some example embodiments, the identification information may include at least one identification associated with the first device 110. For example, the identification information may include at least one of a source IP address or a destination IP address. As another example, the identification information may include at least one of a BAP address or a BAP route ID. As another example, the at least one uplink packet may include at least one of a flow label or a DSCP.

Upon receiving the UL packet, the third device 130 determines whether the UL packet includes identification information that matches the identification information obtained from the second device 120 at block 830. The identification information is associated with each tunnel. Accordingly, when determining that the UL packet includes identification information that matches the identification information acquired from the second device 120, the third device 130 may determine that the UL packet is an applicable packet and may also determine a relevant tunnel (in the case where more than one tunnel is established). If the UL packet includes the identification information, the third device 130 forwards the UL packet to the first device 110 via one of the at least one tunnel at block 840. In other words, the third device 130 forwards the UL packet to the first device 110 if the UL packet includes one or more identifications associated with the first device 110.

On the other hand, if the UL packet does not include the identification information, the third device 130 may forward the UL packet to the second device 120. In other words, if the UL packet does not include an identification associated with the first device 110, the third device 130 may forward the UL packet to the second device 120.

In some example embodiments, the third device 130 may determine an applicable UL packet to forward to the first device 110 based on whether the IP address included in the source IP address field in the received uplink packet matches the source IP address in the obtained identification information. In such an embodiment, if the IP address included in the source IP address field in the received uplink packet matches the source IP address in the acquired identification information, the received uplink packet is determined to be an applicable UL packet to be forwarded to the first device 110.

In some example embodiments, the third device 130 may alternatively or additionally determine an applicable UL packet to forward to the first device 110 based on whether the IP address included in the destination IP address field in the received uplink packet matches the destination IP address in the obtained identification information.

In some example embodiments, the third device 130 may alternatively or additionally determine an applicable UL packet to forward to the first device 110 based on whether the route identification included in the received uplink packet matches the UL route identification in the obtained identification information.

In some example embodiments, the third device 130 may alternatively or additionally determine an applicable UL packet to forward to the first device 110 based on whether the BAP address included in the received uplink packet matches the BAP address in the retrieved identification information.

In some example embodiments, the third device 130 may alternatively or additionally determine an applicable UL packet to forward to the first device 110 based on whether the flow label in the IP header of the received uplink packet matches the flow label in the acquired identification information.

In some example embodiments, the third device 130 may alternatively or additionally determine an applicable UL packet to forward to the first device 110 based on whether the differentiated services code point value in the IP header of the received uplink packet matches the differentiated services code point in the obtained identification information.

The above-described

methods

600, 700, and 800 may avoid uplink packet loss, e.g., during inter-donor-DU migration. Furthermore, the method 800 may not violate security policies in the transport network and the IAB-donor-DU. In other words, source filtering may be applied normally to rerouted packets and IAB-donor-DUs in the transport network.

In some embodiments, the first device may be a source donor-DU of an IAB node, the second device may be a donor-CU, the third device may be a target donor-DU of the IAB node, and the fourth device may be the IAB node.

In some example embodiments, a first apparatus (e.g., first device 110) capable of performing any of method 600 may include means for performing the respective operations of method 600. The component may be implemented in any suitable form. For example, the components may be implemented in a circuit or a software module. The first apparatus may be implemented as or comprised in the first device 110. In some example embodiments, the component may include a processor and a memory.

In some example embodiments, the first apparatus comprises means for: receiving, at the first device, a request from a second device in communication with the first device to establish at least one tunnel between the first device and a third device; transmitting tunnel information regarding the at least one tunnel to be established between the first device and the third device to the second device; and receiving, from a fourth apparatus, at least one uplink packet targeted to the first apparatus via the third apparatus and the at least one tunnel.

In some example embodiments, the at least one tunnel comprises a first tunnel, and the tunnel information comprises, for the first tunnel, at least one of: an internet protocol address of the first device, an identification of a tunnel endpoint associated with the first tunnel, or a format of the at least one uplink packet.

In some example embodiments, the at least one uplink packet targeted for the first device includes at least one of the following identifications associated with the first apparatus 110: a source IP address, a destination IP address, a BAP routing identifier, a flow label, or a differentiated services code point.

In some example embodiments, the request indicates at least one of: a format of the at least one uplink packet, a number of the at least one tunnel to be established.

In some example embodiments, the first apparatus further comprises means for: determining whether the at least one uplink packet includes at least one backhaul adaptation protocol, BAP, header; and if it is determined that the at least one uplink packet includes the at least one BAP header, determining whether the at least one uplink packet is targeted to the first device based on the at least one BAP header, if it is determined that the at least one uplink packet is targeted to the first apparatus 110, removing the at least one BAP header from the at least one uplink packet, forwarding the at least one uplink packet without the at least one BAP header to the second apparatus or a secure gateway; and forwarding the at least one uplink packet to the second apparatus or the security gateway if it is determined that the at least one uplink packet does not include the BAP header.

In some example embodiments, a second apparatus (e.g., second device 120) capable of performing any of method 700 may include means for performing the respective operations of method 700. The component may be implemented in any suitable form. For example, the components may be implemented in circuits or software modules. The second apparatus may be implemented as the second device 120 or included in the second device 120. In some example embodiments, the apparatus may include a processor and a memory.

In some example embodiments, the second means comprises means for: sending, from a second apparatus to a first apparatus in communication with the second apparatus, a request for establishing at least one tunnel between the first apparatus and a third apparatus for forwarding, from the third apparatus to the first apparatus, at least one uplink packet from a fourth apparatus targeted to the first apparatus; receiving tunnel information regarding at least one tunnel from a first device; providing tunnel information to the third device for establishment of at least one tunnel; and providing, to the third apparatus, identification information regarding at least one uplink packet to be forwarded from the third apparatus to the first apparatus through the at least one tunnel.

In some embodiments, the various examples of at least one tunnel, request, tunnel information, and identification information described above with reference to methods 600-800 and the first apparatus are also applicable here.

In some example embodiments, a third apparatus (e.g., third device 130) capable of performing any of method 800 may include means for performing the respective operations of method 800. The component may be implemented in any suitable form. For example, the components may be implemented in circuits or software modules. The third means may be embodied as or comprised in the third device 130. In some example embodiments, the component may include a processor and a memory.

In some example embodiments, the third apparatus comprises means for: obtaining, at a third apparatus, tunnel information regarding at least one tunnel to be established between the third apparatus and a first apparatus from a second apparatus; obtaining, from the second apparatus, identification information regarding at least one uplink packet, the at least one uplink packet being from the fourth apparatus and targeting the first apparatus and to be forwarded to the first apparatus and the third apparatus via at least one tunnel; and if it is determined that the uplink packet received from the fourth apparatus includes the acquired identification information, forwarding the received uplink packet to the first apparatus via one of the at least one tunnel.

In some embodiments, various examples of at least one tunnel, tunnel information, and identification information described above with reference to methods 600-800, the first device, and the second device are also applicable herein.

In some example embodiments, the above determination is based on at least one of: matching the IP address included in the source IP address field of the received uplink packet with the source IP address in the acquired identification information; matching the IP address included in the destination IP address field of the received uplink packet with the destination IP address in the acquired identification information; the route identifier included in the received uplink packet is matched with the BAP route identifier in the acquired identification information; matching the BAP address included in the received uplink packet with the BAP address in the acquired identification information; matching the flow label in the IP header of the received uplink packet with the flow label in the acquired identification information; or the differentiated services code point value in the IP header of the received uplink packet matches the differentiated services code point in the obtained identification information.

Fig. 9 is a simplified block diagram of a device 900 suitable for implementing an example embodiment of the present disclosure. The device 900 may be provided to implement a communication device, such as the first device 110, the second device 120, or the third device 130 shown in fig. 1. As shown, the device 900 includes one or more processors 910, one or more memories 920 coupled to the processors 910, and one or more communication modules 940 coupled to the processors 910.

The communication module 940 is used for bidirectional communication. The communication module 940 has one or more communication interfaces to facilitate communication with one or more other modules or devices. The communication interface may represent any interface required to communicate with other network elements. In some example embodiments, the communication module 940 may include at least one antenna.

The processor 910 may be of any type suitable for a local technology network and may include one or more of the following: by way of non-limiting example, general purpose computers, special purpose computers, microprocessors, digital Signal Processors (DSPs) and processors based on a multi-core processor architecture. Device 900 may have multiple processors, such as application specific integrated circuit chips that are time dependent from a clock that synchronizes the main processor.

The memory 920 may include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memory include, but are not limited to, read-only memory (ROM) 924, electrically programmable read-only memory (EPROM), flash memory, hard disk, compact Disk (CD), digital Video Disk (DVD), an optical disk, a laser disk, and other magnetic and/or optical storage devices. Examples of volatile memory include, but are not limited to, random Access Memory (RAM) 922 and other volatile memory that does not persist for the duration of the power loss.

Computer programs 930 include computer-executable instructions that are executable by the associated processor 910. The program 930 may be stored in a memory such as the ROM 924. Processor 910 may perform any suitable actions and processes by loading program 930 into RAM 922.

Example embodiments of the present disclosure may be implemented by way of program 930, such that device 900 may perform any of the processes of the present disclosure as discussed with reference to fig. 2-8. Example embodiments of the present disclosure may also be implemented by hardware or a combination of software and hardware.

In some example embodiments, program 930 may be tangibly embodied in a computer-readable medium, which may be included in device 900 (e.g., in memory 920) or other storage device accessible by device 900. Device 900 may load program 930 from the computer-readable medium into RAM 922 for execution. The computer readable medium may include any type of tangible, non-volatile memory, such as ROM, EPROM, flash memory, a hard disk, a CD, a DVD, etc. Fig. 10 shows an example of a computer readable medium 1000 that may be in the form of a CD, DVD, or other optical storage disc. The computer readable medium has stored thereon a program 930.

In general, the various embodiments of the disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While aspects of embodiments of the disclosure have been illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that the blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product comprises computer executable instructions, such as instructions comprised in program modules executed in a device on a target physical or virtual processor, to perform any of the methods described above with reference to figures 2 to 8. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or separated between program modules as desired in various embodiments. Machine-executable instructions of program modules may be executed within local or distributed devices. In a distributed fashion, program modules may be located in both local and remote memory storage media.

Program code for performing the methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowchart and/or block diagram to be performed. The program code may execute entirely on the machine, partly on the machine, as a stand-alone software package, partly on the machine, partly on a remote machine or entirely on the remote machine or server.

In the context of the present disclosure, computer program code or related data may be carried by any suitable carrier for enabling a device, apparatus or processor to perform various procedures and operations as described above. Examples of carrier waves include signals, computer readable media, and the like.

The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of a computer-readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

It should be appreciated that although some embodiments may be implemented by/at an IAB node, the solution including the methods and apparatus presented in this disclosure may also be applied in other communication systems where similar technical problems exist. Further, while operations are described in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In some cases, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are included in the above discussion, these should not be construed as limitations on the scope of the disclosure, but rather as descriptions of features specific to particular embodiments. Certain features that are described in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination.

Although the disclosure has been described in language specific to structural features and/or methodological acts, it is to be understood that the disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A first device, comprising:

at least one processor; and

at least one memory including computer program code;

wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the first apparatus to:

receiving, from a second device, a request to establish at least one tunnel between the first device and a third device;

transmitting tunnel information about the at least one tunnel to be established between the first device and the third device to the second device; and

receiving, from a fourth device via the third device and the at least one tunnel, at least one uplink packet targeted to the first device.

2. The first device of claim 1, wherein the at least one tunnel comprises a first tunnel, and the tunnel information comprises, for the first tunnel, at least one of:

the internet protocol address of the first device,

identification of a tunnel endpoint associated with the first tunnel, or

A format of the at least one uplink packet.

3. The first device of claim 1, wherein the at least one uplink packet targeting the first device comprises at least one of the following associated with the first device:

the source internet protocol IP address of the source,

the destination IP address is set to a value that is,

the back-haul adaptation protocol (BAP) address,

the identification of the BAP route is carried out,

flow labels, or

Differentiated services code points.

4. The first device of claim 1, wherein the request indicates at least one of:

a format of the at least one uplink packet, or

A number of the at least one tunnel to establish.

5. The first apparatus of claim 1, wherein the at least one memory and the computer program code are configured to, with the at least one processor, further cause the first apparatus to perform at least one of:

forwarding the received at least one uplink packet to a second device or a security gateway; or

If it is determined that the at least one uplink packet is targeted to the first device based on at least one backhaul adaptation protocol, BAP, header included in the received at least one uplink packet:

removing the at least one BAP header from the at least one uplink packet, an

Forwarding the at least one uplink packet without the at least one BAP header to the second device or a security gateway.

6. A second device, comprising:

at least one processor; and

at least one memory including computer program code;

wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the second apparatus to:

sending a request to a first device for establishing at least one tunnel between the first device and a third device for forwarding at least one uplink packet from a fourth device to the first device, the at least one uplink packet being targeted to the first device;

receiving tunnel information about the at least one tunnel from the first device;

providing the tunnel information to the third device for establishment of the at least one tunnel; and

providing, to the third device, identification information regarding at least one uplink packet to be forwarded from the third device to the first device through the at least one tunnel.

7. The second device of claim 6, wherein the at least one tunnel comprises a first tunnel and the tunnel information comprises, for the first tunnel, at least one of:

the internet protocol address of the first device,

identification of a tunnel endpoint associated with the first tunnel, or

A format of the at least one uplink packet.

8. The second device of claim 6, wherein the identification information comprises at least one of the following identifications associated with the first device:

the source Internet Protocol (IP) address of the source,

the destination IP address is set to a value that is,

the back-transmission adaptation protocol (BAP) address,

the identification of the BAP route is carried out,

flow labels, or

Differentiated services code points.

9. The second device of claim 6, wherein the request indicates at least one of:

a format of the at least one uplink packet, or

A number of the at least one tunnel.

10. A third apparatus, comprising:

at least one processor; and

at least one memory including computer program code;

wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the third apparatus to:

acquiring tunnel information on at least one tunnel to be established between the third device and the first device from the second device;

obtaining, from the second device, identification information regarding at least one uplink packet that is from a fourth device and that is targeted for the first device and that is to be forwarded to the first device via the at least one tunnel and the third device; and

forwarding the received uplink packet to the first device via one of the at least one tunnel if it is determined that the uplink packet received from the fourth device includes the acquired identification information.

11. The third device of claim 10, wherein the at least one tunnel comprises a first tunnel and the tunnel information comprises at least one of the following for the first tunnel:

the internet protocol address of the first device is,

identification of a tunnel endpoint associated with the first tunnel, or

A format of the at least one uplink packet.

12. The third device of claim 10, wherein the identification information comprises at least one of the following identifications associated with the first device:

the source Internet Protocol (IP) address of the source,

the destination IP address is set to a value that is,

the back-transmission adaptation protocol (BAP) address,

the identification of the BAP route is identified,

flow labels, or

Differentiated services code points.

13. The third device of claim 10, wherein the determination is based on at least one of:

the internet protocol IP address included in the source IP address field of the received uplink packet is matched with the source IP address in the acquired identification information;

the IP address included in the destination IP address field of the received uplink packet is matched with the destination IP address in the acquired identification information;

the received route identifier included in the uplink packet is matched with the backhaul adaptive protocol BAP route identifier in the acquired identification information;

matching the BAP address included in the received uplink packet with the BAP address in the acquired identification information;

matching the flow label in the IP header of the received uplink packet with the flow label in the acquired identification information; or

And matching the differential service code point value in the IP header of the received uplink packet with the directory service code point in the acquired identification information.

14. A method, comprising:

receiving, at a first device, a request from a second device to establish at least one tunnel between the first device and a third device;

15. The method of claim 14, wherein the at least one tunnel comprises a first tunnel and the tunnel information comprises at least one of the following for the first tunnel:

an internet protocol address of the first device,

identification of a tunnel endpoint associated with the first tunnel, or

A format of the at least one uplink packet.

16. The method of claim 14, wherein the at least one uplink packet targeting the first device includes at least one of the following identifications associated with the first device:

the source Internet Protocol (IP) address of the source,

the destination IP address is set to a value that is,

the back-haul adaptation protocol (BAP) address,

the identification of the BAP route is identified,

flow labels, or

Differentiated services code points.

17. The method of claim 14, wherein the request indicates at least one of:

a format of the at least one uplink packet, or

A number of the at least one tunnel to establish.

18. A method, comprising:

sending, from a second device to a first device, a request for establishing at least one tunnel between the first device and a third device, for forwarding, from the third device to the first device, at least one uplink packet from a fourth device targeted to the first device;

19. A method, comprising:

obtaining, at a third device, tunnel information from a second device regarding at least one tunnel to be established between the third device and a first device;

obtaining, from the second device, identification information regarding at least one uplink packet, the at least one uplink packet being from a fourth device and targeted for the first device, and the at least one uplink packet to be forwarded to the first device via the at least one tunnel and the third device; and

20. A first apparatus comprising means for:

receiving, from a second apparatus, a request to establish at least one tunnel between the first apparatus and a third apparatus;

transmitting tunnel information regarding the at least one tunnel to be established between the first device and the third device to the second device; and

receiving, from a fourth device via the third device and the at least one tunnel, at least one uplink packet targeted for the first device.

21. A second apparatus comprising means for:

sending a request to a first apparatus for establishing at least one tunnel between the first apparatus and a third apparatus for forwarding from the third apparatus to the first apparatus at least one uplink packet from a fourth apparatus targeted to the first apparatus;

receiving tunnel information regarding the at least one tunnel from the first device;

providing, to the third apparatus, identification information regarding at least one uplink packet to be forwarded from the third apparatus to the first apparatus through the at least one tunnel.

22. A third apparatus comprising means for:

obtaining, from the second apparatus, identification information regarding at least one uplink packet, the at least one uplink packet being from a fourth apparatus and targeted for the first apparatus, and the at least one uplink packet to be forwarded to the first apparatus via the at least one tunnel and the third apparatus; and

23. A computer-readable medium comprising program instructions that, when executed by at least one processor, cause an apparatus to at least perform the method of any of claims 14-17.

24. A computer-readable medium comprising program instructions that, when executed by at least one processor, cause an apparatus to at least perform the method of claim 18.

25. A computer-readable medium comprising program instructions that, when executed by at least one processor, cause an apparatus to at least perform the method of claim 19.