Method for 5g LAN ethernet multicast group management and traffic forward

Abstract

The invention discloses a method for adding UE (User Equipment) into a multicast group in a 5G local area network. The method comprises the following steps: processing a multicast group joining request message received from UE in a 5G local area network at a UPF of a 5G core network to obtain a multicast group IP address; converting the multicast group IP address into a multicast group MAC address; and adding the UE into the multicast group according to the multicast group MAC address.

Description

SMF 24 MEM UDM 26 <---> IMM 5G RAN 16 18 6 0) Leave Group mes -.-- sage • \r, Join Group message e e *-1 0 I0 Data Center (DN) 20 I:PF 22 <-31. UE4 5G LAN UE5 17E6\ , / 12B EI .=• 12-' • UE2 UE- 3 --c• 12A 14 GTP ti I GIP-1) Payload Ethernet Header 1P Header 1(1MP Header (12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) (19) World Intellectual Property Organization International Bureau (43) International Publication Date WO 2026 / 143758 Al 09 July 2026 (09.07.2026) WIPO I PCT 1111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111 (10) International Publication Number (51) International Patent Classification: H04W 0 / 06 (2009.01) (21) International Application Number: PCT / CN2025 / 071345 (22) International Filing Date: 08 January 2025 (08.01.2025) (25) Filing Language: English (26) Publication Language: English (30) Priority Data: 19 / 004,874 30 December 2024 (30.12.2024) US (71) Applicant: HONG KONG APPLIED SCIENCE ANDTECHNOLOGY RESEARCH INSTITUTE COMPA- NY LIMITED [CN / CN]; 5 / F, Photonics Centre, 2 Science Park East Avenue, Hong Kong Science Park, Shatin, N.T., Hong Kong (CN). (72) Inventors: LIU, Min; Flat G, 22 / F, Tower 2, The Riv- er Park, Mei Tin Street, Sha Tin, NT, Hong Kong (CN). ZHANG, Jianjun; Guangdong, China Post Office Address Futian District, Shenzhen, Guangdong 518000 (CN). XIA, Liang; Karig Le Building, Nanshan Road, Nanshan District, Shenzhen, Guangdong 518000 (CN). LI, Wei; Flat B, 15 / F, Block 5, Royal Ascot No.1 Tsun King Road, Sha Tin, NT, Hong Kong (CN). DONG, Liang; 27c, Block 6 Metro City Phase II, No. 8 Yan King Road, Tseung Kwan 0, Hong Kong (CN). TSANG, Yau Yau Yolanda; Flat A, 4 / F, Roca Centre, Block 2, 466 King's Road, North Point, Hong Kong (Cm. (74) Agent: CHINA TRUER IP; Room 1104, Building 2, Excellence Meilin Central Plaza (North Area), No. 128 Zhongkang Road, Meidu Community, Meilin Street, Futian District, Shenzhen, Guangdong 518049 (CN). (81) Designated States(unless otherwise indicated, for every kind of national protection available): AE, AG, AL, AM, AO, AT, AU, AZ, BA, BB, BG, BH, BN, BR, BW, BY, BZ, CA, CH, CL, CN, CO, CR, CU, CV, CZ, DE, DJ, DK, DM, DO, DZ, EC, EE, EG, ES, FI, GB, GD, GE, GH, GM, GT, HN, HR, HU, ID, IL, IN, IQ, IR, IS, IT, JM, JO, JP, KE, KG, KH, ICN, KP KR, KW, KZ, LA, LC, LK, LR, LS, LU, LY, MA, MD, MG, MK, MN, MU, MW, MX, MY, MZ, NA, NG, NI, NO, NZ, OM, PA, PE, PG, PH, PL, PT, QA, RO, RS, RU, RW, SA, SC, SD, SE, SG, SK, SL, ST, SV, SY, TH, (54) Title: METHOD FOR 5G LAN ETHERNET MULTICAST GROUP MANAGEMENT AND TRAFFIC FORWARDING IP He:ukr t :DP Hezpier G.rp-l;Fic4dor Giv_LIP;33,load Ethernet Header 11% TP Header IGNIP Header IMO -0'!" ir; N F9) Fig. 2 ql• 11 (57) Abstract: A method of joining a UE to a multicast group in a 5G LAN. The method comprises, at a UPF of a 5G core network, el performing the steps of processing a multicast group join request message received from the UE in the 50 LAN to obtain a Multicast CZGroup IP address; convening the Multicast Group IP address into a multicast group MAC address; and joining the UE to the multicast N group based on said multicast group MAC address. [Continued on next page] WO 2026 / 143758 A11111111 111111111111111 1111111 11111111111111111111111111111111111111 II I 111111111 111111 TJ, TM, TN, TR, TT, TZ, UA, UG, US, UY, UZ, VC, VN, WS, ZA, ZM, ZW. (84) Designated States (unless otherwise indicated, for every kind of regional protection available): ARIPO (BW, CV, GH, GM, KE, LR, LS, MW, MZ, NA, RW, SC, SD, SL, ST, SZ, TZ, UG, ZM, ZW), Eurasian (AM, AZ, BY, KG, KZ, RU, TJ, TM), European (AL, AT, BE, BG, CH, CY, CZ, DE, DK, EE, ES, FI, FR, GB, GR, HR, HU, IE, IS, IT, LT, LU, LV, MC, ME, MK, MT, NL, NO, PL, PT, RO, RS, SE, SI, SK, SM, TR), OAPI (BF, BJ, CF, CG, CI, CM, GA, GN, GQ, GW, KM, ML, MR, NE, SN, TD, TG). Published: — with international search report (Art. 21(3)) WO 2026 / 143758 PCT / CN2025 / 071345 METHOD FOR 5G LAN ETHERNET MULTICAST GROUPMANAGEMENT AND TRAFFIC FORWARDING Field of the Invention. The invention relates to a 5G Local Area Network (LAN). In particular, the present 5 invention relates to 5G LAN Ethernet multicast group management and traffic forwarding. More specifically, the invention relates to a method of joining a terminal such as a UE to a multicast group in a 5G LAN, releasing or removing a UE from the multicast group, and / or forwarding multicast packets to UEs in the multicast group. 10 Background of the Invention. 5G LAN is a virtual LAN service built in a 5G network, through which a LAN with mobility can be assembled to meet, for example, production or office needs, etc. In a 5G network, the administrator can modify the data in the user database to contract services to specified terminal (UE) numbers, thus grouping them into a 5G LAN. 5G LAN 15 capabilities provide industry users, for example, with support for wide-area mobile local area networks and VPN services including Ethernet Forwarding;Broadcast / Multicast; UE- to-UE Communication; and Group Management. 5G LAN supports Ethernet traffic, and 5G networks can directly transmit Layer 2 protocols. The User Plane Function (UPF) should recognize the Media Access Control 20 (MAC) addresses of terminals and support the forwarding of Ethernet multicast traffic. The two-layer networking provided by 5G LAN enables industrial users to facilitate efficient communication and isolation between devices, meeting the special requirements of industrial communication and improving the intelligence and automation of industrial production. Multicast is widely used in industrial scenarios. This is because 25 multicast / broadcast can achieve distributed control and management, thereby improving production efficiency and quality. 5G LAN supports multicasting, which can realize more efficient and reliable production line control and management. Industry verticals have very low latency requirements for Ethernet multicast forwarding. Without anefficient 5G LAN multicast function, the 5G system cannot 30 perform well in low-latency-sensitive 5G private networks, particularly in 5G factories. 3GPP specifications and existing solutions do not provide an efficient implementation method for 5G LAN multicast group management and forwarding. Therefore, there is a need, among other things, to implement a novel method for forwarding multicast traffic and managing multicast groups efficiently in 5G LANs. 1 WO 2026 / 143758 PCT / CN2025 / 071345 Objects of the Invention. An object of the invention is to mitigate or obviate to some degree one or more problems associated with known methods of forwarding multicast traffic and managing multicast groups efficiently in 5G LANs. 5 The above object is met by the combination of features of the main claims; the sub- claims disclose further advantageous embodiments of the invention. Another object of the invention is to provide a novel method and system of joining a UE to a multicast group in a 5G LAN.A further object is to provide a novel method and system of a UE leaving a 10 multicast group in a 5G LAN. A yet further object of the invention is to provide a novel method of forwarding multicast packets to UEs in a multicast group. One skilled in the art will derive from the following description other objects of the invention. Therefore, the foregoing statements of object are not exhaustive and serve 15 merely to illustrate some of the many objects of the present invention. Summary of the Invention. The invention provides a system and method for 5G LAN Ethernet multicast group management and traffic forwarding on the 5G data plane which is a key step for further 20 supporting 5G network for smart manufacturing and the like. In a first main aspect, the invention provides a method of joining a UE to a multicast group in a 5G LAN. The method comprises, at a UPF of a 5G core network, performing the steps of processing a multicast group join request message received from the UE in the5G LAN to obtain a Multicast Group IP address; converting the Multicast 25 Group IP address into a multicast group MAC address; and joining the UE to the multicast group based on said multicast group MAC address. In a second main aspect, the invention provides a method of a UE leaving the 5G LAN multicast group comprising receiving at the UPF a UE multicast group leave request message, processing the multicast group leave request message to obtain a Multicast Group 30 IP address, converting the Multicast Group IP address into a multicast group MAC address / Multicast Group identifier (ID), using the F-SEID and UE MAC address for mapping to the Multicast Group ID in the 5G multicast hash table and, if a mapping is found in the 5G multicast hash table, comparing the Multicast Group ID in the multicast hash table entry to the Multicast Group ID obtained from the preceding conversion step 2 WO 2026 / 143758 PCT / CN2025 / 071345 and, if the same, i.e., if matched, the UPF deletes the UE from theMulticast Group UE list sharing said mapped multicast group MAC address / Multicast Group ID. The UPF then deletes a corresponding hash key for the deleted UE from the 5G multicast hash table. In a third main aspect, the invention provides a method of forwarding a multicast 5 packet received from a UE at a 5G data plane of a 5G core network, the method comprising: receiving the multicast packet at a UPF in the 5G core network; the UPF configured to process the multicast packet to obtain a UE MAC address and UE F-SEID for said UE; the UPF configured to use the UE MAC address and UE F-SEID to look-up a 5G multicast hash table to find a Group UE list of an associated multicast group; and the 10 UPF configured to duplicate the multicast packet and forward the multicast packet to other UEs in the associated multicast group. In a fourth main aspect, the invention provides a network node in a 5G core network, the network node configured to perform a UPF of the 5G core network and configured toimplement any of the methods of the first to third main aspects of the 15 invention. In a fifth main aspect, the invention provides a non-transitory computer-readable medium storing machine-readable instructions, wherein, when the machine-readable instructions are executed by a processor, they configure the processor to implement any of the methods of the first to third main aspects of the invention. 20 The summary of the invention does not necessarily disclose all the features essential for defining the invention; the invention may reside in a sub-combination of the disclosed features. The foregoing has outlined fairly broadly the features of the present invention in order that the detailed description of the invention which follows may be better understood. 25 Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It will be appreciated by those skilled in the art that the conception and specificembodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the invention. 30 Brief Description of the Drawings. The foregoing and further features of the present invention will be apparent from the following description of preferred embodiments which are provided by way of example only in connection with the accompanying figures, of which: 3 WO 2026 / 143758 PCT / CN2025 / 071345 Fig. 1 illustrates the known 3GPP 5G standalone service-based architecture (SBA); Fig. 2 illustrates a 5G LAN comprising a virtual LAN service provisioned on a 5G network; Fig. 3 illustrates issues which arise in implementing 5G LAN multicast forwarding 5 and 5G LAN multicast management; Fig. 4 is a flow diagram of a method of joining a terminal (UE) to a multicast group in a 5G LAN in accordance with the invention; Fig. 5 illustrates the structure of a 5G multicast hash table for a UE joining a multicast group in a 5G LAN in accordancewith the invention; 10 Fig. 6 illustrates the 5G multicast hash table for a UE leaving a multicast group in a 5G LAN in accordance with the invention; Fig. 7 illustrates multicast packet forwarding in a 5G LAN in accordance with the invention; Fig. 8 shows a method and corresponding 5G multicast hash table for multicast 15 packet forwarding in a 5G LAN in accordance with the invention; and Fig. 9 is a flow diagram of the method of multicast packet forwarding in the 5G LAN in accordance with the invention. Description of Preferred Embodiments. 20 The following description is of preferred embodiments by way of example only and without limitation to the combination of features necessary for carrying the invention into effect. Reference in this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the 25 embodiment is included in at least one embodiment of the invention. The appearances of the phrase"in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Moreover, various features are described which may be exhibited by some embodiments and not by others. Similarly, various requirements 30 are described which may be requirements for some embodiments, but not other embodiments. It should be understood that the elements shown in the drawings may be implemented in various forms of hardware, software, or combinations thereof. These elements may be implemented in a combination of hardware and software on one or more 4 WO 2026 / 143758 PCT / CN2025 / 071345 appropriately programmed general-purpose devices, which may include a processor, memory, and input / output interfaces. The present description illustrates the principles of the present invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements5 that, although not explicitly described or shown herein, embody the principles of the invention and are included within its spirit and scope. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such 10 equivalents include both currently known equivalents as well as equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure. Thus, for example, it will be appreciated by those skilled in the art that the block diagrams presented herein represent conceptual views of systems and devices embodying 15 the principles of the invention. The functions of the various elements shown in the figures may be provided through the use of dedicated hardware as well as hardware capable of executing software in association with appropriate software.When provided by a processor, the functions may be provided by a single dedicated processor, by a single shared processor, or by a plurality 20 of individual processors, some of which may be shared. Moreover, explicit use of the term "processor" or "controller" should not be construed to refer exclusively to hardware capable of executing software, and may implicitly include, without limitation, digital signal processor ("DSP") hardware, read-only memory ("ROM") for storing software, random access memory ("RAM"), and non-volatile storage. 25 In the claims hereof, any element expressed as a means for performing a specified function is intended to encompass any way of performing that function including, for example, a) a combination of circuit elements that performs that function or b) software in any form, including, therefore, firmware, microcode, or the like, combined with appropriate circuitry for executing that software to perform the function. The invention as 30 defined by suchclaims resides in the fact that the functionalities provided by the various recited means are combined and brought together in the manner which the claims call for. It is thus regarded that any means that can provide those functionalities are equivalent to those shown herein. 5 WO 2026 / 143758 PCT / CN2025 / 071345 The following description describes implementation of the present invention in a 5G communications network by way of example, but without limitation to implementation of the invention in suitable communications networks. 5G LANs are private cellular networks typically provided for enterprises that 5 integrate into an organization's existing infrastructure. They provide high-speed wireless access and deterministic performance for mission-critical applications. 5G LANs can reduce the use of Ethernet cables, for example. A 5G LAN uses 5G terminal access capability and a private mobile LAN service to provide flexible communication services for group member terminals. 5G terminals,also known as 5G Customer Premise 10 Equipment (CPE), enable devices like computers, laptops, and mobile phones to connect to the intemet. 5G CPE devices receive 5G signals from a base station and then convert them into Wi-Fi or wired signals. References herein to "UEs", "CPEs" are to be taken to be references to "terminals" and vice-versa. 15 Referring to the drawings, Fig. 1 illustrates the known 3GPP 5G standalone service-based architecture (SBA) including the known interfaces between nodes and / or functional elements of the 5G network. Fig. 2 illustrates a 5G network 10 including one or more virtual network (VN) Groups in a 5G LAN 12. Each VN Group comprises a virtual LAN service provisioned on 20 the 5G network 10. In Fig. 2, UE1 to UE3 comprise a first VN Groupl2A and UE4 to UE6 comprise a second VN Groupl2B. The first and second VN Groups12A, B are connected wirelessly to a core network 14 of the 5G network 10 by a radio access network (RAN) 16 including one or more base stations18. The core network 14 may be connected to one or more data centers or data networks (DNs) 20. The core network 10 includes functional 25 entities including a UPF 22, a session management function (SMF) 24, and a Unified Data Management (UDM) function 26. The functional entities may be implemented in core network nodes such as servers or the like configured to implement the respective functions through execution by one or more processors of machine-readable instructions stored on one or more non-transitory computer-readable media. 30 Fig. 3 illustrates an example embodiment of an enterprise based 5G LAN for managing and / or controlling industrial machines, e.g., programmable logic controllers (PLCs), and / or processes which give rise to issues in implementing 5G LAN multicast forwarding and 5G LAN multicast management. 6 WO 2026 / 143758 PCT / CN2025 / 071345 Industry verticals have very low latency requirements for Ethernet multicast forwarding. Without an efficient 5G LAN multicastfunction, the 5G system cannot perform well in low-latency-sensitive 5G private networks, particularly in 5G factories. 3GPP specifications and existing solutions do not provide an efficient implementation 5 method for 5G LAN multicast group management and forwarding. The issues addressed by the present invention are to implement a novel method for forwarding multicast traffic and managing multicast group efficiently in 5G LAN and to implement an efficient 5G LAN multicast group management as will be hereinafter explained. The key embodiments of the invention addressing these issues comprise a novel 10 method for a UE to join a 5G LAN multicast group, a novel method for a UE to leave a 5G LAN multicast group, and a novel method for multicast traffic forwarding. The novel method of joining a UE to a 5G LAN multicast group comprises the UPF 22 processing a multicast group join request message received from the UE in the 5G LAN to obtain a multicast group internet protocol (IP) address,converting the Multicast Group 15 IP address into a multicast group MAC address, and joining the UE to the multicast group based on said multicast group MAC address. When the 5G core network 14 and the 5G RAN 16 are correctly setup and ready, the UE (UE1 in the case of Figs. 2, 4 and 5) accesses the 5G RAN 16 and an Ethernet Protocol Data Unit (PDU) session is established in the UPF 22 for the UE. If the UE 20 wishes to join a multicast group, the UE sends a multicast group join request message. As seen in Fig. 2, the multicast group join request message received by the UPF 22 from the UE comprises an Internet Group Management Protocol (IGMP) join group request message which is carried in a GPRS Tunneling Protocol for User Plane (GTP-U) payload accompanied by a GTP-U Header, a User Data Plane (UDP) Header, and an IP Header. An 25 IGMP Header follows with an Ethernet Header transported to the UPF 22 by a GTP-U tunnel. The UPF 22 receives the IGMP group join request and, in response,adds an entry for the UE in a 5G Multicast Hash Table thereby joining the UE to the requested multicast group. Fig. 4 illustrates in more detail the steps of the novel method 30 taken to join the 30 UE to the requested multicast group. In a first step 31 of the method 30, the UPF 22 receives the IGMP join group request message from the UE. In a next step 32 of the method 30, the UPF 22 decodes the Forwarding Tunnel Endpoint Identifier (F-TEID) for the UE in the GTP-U Header and finds the UPF Fully Qualified Session Endpoint Identifier (F-SEID). In a next step 33 of 7 WO 2026 / 143758 PCT / CN2025 / 071345 the method 30, the UPF 22 decodes the UE MAC address (UE1 MAC address in this example). Then, in a next step 34, the UPF 22 decodes the IGMP Header to obtain the Multicast Group IP address. In a following step 35, the UPF 22 converts the Multicast Group IP address into a multicast group MAC address and sets it as the Multicast Group 5 identifier (ID). In a next step 36, based on themulticast group MAC address / Multicast Group ID, the UPF 22 adds the UE (UE1) to the multicast Group UE List. Then, in a final step 37 of the method 30, the UPF 22 adds a hash key and a value to the 5G Multicast Hash Table. Fig. 5 shows a structure of the 5G multicast hash table for the UE joining the 10 multicast group in the 5G LAN. The hash key is based on a combination of the UE MAC address and UPF F-SEID. The value comprises the Multicast Group ID / Group UE List. The step of converting the Multicast Group IP address into a multicast group MAC address and setting it as the Multicast Group ID preferably comprises the following sub- steps. A first sub-step comprises converting the Multicast Group IP address to a binary 15 string of bits. For example, where the Multicast Group IP address comprises the address 239.0.1.1, the binary bit string comprises 11101111.00000000.00000001.00000001. A next sub-step comprises extracting the last 23 bits, i.e., the underlined bits shown here11101111.00000000.00000001.00000001. Then in a next sub-step, the last 23 binary bits are appended to binary bits comprising fixed bits of a known MAC address prefix reserved 20 for multicasting. The fixed bits of the MAC address prefix reserved for multicasting comprise the 25 binary bits 00000001.00000000.01011110.0. Consequently, the resultant string of binary bits comprises 00000001.00000000.01011110.00000000.00000001.00000001. In a next sub-step, the resultant string of binary bits is converted to hexadecimal to provide the multicast group 25 MAC address that is used when transmitting multicast traffic packets to the UEs comprising the Group UE list of the multicast group. In this example, the hexadecimal form of the multicast group MAC address is HEX: Ox0100.5E00.0101 as seen in Fig. 5. This is the MAC address that will be used when transmitting to group 239.0.1.1, and it is also the Multicast Group ID in the 5G Multicast Hash Table. 30 The novel method of a UE leaving the 5G LANmulticast group comprises receiving at the UPF 22 a UE multicast group leave request message, processing the multicast group leave request message to obtain a Multicast Group IP address, converting the Multicast Group IP address into a multicast group MAC address / Multicast Group ID, using the F-SEID and UE MAC address for mapping to the Multicast Group ID in the 5G 8 WO 2026 / 143758 PCT / CN2025 / 071345 multicast hash table and, if a mapping is found in the 5G multicast hash table, comparing the Multicast Group ID in the multicast hash table entry to the Multicast Group ID obtained from the preceding conversion step and, if the same, the UPF 22 deletes the UE from the Multicast Group UE list sharing said mapped multicast group MAC 5 address / Multicast Group ID. The UPF 22 then deletes a corresponding hash key for the deleted UE from the 5G multicast hash table. As seen in Fig. 2, the multicast group leave request message received by the UPF 22 from the UE has a same structure as themulticast group join request message. More specifically, the method of a UE leaving the multicast group comprises the 10 following steps. In a first step, if the UE (e.g. UE1) wishes to leave the multicast group, the UE sends an IGMP leave group request message to the UPF 22 with the IGMP header following with IP / Ethernet Header transport by GTP-U tunnel. In a next step, the UPF 22 decodes the F-TEID in the GTP-U Header and finds the UPF F-SEID. In a next step, the UPF 22 decodes the Ethernet Header to obtain the UE MAC address. Following this, in a 15 next step, the UPF 22 decodes IGMP Header to obtain the Multicast Group 1P address and then converts the Multicast Group 1P Address into the multicast group MAC Address and derives the Multicast Group ID therefrom. In a next step, the UPF 22 uses the UPF F-SEID and the UE MAC Address as a key to map to the Multicast Group ID from the 5G Multicast Hash Table to check if the Multicast Group ID from the prior step is the same as 20 theMulticast Group ID from the 5G Multicast Hash Table. If the mapped Multicast Group IDs are the same, the UPF 22 deletes the UE (UE1) entry from the Group UE list for the corresponding multicast group and then deletes the respective hash key entry in the 5G Multicast Hash Table as can be seen in Fig. 6. As illustrated in Fig. 7, the novel method of multicast traffic forwarding comprises, 25 upon receiving a multicast packet from the UE on a 5G data plane of the 5G core network, the UPF 22 uses the UE MAC address and UE F-SEID as a hash key to map to a Multicast Group ID in the 5G multicast hash table and, if the hash key maps to a Multicast Group ID, the UPF 22 duplicates the multicast packet and forwards the multicast packet to other UEs in the Multicast Group UE list sharing said mapped Multicast Group ID. The UPF 22 30 obtains the UE MAC address and UE F-SEID from the multicast packet received from the UE on the 5G data plane. Fig. 8 illustrates an embodiment of the method ofmulticast traffic forwarding with the corresponding 5G Multicast Hash Table. Fig. 9 comprises a flow diagram of a more detailed version of the method 40 illustrated by Fig. 8. 9 WO 2026 / 143758 PCT / CN2025 / 071345 In a first step 41 of the method 40 of Fig. 9, the UPF 22 receives the multicast Ethernet packet from, for example, UE1, decodes the F-TEID in the GTP-U Header to obtain the UPF F-SEID and then the UPF 22 decodes the UE (UE1) MAC address. In a next optional step 42, the UPF performs a Packet Detection Rule (PDR) detection to check 5 if the UE belongs to the 5G LAN. If not, the method is terminated. If yes, then, in a next step 43, the UPF 22 uses the UE MAC address and UPF F-SEID as a hash key to map to the 5G Multicast Hash Table and obtain the Multicast Group ID. In a next step 44, the UPF checks if the obtained Multicast Group ID is the same as the multicast packet destination of the MAC address and, if not, the method is terminated. However, if yes, then, in a next 10 step45, the UPF 22 duplicates the multicast Ethernet packet and forwards the multicast Ethernet packet to the or any UEs which are in the same Multicast Group UElist, e.g., UE2 and UE3 in the example of Figs 7 and 8. The invention provides an apparatus and a method for 5G LAN Ethernet multicast group management and traffic forwarding on 5G data plane, the method for joining a 5G 15 LAN multicast group comprising the steps of: receiving the 5G LAN user configurations configured from the UDM on SMF; establishing an up Ethernet PDU session for the UE on UPF; accessing the 5G LAN network with the Ethernet PDU session from UE; on receiving an IGMP multicast group join request from the UE, the UPF decodes the IGMP message; and the UPF adds an entry in the 5G Multicast Group Hash Table on UPF. 20 The UDM or Unified Data Repository (UDR) may store key 5G LAN user data including VN Group ID, data network name (DNN), Single Network Slice Selection Assistance Information (SNSSAI), and group members,etc. The SMF may request 5G LAN user data from the UDM on the N10 interface by using the HTTP / 2 protocol. 25 The SMF may send Session Establishment Request with Ethernet PDN type to the UPF by the N4 interface through the Packet Forwarding Control Protocol (PFCP) protocol, and then the UPF may establish the Ethernet PDU Session for the 5G LAN UE. The UPF preferably receives the IGMP join request encapsulated by GTP-U from the UE on the established Ethernet PDU Session from the N3 interface, then decodes GTP- 30 U encapsulation, and finds the F-TEID in the GTP-U header. Preferably, the UPF further decodes the UE MAC address in the Ethernet Header and the Multicast Group IP address in the IGMP Header of the GTP-U payload. The UPF may lookup the PFCP session by using the F-TEID. 10 WO 2026 / 143758 PCT / CN2025 / 071345 Preferably, the UPF converts the Multicast Group IP decoded from the IGMP Header decapsulated from the GTP-U packet to the Multicast Group ID for the 5G LAN group management.The UPF may first convert the Multicast Group IP address to binary, take the last 5 23 bits and add it to the 25 bits of the well-known multicast MAC prefix, then convert it to HEX to get the Multicast Group ID. The UPF adds a new entry in the 5G Multicast Hash Table, with the hash table key as the combination of the UE MAC address and the UPF F-SEID and the hash table entry as the Multicast Group ID and Group UE List. 10 The invention provides an apparatus and a method for 5G LAN Ethernet multicast group management and traffic forwarding on 5G data plane, the apparatus configured to implement the method for leaving the 5G LAN multicast group comprising the steps of: accessing the 5G LAN network with the Ethernet PDU Session on the UE; on receiving an IGMP multicast group leave request from the UE, the UPF decodes the IGMP message and 15 then deletes the entry in the 5G Multicast Group Hash Table on the UPF. The UPF may receive the IGMP leave request encapsulated by GTP-U from the UEon the established Ethernet PDU Session from the N3 interface, then decodes the GTP-U encapsulation, and finds the F-TEID in the GTP-U Header. The UPF may further decode the UE MAC address in the Ethernet header and the 20 Multicast Group IP address in the IGMP header of the GTP-U payload. The UPF preferably lookups the UPF F-SEID by using the F-TEID. The UPF preferably converts the Multicast Group IP address decoded from the IGMP Header decapsulated from the GTP-U packet to the Multicast Group ID for the 5G LAN group management. 25 The UPF preferably first converts the Multicast Group IP to binary bits, takes the last 23 bits and add these to the 25 bits comprising the well-known multicast MAC prefix, then convert the resulting bit string to HEX to get the Multicast Group ID. The UPF uses the UPF F-SEID and the UE MAC address to lookup the entry in the 5G Multicast Hash Table and compares the Multicast Group ID in the entry to the 30 Multicast Group ID of the preceding paragraph. TheUPF deletes the UE from the Group UE list in the entry from the 5G Multicast Hash Table if the Multicast Group IDs match. The invention provides an apparatus and a method for 5G LAN Ethernet multicast group management and traffic forwarding on 5G data plane, supports multiple UPF 11 WO 2026 / 143758 PCT / CN2025 / 071345 deployments, and allows multicast group traffic to be transmitted within one UPF. The method for traffic forwarding comprises the steps of: accessing the 5G LAN network with the Ethernet PDU Session on the UE; on receiving a multicast packet from the UE, the UPF decodes the GTP-U message; the UPF finds the Group UE list in the 5G Multicast 5 Hash Table; the UPF duplicates the multicast group traffic packet; and the UPF forwards the multicast group traffic packet to the other UEs in the same Group UE list. The UPF preferably receives the Multicast packet encapsulated by GTP-U from the UE on the established Ethernet PDU Session from the N3 interface, then decodes the GTP- Uencapsulation, and finds the F-TE1D in the GTP-U header. 10 The UPF preferably lookups the UPF F-SEID by using the F-TEID. The UPF preferably decodes the UE MAC address in the Ethernet header and the Multicast Group IP address in the IGMP header of the GTP-U payload. The UPF preferably uses the UPF F-SEID and the UE MAC address to lookup the entry in the 5G Multicast Hash Table and finds the Group UE list in the 5G Multicast Hash 15 Table. The UPF duplicates the multicast traffic for all other UEs in the same multicast group. The data structure of the 5G Multicast Hash Table preferably comprises a hash key consisting of the UE MAC and the UPF F-SEID and a value consisting of the Multicast 20 group ID and the Group UE list belonging to the same multicast group. The invention also provides a non-transitory computer-readable medium storing machine-readable instructions, wherein, when the machine-readable instructions are executed by a processor, they configure the processor to implementthe method of any one of the appended method claims. 25 The apparatus described above may be implemented at least in part in software. Those skilled in the art will appreciate that the apparatus described above may be implemented at least in part using general purpose computer equipment or using bespoke equipment. Here, aspects of the methods and apparatuses described herein can be executed on 30 any apparatus comprising the communication system. Program aspects of the technology can be thought of as "products" or "articles of manufacture" typically in the form of executable code and / or associated data that is carried on or embodied in a type of machine- readable medium. "Storage" type media include any or all of the memory of the mobile stations, computers, processors or the like, or associated modules thereof, such as various 12 WO 2026 / 143758 PCT / CN2025 / 071345 semiconductor memories, tape drives, disk drives, and the like, which may provide storage at any time for the softwareprogramming. All or portions of the software may at times be communicated through the Internet or various other telecommunications networks. Such communications, for example, may enable loading of the software from one computer or 5 processor into another computer or processor. Thus, another type of media that may bear the software elements includes optical, electrical, and electromagnetic waves, such as used across physical interfaces between local devices, through wired and optical landline networks and over various air-links. The physical elements that carry such waves, such as wired or wireless links, optical links, or the like, also may be considered as media bearing 10 the software. As used herein, unless restricted to tangible non-transitory "storage" media, terms such as computer or machine "readable medium" refer to any medium that participates in providing instructions to a processor for execution. While the invention has been illustrated and described in detail in thedrawings and foregoing description, the same is to be considered as illustrative and not restrictive in 15 character, it being understood that only exemplary embodiments have been shown and described and do not limit the scope of the invention in any manner. It can be appreciated that any of the features described herein may be used with any embodiment. The illustrative embodiments are not exclusive of each other or of other embodiments not recited herein. Accordingly, the invention also provides embodiments that comprise 20 combinations of one or more of the illustrative embodiments described above. Modifications and variations of the invention as herein set forth can be made without departing from the spirit and scope thereof, and, therefore, only such limitations should be imposed as are indicated by the appended claims. In the claims which follow and in the preceding description of the invention, except 25 where the context requires otherwise due to express language or necessaryimplication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e., to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention. It is to be understood that, if any prior art publication is referred to herein, such 30 reference does not constitute an admission that the publication forms a part of the common general knowledge in the art. 13 WO 2026 / 143758 PCT / CN2025 / 071345 Claims 1. A method of joining a user equipment (UE) to a multicast group in a 5G local area network (LAN), the method comprising: 5 at a network node configured to perform a user plane function (UPF) of a 5G core network, performing the steps of: processing a multicast group join request message received from the UE in the 5G LAN to obtain a multicast group interne protocol (IP) address; converting the Multicast Group IP address into a multicast group media 10 access control(MAC) address; joining the UE to the multicast group based on said multicast group MAC address. 2. The method of claim 1, wherein the multicast group MAC address is set as the 15 Multicast Group identifier (ID), and the UE is added to the Multicast Group UE list. 3. The method of claim 2, wherein a hash table key based on a MAC address of the UE is added to a 5G multicast hash table for multicast groups. 20 4. The method of claim 3, wherein the hash table key based on the MAC address of the UE is based on a combination of the UE MAC address and a Fully Qualified Session Endpoint Identifier (F-SEID) obtained from a Protocol Data Unit (PDU) session established by the UPF for the UE. 25 5. The method of claim 4, wherein a hash table entry comprising the Multicast Group ID and the Multicast Group UE list is added to the 5G multicast hash table for the multicast groups. 6. The method of claim 1, wherein the step of converting the Multicast Group IP 30 address into the multicast group MACaddress comprises: converting the Multicast Group IP address to a string of binary bits; selecting a predetermined number of binary bits in a latter part of the string; appending the selected binary bits to a string of binary bits comprising fixed bits of a MAC address prefix reserved for multicasting; 14 WO 2026 / 143758 PCT / CN2025 / 071345 converting the resulting string of binary bits to hexadecimal to provide the multicast group MAC address that is used when transmitting multicast traffic packets to the UEs comprising the Group UE list of the multicast group. 5 7. The method of claim 6, wherein the predetermined number of binary bits selected from the latter part of the string of binary bits comprising the Multicast Group IP address comprise a last 23 binary bits of said string and wherein said selected 23 binary bits are added to 25 binary bits comprising the fixed bits of the MAC address prefix reserved for multicasting in the 5G LAN. 10 8. The method of claim 5, wherein, uponreceiving a multicast packet from the UE on a 5G data plane of the 5G core network, the UPF uses the UE MAC address and UE F- SEID as a hash key to map to a Multicast Group ID in the 5G multicast hash table and, if the hash key maps to a Multicast Group ID, the UPF duplicates the multicast packet and 15 forwards the multicast packet to other UEs in the Multicast Group UE list sharing said mapped Multicast Group ID. 9. The method of claim 8, wherein the UPF obtains the UE MAC address and UE F- SEID from the multicast packet received from the UE on the 5G data plane. 20 10. The method of claim 8, wherein, upon receiving the multicast packet from the UE on a 5G data plane, the UPF determines if the UE belongs to the 5G LAN and, if not, terminates the process. 25 11. The method of claim 5, further comprising: receiving at the UPF a UE multicast group leave request message; processing the multicast group leave request message to obtain a Multicast Group IP address; converting the MulticastGroup IP address into a multicast group MAC 30 address / Multicast Group ID; using the F-SEID and UE MAC address for mapping to the Multicast Group ID in the 5G multicast hash table and, 15 WO 2026 / 143758 PCT / CN2025 / 071345 if a mapping is found in the 5G multicast hash table, comparing the Multicast Group ID in the multicast hash table entry to the Multicast Group ID obtained from the preceding conversion step and, if the Multicast Group ID in the multicast hash table entry matches to the Multicast 5 Group ID obtained from the preceding conversion step, the UPF deletes the UE from the Multicast Group UE list sharing said mapped multicast group MAC address / Multicast Group ID. 12. The method of claim 11, wherein the UPF deletes a corresponding hash key for the 10 deleted UE from the 5G multicast hash table. 13. A method of forwarding a multicast packet received from a UE at a 5G data plane of a 5G core network, the method comprising: receiving the multicast packet at a UPF in the 5G corenetwork; 15 the UPF configured to process the multicast packet to obtain a UE MAC address and UE F-SEID for said UE; the UPF configured to use the UE MAC address and UE F-SEID to look-up a 5G multicast hash table to find a Group UE list of an associated multicast group; and the UPF configured to duplicate the multicast packet and forward the multicast 20 packet to other UEs in the associated multicast group. 14. A network node in a 5G core network, the network node configured to perform a user plane function (UPF) of the 5G core network and configured to: process a multicast group join request message received from a UE located in a 5G 25 LAN to obtain a multicast group internet protocol (IP) address, the 5G LAN connected to the 5G core network via a radio access network (RAN); convert the Multicast Group IP address into a multicast group media access control (MAC) address; and join the UE to the multicast group based on said multicast group MAC address. 30 16 WO 2026 / 143758PCT / CN2025 / 071345 1-4 en W-o 1 / 8 HE GCi :et O L.) .4-i r. LL D at a C en te r (D N ) 20 ■ WO 2026 / 143758 PCT / CN2025 / 071345 2 / 8 5 G C on tr ol R oo m L. "8 CL la O 1 I I I I I 5 G C o nt ro l P a n el a. WO 2026 / 143758 PCT / CN2025 / 071345 3 / 8 WO 2026 / 143758 PCT / CN2025 / 071345 30 Start 31 Multicast IGMP group join packet received Decode F-TEID Find UPF F-SEID 33 Decode UE1 MAC Address 34 35 36 Decode IGMP Header Get Multicast Group IP address Convert Multicast Group IP Address to Multicast Group ID Add UE1 to the Group UE list Add entry of the hash key (UE1 MAC address / UPF F-SEID) and value (Multicast Group ID / Group UE List) to the hash table END Fig. 4 4 / 8 Group List Table Kev HASH Gr:711p ID U1:2 00:59:00:0 1:01 0 1 :00:5e.00.0 1,02 <", 1'F5 ITti„ UE I MAC: l'PF Data Structure of 5G Multicast Hash Table Group t I'_ List 144 t E2 l E3.. l'E4 E5 1 E6.. WO 2026 / 143758 PCT / CN2025 / 071345 Fig. 5 Multicast packet destination MAC address HASH Hash Table Key Multicast Croup I!) UE1 MAC01:00;5e:00:01 AtEldfes.s :01 01:00:5e:00:01 .1.41E F SEED :02 HY•Ves re. Fig. 6 5 / 8 5G RAN 16 Multicast Traffic Packet UE3 UE1 U E2 Fig. 7 Data Center 20 UPF 22 WO 2026 / 143758 PCT / CN2025 / 071345 6 / 8 tE l M n it ic as P ac ke t O u f U E 3 M u lti ca si :‘,3••• " 4'4" ,•4 • •••••1 0 'A= 4 41 ".4 / 54 t U E 2 N bi lt ic as t WO 2026 / 143758 PCT / CN2025 / 071345 7 / 8 Start PDR Detect if UE belongs to 5G LAN Hash mapping, get Multicast Group ID 43 Multicast Group ID == multicast packet destination MAC address 44 yes • Duplicate multicast traffic, forward to UE(s) in the same Group UE List Fig. 9 no 41 Find UE session, decode UE MAC Address WO 2026 / 143758 PCT / CN2025 / 071345 40 8 / 8 INTERNATIONAL SEARCH REPORT International application No. PCT / CN2025 / 071345 A. CLASSIFICATION OF SUBJECT MATTER H04W4 / 06(2009.01)i According to International Patent Classification (IPC) or to both national classification and IPC B. FIELDS SEARCHED Minimum documentation searched (classification system followed byclassification symbols) IPC: HO4W,H04L Documentation searched other than minimum documentation to the extent that such documents are included in the fields searched Electronic data base consulted during the international search (name of data base and, where practicable, search terms used) CNTXT, WPABSC, 3GPP, ENTXTC, VEN, CJFD: user plane function, UPF, 5G LAN, multicast, group, IP address, MAC, UE, F-SEID, PDU, hash table, group ID C. DOCUMENTS CONSIDERED TO BE RELEVANT Category* Citation of document, with indication, where appropriate, of the relevant passages Relevant to claim No. X A A CN 115696223 A (HUAWEI TECHNOLOGIES CO LTD) 03 February 2023 (2023-02-03) description, paragraphs

[0153] -

[0201] CN 117479108 A (CHINA MOBILE COMMUNICATIONS CO LTD RES et al.) 30 January 2024 (2024-01-30) the whole document CN 113302880 A (TELEFONAKTIEBOLAGET ERICSSON L M) 24 August 2021 (2021-08-24) the whole document 1-3, 6-7, 14 1-14 1-14 Further documents are listed in the continuation of Box C.annex. I See patent family * Special categories of cited documents: "r' later document published after the international filing date or priority "A" document defining the general state of the art which is not considered date and not in conflict with the application but cited to understand the to be of particular relevance principle or theory underlying the invention "D" document cited by the applicant in the international application "X" document of particular relevance; the claimed invention cannot be "E" earlier application or patent but published on or after the international considered novel or cannot be considered to involve an inventive step filing date when the document is taken alone "L" document which may throw doubts on priority claim(s) or which is "Y" document of particular relevance; the claimed invention cannot be cited to establish the publication date of another citation or other considered to involve an inventive step when the document is special reason (as specified)combined with one or more other such documents, such combination -0" document referring to an oral disclosure, use, exhibition or other being obvious to a person skilled in the art means "&" document member of the same patent family "p" document published prior to the international filing date but later than the priority date claimed Date of the actual completion of the international search 17 September 2025 Date of mailing of the international search report 19 September 2025 Name and mailing address of the ISA / CN CHINA NATIONAL INTELLECTUAL PROPERTY ADMINISTRATION 6, Xitucheng Rd., Jimen Bridge, Haidian District, Beijing 100088, China Authorized officer FU,HaiWang Telephone No. (+86) 010-62411393 Form PCT / ISA / 210 (second sheet) (July 2022) INTERNATIONAL SEARCH REPORT Information on patent family members International application No. PCT / CN2025 / 071345 Patent document cited in search report Publication date (day / month / year) Patent family member(s) Publication date (day / month / year) CN115696223 A 03 February 2023 WO 2023006042 Al 02 February 2023 CN 117479108 A 30 January 2024 None CN 113302880 A 24 August 2021 JP 2023109789 A 08 August 2023 JP 7603098 B2 19 December 2024 WO 2020148062 Al 23 July 2020 EP 3895385 Al 20 October 2021 EP 3895385 B1 26 June 2024 US 2022150166 Al 12 May 2022 JP 2022517176 A 07 March 2022 JP 7274582 B2 16 May 2023 MX 2021008244 A 16 August 2021 BR 112021012912 A2 14 September 2021 Form PCT / ISA / 210 (patent family annex) (July 2022) (54) Invention Title: 5G LAN Ethernet Multicast Group Management and Traffic Forwarding Method (57) Abstract: A method for adding a UE to a multicast group in a 5G LAN. The method includes: at the UPF of the 5G core network, processing a multicast group join request message received from a UE in the 5G LAN to obtain a multicast group IP address; converting the multicast group IP address into a multicast group MAC address; and adding the UE to the multicast group according to the multicast group MAC address. (19) State Intellectual Property Office (12) Invention Patent Application (10) Publication Number CN 119968867 A (43) Publication Date 2025.05.09 (21) Application Number 202580000127.X (22) Application Date 2025.01.08 (30) Priority Data 19 / 004,874 2024.12.30 US (85) PCT International Application Entering National Phase Date 2025.02.06 (74) Patent Agency Shenzhen Xinchuangyou Intellectual Property Agency Co., Ltd. 44223 Patent Attorney Xie Linhong (51) Int.CI. H04W 4 / 06 (2009.01) H04W 5 / 26 (2009.01) H04W 847 / 2 (2009.01) (86) Application data for PCT international application: PCT / CN2025 / 071345 2025.01.08 (71)Applicant: Hong Kong Applied Science and Technology Research Institute Limited Address: 5 / F, Optoelectronics Centre, 2 Science Avenue East, Hong Kong Science Park, Shatin, New Territories, Hong Kong (72) Inventors: Liu Min, Zhang Jianjun, Xia Liang, Li Wei, Dong Liang, Zeng Youyou Claims: 2 pages Description: 8 pages Drawings: 8 pages V 2 , 9 8 00 9 6 6 1 1 3 CN 119968867 A Claims: f / 2 pages * 1. A method for adding a user equipment (UE) to a multicast group in a 5G local area network (LAN), the method comprising: at a network node configured to perform user plane functions (UPF) of a 5G core network, performing the following steps: processing a multicast group join request message received from the UE in the 5G LAN to obtain a multicast group Internet Protocol (IP) address; converting the multicast group IP address to a multicast group Media Access Control (MAC) address; adding the UE to the multicast group according to the multicast group MAC address. 2. The method of claim 1, wherein the multicast group MAC address is set as a multicast group identifier (ID), and the UE is added to the multicast group UE list. 3. The method of claim 2, wherein a hash table key based on the UE's MAC address is added to a 5G multicast hash table for the multicast group. 4. The method of claim 3, wherein the hash table key based on the UE's MAC address is a combination of the UE's MAC address and a Fully Qualified Session Endpoint Identifier (F-SEID), the F-SEID being obtained from a Protocol Data Unit (PDU) session established by the UPF for the UE. 5. The method of claim 4, wherein the multicast group ID and a hash table entry for the multicast group UE list are added to the 5G multicast hash table of the multicast group. 6. The method of claim 1, wherein the step of converting the multicast group IP address to the multicast group MAC address comprises: converting the multicast group IP address into a binary bit string; selecting a predetermined number of binary bits from the latter half of the bit string; appending the selected binary bits to a binary bit string containing fixed bits for a MAC address prefix reserved for multicast; and converting the resulting binary bit string to hexadecimal to provide the multicast group MAC address used when sending multicast traffic packets to UEs in the group UE list of the multicast group. 7. The method of claim 6, wherein the predetermined number of binary bits selected from the latter half of the binary bit string containing the multicast group IP address includes the last 23 binary bits of the bit string, and the selected 23 binary bits are added to 25 binary bits containing fixed bits for a MAC address prefix reserved for multicast in the 5G LAN. 8.According to claim 5, after receiving a multicast data packet from the UE on the 5G data plane of the 5G core network, the UPF uses the UE MAC address and the UE F-SEID as hash keys to map to a multicast group ID in the 5G multicast hash table. If the hash key maps to a multicast group ID, the UPF copies the multicast data packet and forwards it to other UEs in the multicast group UE list that share the mapped multicast group ID. 9. According to claim 8, the UPF obtains the UE MAC address and the UE F-SEID from the multicast data packet received from the UE on the 5G data plane. 10. According to claim 8, when the multicast data packet is received from the UE on the 5G data plane, the UPF determines whether the UE belongs to the 5G LAN; if not, the process is terminated. 11. The method of claim 5, further comprising: receiving a UE multicast group leave request message at the UPF; processing the multicast group leave request message to obtain a multicast group IP address; converting the multicast group IP address to a multicast group MAC address / multicast group ID; mapping the F-SEID and UE MAC address to the multicast group ID in the 5G multicast hash table; if a mapping is found in the 5G multicast hash table, comparing the multicast group ID in the multicast hash table entry with the multicast group ID obtained from the preceding conversion step; if the multicast group ID in the multicast hash table entry matches the multicast group ID obtained from the preceding conversion step, then the UPF deletes the UE from the list of multicast group UEs sharing the mapped multicast group MAC address / multicast group ID. 12. The method of claim 11, wherein the UPF deletes the corresponding hash key of the deleted UE from the 5G multicast hash table. 13. A method for forwarding multicast data packets received from a UE in the 5G data plane of a 5G core network, the method comprising: receiving the multicast data packets at a UPF in the 5G core network; the UPF being configured to process the multicast data packets to obtain the UE MAC address and UE F-SEID of the UE; the UPF being configured to use the UE MAC address and UE F-SEID to search a 5G multicast hash table to find a group UE list of a relevant multicast group; the UPF being configured to copy the multicast data packets and forward the multicast data packets to other UEs in the relevant multicast group. 14. A network node in a 5G core network, the network node being configured to perform a user plane function (UPF) of the 5G core network and being configured to: process data packets received from a UE in the 5G data plane of a 5G core network.The UE in the LAN receives a multicast group join request message to obtain the multicast group Internet Protocol (IP) address. The 5G LAN is connected to the 5G core network through a Radio Access Network (RAN). The multicast group IP address is converted into a multicast group Media Access Control (MAC) address. Based on the multicast group MAC address, the UE is added to the multicast group. 3 CN 119968867 A Specification 1' / 8 pages 5G LAN Ethernet Multicast Group Management and Traffic Forwarding Method Technical Field

[0001] This invention relates to 5G Local Area Networks (LANs), and particularly to 5G LAN Ethernet multicast group management and traffic forwarding. More specifically, this invention relates to a method for adding terminals such as UEs to multicast groups in a 5G LAN, releasing or removing UEs from multicast groups, and / or forwarding multicast data packets to UEs in multicast groups. Background Art

[0002] 5G LAN is a virtual local area network (VLAN) service built within a 5G network. It allows the creation of a mobile LAN to meet needs such as production or office work. In a 5G network, administrators can modify data in the user database and contract services to designated user equipment (UE) numbers, thus combining them into a 5G LAN. 5G LAN functionality provides industry users with wide-area mobile LAN and VPN service support, including Ethernet forwarding, broadcast / multicast, UE-to-UE communication, and group management.

[0003] 5G LANs support Ethernet traffic, and 5G networks can directly transmit Layer 2 protocols. The User Plane Function (UPF) should be able to identify the Media Access Control (MAC) address of the terminal and support the forwarding of Ethernet multicast traffic. The Layer 2 networking provided by 5G LANs enables industrial users to achieve efficient communication and isolation between devices, meeting the special requirements of industrial communication and improving the level of intelligence and automation in industrial production. Multicast is widely used in industrial scenarios because multicast / broadcast can achieve distributed control and management, thereby improving production efficiency and quality. 5G LANs support multicast, which can achieve more efficient and reliable production line control and management.

[0004] Vertical industries have very low latency requirements for Ethernet multicast forwarding. Without efficient 5G LAN multicast functionality, 5G systems cannot operate well in latency-sensitive 5G private networks, especially in 5G factories. 3GPP specifications and existing solutions do not provide an effective implementation method for 5G LAN multicast group management and forwarding. Therefore, among other things, a new method is needed to efficiently forward multicast traffic and manage multicast groups in 5G LANs.

[0005] The purpose of this invention is to mitigate or eliminate, to a certain extent, one or more problems associated with known methods for effectively forwarding multicast traffic and managing multicast groups in 5G local area networks.

[0006] The above-mentioned objective of this invention is achieved by a combination of the features of the main claims; the dependent claims discloseOther advantageous embodiments of the present invention.

[0007] Another object of the present invention is to provide a new method and system for adding a UE to a multicast group in a 5G local area network.

[0008] Another object of the present invention is to provide a new method and system for leaving a UE in a multicast group in a 5G local area network.

[0009] Another object of the present invention is to provide a new method for forwarding multicast data packets to a UE in a multicast group.

[0010] Other objects of the present invention will become apparent to those skilled in the art from the following description. Therefore, the above statement of objects is not exhaustive and is only used to illustrate a portion of the many objects of the present invention. Summary of the Invention

[0011] The present invention provides a system and method for managing 5G LAN Ethernet multicast groups and forwarding 5G data plane traffic, which is a key step in further supporting 5G networks for smart manufacturing, etc.

[0012] In a first principal aspect, the present invention provides a method for adding a UE to a multicast group in a 5G LAN. The method described in CN 119968867 A, page 2 / 8, includes the following steps performed by the UPF in the 5G core network: processing a multicast group join request message received from a UE in the 5G LAN to obtain a multicast group IP address; converting the multicast group IP address to a multicast group MAC address; and joining the UE to the multicast group according to the multicast group MAC address.

[0013] In a second main aspect, the present invention provides a method for a UE to leave a 5G LAN multicast group, comprising: receiving a UE multicast group leave request message at a UPF; processing the multicast group leave request message to obtain a multicast group IP address; converting the multicast group IP address into a multicast group MAC address / multicast group identifier (ID); mapping the F-SEID and the UE MAC address to a multicast group ID in a 5G multicast hash table; if a mapping is found in the 5G multicast hash table, comparing the multicast group ID in the multicast hash table entry with the multicast group ID obtained from the preceding conversion step; if they are the same, i.e., a match, the UPF deletes the UE from the multicast group UE list sharing the mapped multicast group MAC address / multicast group ID. Then, the UPF deletes the corresponding hash key of the deleted UE from the 5G multicast hash table.

[0014] In a third key aspect, the present invention provides a method for forwarding multicast data packets received from a UE in the 5G data plane of a 5G core network, the method comprising: receiving multicast data packets in a UPF in the 5G core network; the UPF being configured to process the multicast data packets to obtain the UE MAC address and UE F-SEID of the UE; the UPF being configured to use the UE MAC address and UE F-SEID to look up a 5G multicast hash table to find a group UE list of a relevant multicast group; and the UPF being configured to copy the multicast data packets and forward the multicast data packets to other UEs in the relevant multicast group.

[0015] In a fourth principal aspect, the present invention provides a network node in a 5G core network configured to perform a UPF of the 5G core network and configured to implement any of the methods of the first to third principal aspects of the present invention.

[0016] In a fifth principal aspect, the present invention provides a non-transitory computer-readable medium storing machine-readable instructions, wherein, when executed by a processor, the machine-readable instructions configure the processor to implement any of the methods of the first to third principal aspects of the present invention.

[0017] The abstract of the present invention does not necessarily disclose all the features necessary to define the present invention; the invention may exist in sub-combinations of the disclosed features.

[0018] The features of the invention have been summarized rather broadly above in order to better understand the following detailed description of the invention. Other features and advantages of the invention will be described below, which form the subject matter of the claims of the invention. Those skilled in the art will recognize that the disclosed concepts and specific embodiments can be readily used as the basis for modifications or the design of other structures for achieving the same purpose as the invention.

[0019] The foregoing and other features of the present invention will be apparent from the following description of preferred embodiments, which are provided by way of example only in conjunction with the accompanying drawings, in which:

[0020] FIG1 shows a known 3GPP 5G Service-Based Standalone Architecture (SBA);

[0021] FIG2 shows a 5G LAN, including virtual LAN services provided on a 5G network;

[0022] FIG3 shows problems encountered when implementing 5G LAN multicast forwarding and 5G LAN multicast management;

[0023] FIG4 is a flowchart of the method of adding a terminal (UE) to a multicast group in a 5G LAN according to the present invention;

[0024] FIG5 shows the structure of the 5G multicast hash table for adding a UE to a multicast group in a 5G LAN according to the present invention;

[0025] FIG6 shows the 5G multicast hash table for leaving a multicast group in a 5G LAN according to the present invention;

[0026] FIG7 shows multicast packet forwarding in a 5G LAN according to the present invention;

[0027] FIG8 shows the multicast packet forwarding method in a 5G LAN according to the present invention and the corresponding 5G multicast hash table;

[0028] Figure 9 is a flowchart of the multicast data packet forwarding method in 5G LAN of the present invention. 5 CN 119968867 A Specification "8 pages Detailed Description

[0029] The following description is only by way of example to describe preferred embodiments and does not limit the combination of necessary features for carrying out the present invention.

[0030] The phrase "an embodiment" or "an embodiment" mentioned in this specification means that a particular feature, structure or characteristic related to that embodiment is included in at least one embodiment of the present invention. The phrase "in an embodiment" appearing throughout the specification"In" does not necessarily refer to the same embodiment, nor is it a single or alternative embodiment that is mutually exclusive with other embodiments. Furthermore, the various features described may be shown by some embodiments but not by others. Similarly, various requirements are described, which may be requirements of some embodiments but not others.

[0031] It should be understood that the elements shown in the figures can be implemented in various forms of hardware, software, or combinations thereof. These elements can be implemented in a combination of hardware and software on one or more suitably programmed general-purpose devices, which may include processors, memory, and input / output interfaces.

[0032] This specification illustrates the principles of the invention. Therefore, it should be understood that those skilled in the art will be able to devise various arrangements, although not explicitly described or shown herein, that embody the principles of the invention and are included within its spirit and scope.

[0033] Furthermore, the principles, aspects, and embodiments of the invention, and specific examples thereof, are described herein to cover their structural and functional equivalents. Moreover, such equivalents also include currently known equivalents as well as those developed in the future, i.e., any developed elements that perform the same function, regardless of their structure.

[0034] Therefore, for example, those skilled in the art will understand that the block diagrams presented herein represent conceptual diagrams of systems and devices embodying the principles of the invention.

[0035] The functionality of the various elements shown in the figures can be provided by using dedicated hardware and hardware capable of executing software together with appropriate software. When provided by a processor, these functions can be provided by a single dedicated processor, a single shared processor, or multiple separate processors, some of which may be shared. Furthermore, the explicit use of the terms “processor” or “controller” should not be construed as referring only to hardware capable of executing software, and may implicitly include, but is not limited to, digital signal processor (“DSP”) hardware, read-only memory (“ROM”), random access memory (“RAM”), and non-volatile memory for storing software.

[0036] In the claims, any element represented as a means of performing a particular function is intended to cover any manner in which that function is performed, including, for example, a) a combination of circuit elements performing that function or b) any form of software, thus including firmware, microcode, etc., combined with appropriate circuitry to perform the function. The invention as defined by these claims is that the functionality provided by the various mentioned means is combined and brought together in the manner claimed in the claims. Therefore, any means of providing these functions is considered equivalent to the means shown herein.

[0037] The following description illustrates the implementation of the invention in a 5G communication network by way of example, but does not limit the implementation of the invention in suitable communication networks.

[0038] 5G LAN is a dedicated cellular network typically provided to enterprises and can be integrated into an organization's existing infrastructure. ItThey provide high-speed wireless access and deterministic performance for mission-critical applications. For example, 5G LAN can reduce the use of Ethernet cables. 5G LAN uses 5G terminal access capabilities and dedicated mobile LAN services to provide flexible communication services for group member terminals. 5G terminals, also known as 5G client devices (CPEs), enable devices such as computers, laptops, and mobile phones to connect to the Internet. 5G CPE devices receive 5G signals from base stations and then convert them into Wi-Fi or wired signals.

[0039] The terms “UE” and “CPE” mentioned herein should be understood as “terminal”, and vice versa.

[0040] Referring to the accompanying drawings, Figure 1 shows a known 3GPP 5G standalone service-based architecture (SBA), including known interfaces between 5G network nodes and / or functional elements.

[0041] Figure 2 shows a 5G network 10, which includes one or more virtual network (VN) groups in a 5G LAN 12. Each VN group includes a virtual LAN service configured on the 5G network 10. In Figure 2, UE1 to UE3 constitute the first VN group 12A, and UE4 to UE6 constitute the second VN group 12B. The first and second VN groups 12A and 12B are wirelessly connected to the core network 14 of the 5G network 10 via a radio access network (RAN) 16 including one or more base stations 18. The core network 14 may be connected to one or more data centers or data networks (DNs) 20. The core network 10 includes functional entities, including a UPF 22, a session management function (SMF) 24, and a unified data management (UDM) function 26. The functional entities may be implemented in core network nodes (e.g., servers), which are configured to perform their respective functions by executing machine-readable instructions stored on one or more non-transitory computer-readable media by one or more processors.

[0042] Figure 3 illustrates an example embodiment of an enterprise-based 5G LAN used to manage and / or control industrial machines (e.g., programmable logic controllers (PLCs)), and / or processes that cause problems when implementing 5G LAN multicast forwarding and 5G LAN multicast management.

[0043] Vertical industries have very low latency requirements for Ethernet multicast forwarding. Without efficient 5G LAN multicast capabilities, 5G systems cannot function well in low-latency-sensitive 5G private networks, especially in 5G factories. 3GPP specifications and existing solutions do not provide an efficient implementation method for 5G LAN multicast group management and forwarding.

[0044] The problem to be solved by the present invention is to implement a new method for efficiently forwarding multicast traffic and managing multicast groups in 5G LAN, and to achieve efficient 5G LAN multicast group management, which will be described below. Key embodiments of the present invention that solve these problems include a new method for UE to join a 5G LAN multicast group, a new method for UE to leave a 5G LAN multicast group, and a new method for multicast traffic forwarding.

[0045] The new method for joining a UE to a 5G LAN multicast group includes: UPF 22 processing a multicast group join request message received from a UE in the 5G LAN to obtain the multicast group Internet Protocol (IP) address, converting the multicast group IP address to a multicast group MAC address, and joining the UE to the multicast group according to the multicast group MAC address.

[0046] When the 5G core network 14 and 5G RAN 16 are correctly set up and ready, the UE (UE1 in Figures 2, 4 and 5) accesses the 5G RAN 16 and establishes an Ethernet Protocol Data Unit (PDU) session for the UE in UPF 22. If the UE wishes to join a multicast group, it will send a multicast group join request message. As shown in Figure 2, the multicast group join request message received by the UPF 22 from the UE includes an Internet Group Management Protocol (IGMP) join request message, which is carried by the GPRS Tunneling Protocol for User Plane (GTP-U) payload and includes a GTP-U header, a User Data Plane (UDP) header, and an IP header. The IGMP header is followed by the Ethernet header, which is transmitted to UPF 22 via the GTP-U tunnel. UPF 22 receives the IGMP group join request and, in response, adds an entry for the UE in the 5G multicast hash table, thereby adding the UE to the requested multicast group.

[0047] Figure 4 illustrates the steps of the new method 3 for adding the UE to the requested multicast group in more detail.

[0048] In the first step 31 of method 30, UPF 22 receives the IGMP group join request message from the UE. In the next step 32 of method 30, UPF 22 decodes the UE's Forwarding Tunnel Endpoint Identifier (F-TEID) in the GTP-U header and finds the UPF Fully Qualified Session Endpoint Identifier (F_SEID). In the next step 33 of method 30, UPF 22 decodes the UE's MAC address (UE1 in this example).(MAC address). Then, in the next step 34, UPF 22 decodes the IGMP header to obtain the multicast group IP address. In the subsequent step 35, UPF 22 converts the multicast group IP address to the multicast group MAC address and sets it as the multicast group identifier (ID). In the next step 36, based on the multicast group MAC address / multicast group ID, UPF 22 adds the UE (UE 1) to the multicast group UE list. Then, in the last step 37 of method 30, UPF 22 adds the hash key and value to the 5G multicast hash table.

[0049] Figure 5 shows the structure of the 5G multicast hash table for adding a UE to a 5G LAN multicast group. The hash key is a combination of the UE MAC address and the UPF F-SEID. Its value includes the multicast group ID / group UE list.

[0050] The step of converting the multicast group IP address to the multicast group MAC address and setting it as the multicast group ID preferably includes the following sub-steps. The first sub-step involves converting the multicast group IP address into a binary bit string. For example, when the multicast group IP address includes the address 239.0.1.1, the binary bit string is 11101111.00000000.00000001.00000001. The next sub-step involves extracting the last 23 bits, which is the underscore bit shown here as 11101111.00000000.00000001.000. Then, in the next sub-step, the last 23 binary bits are appended to a binary string that includes a fixed bit of the known MAC address prefix reserved for multicast. The fixed bits reserved for the MAC address prefix for multicast are 25 binary bits: 00000001.00000000.01011110.0o. Therefore, the resulting binary bit string is 00000001.000 00000.01011110.00000000.00000001.00000001. In the next sub-step, the resulting binary bit string is converted to hexadecimal to provide the multicast group MAC address, which is used when sending multicast traffic packets to UEs in the group's UE list. In this example, the hexadecimal form of the multicast group MAC address is HEX: 0x0100.5E00.0101, as shown in Figure 5. This is the MAC address used when sending information to group 239.0.1.1, and it is also the multicast group ID in the 5G multicast hash table.

[0051] The new method for a UE to leave a 5G LAN multicast group includes: receiving a UE multicast group leave request message at UPF 22, processing the multicast group leave request message to obtain the multicast group IP address, converting the multicast group IP address to a multicast group MAC address / multicast group ID, and using the F-SEID and UE...The MAC address is mapped to the multicast group ID in the 5G multicast hash table. If a mapping is found in the 5G multicast hash table, the multicast group ID in the multicast hash table entry is compared with the multicast group ID obtained from the previous conversion step. If they are the same, the UPF 22 removes the UE from the multicast group UE list that shares the mapped multicast group MAC address / multicast group ID. Then, the UPF 22 removes the corresponding hash key of the deleted UE from the 5G multicast hash table.

[0052] As shown in FIG2, the structure of the multicast group leave request message received by the UPF 22 from the UE is the same as that of the multicast group join request message.

[0053] More specifically, the method for the UE to leave the multicast group includes the following steps. In the first step, if the UE (e.g., UE1) wishes to leave the multicast group, the UE sends an IGMP leave group request message to the UPF 22, which carries an IGMP header and an IP / Ethernet header and is transmitted through a GTP-U tunnel. In the next step, the UPF 22 decodes the F-TEID in the GTP-U header and finds the UPF F-SEID. In the next step, UPF 22 decodes the Ethernet header to obtain the UE MAC address. Then, in the next step, UPF 22 decodes the IGMP header to obtain the multicast group IP address, then converts the multicast group IP address to a multicast group MAC address and derives the multicast group ID from it. In the next step, UPF 22 uses the UPF F-SEID and the UE MAC address as hash keys to map to the multicast group ID in the 5G multicast hash table to check if the multicast group ID from the previous step is the same as the multicast group ID in the 5G multicast hash table. If the mapped multicast group IDs are the same, UPF 22 removes the UE (UE1) entry from the group UE list of the corresponding multicast group, and then removes the corresponding hash key entry from the 5G multicast hash table, as shown in Figure 6.

[0054] As shown in Figure 7, the new method for multicast traffic forwarding includes: after receiving a multicast data packet from a UE on the 5G data plane of the 5G core network, the UPF 22 uses the UE MAC address and UE F-SEID as hash keys to map to the multicast group ID in the 5G multicast hash table. If the hash key maps to the multicast group ID, the UPF 22 copies the multicast data packet and forwards the multicast data packet to other UEs in the multicast group UE list that share the mapped multicast group ID. The UPF 22 obtains the UE MAC address and UE F-SEID from the multicast data packet received from the UE on the 5G data plane.

[0055] Figure 8 shows an embodiment of the multicast traffic forwarding method and the corresponding 5G multicast hash table. Figure 9 is a flowchart of a more detailed version of the method 40 shown on pages 6 / 8 of the specification of Figure 8 (CN 119968867 A).

[0056] In the first step 41 of method 40 in Figure 9, the UPF 22 receives a multicast Ethernet data packet from, for example, UE1 and decodes it.The UPF obtains the F-SEID from the GTP-U header, and then UPF 22 decodes the UE (UE1) MAC address. In the next optional step 42, the UPF performs a Packet Detection Rule (PDR) check to see if the UE belongs to the 5G LAN. If not, the method terminates. If so, in the next step 43, UPF 22 uses the UE MAC address and UPF F-SEID as hash keys to map to the 5G multicast hash table and obtain the multicast group ID. In the next step 44, the UPF checks if the obtained multicast group ID is the same as the multicast packet destination of the MAC address. If they are different, the method terminates. However, if they are the same, in the next step 45, UPF 22 copies the multicast Ethernet packet and forwards it to the UE in the same multicast group UE list or any UE, such as UE2 and UE3 in the examples of Figures 7 and 8.

[0057] This invention provides an apparatus and method for 5G LAN Ethernet multicast group management and traffic forwarding on the 5G data plane. The method for joining a 5G LAN multicast group includes: receiving 5G LAN user configuration configured by UDM on the SMF; establishing an uplink Ethernet PDU session for the UE on the UPF; accessing the 5G LAN network using the Ethernet PDU session from the UE; decoding the IGMP message when receiving an IGMP multicast group join request from the UE; and adding an entry to the 5G multicast group hash table on the UPF.

[0058] The UDM or Unified Data Repository (UDR) can store key 5G LAN user data, including VN group ID, data network name (DNN), Single Network Slice Selection Assistance Information (SNSSAI), and group members, etc.

[0059] The SMF can use the HTTP / 2 protocol to request 5G LAN user data from the UDM on the N10 interface.

[0060] The SMF can send an Ethernet PDN type session establishment request to the UPF on the N4 interface via the Packet Forwarding Control Protocol (PFCP), and then the UPF can establish an Ethernet PDU session for the 5G LAN UE.

[0061] Preferably, the UPF receives an IGMP input request encapsulated in GTP-U from the UE on the N3 interface on the established Ethernet PDU session, and then decodes the GTP-U encapsulation to find the F-TEID in the GTP-U header.

[0062] Preferably, the UPF further decodes the UE MAC address in the Ethernet header of the GTP-U payload and the multicast group IM address in the IGMP header.

[0063] The UPF can use the F-TEID to look up the PFCP session.

[0064] Preferably, the UPF decodes the multicast group IP from the IGMP header of the decapsulated GTP-U packet into a multicast group ID for 5G LAN group management.

[0065] The UPF can first convert the multicast group IP address into binary, take the last 23 bits and add them to the 25 bits of the known multicast MAC prefix, and then convert it to hexadecimal to obtain the multicast group ID.

[0066] The UPF adds a new entry to the 5G multicast hash table, where the hash table key is a combination of the UE MAC address and the UPF F-SEID, and the hash table entry is the multicast group ID and the group UE list.

[0067] This invention provides an apparatus and method for 5G LAN Ethernet multicast group management and traffic forwarding on a 5G data plane. The apparatus is configured to implement a method for leaving a 5G LAN multicast group, including: connecting to a 5G LAN network via an Ethernet PDU session on a UE; when receiving an IGMP multicast group leave request sent by the UE, the UPF decodes the IGMP message and then deletes the entry in the 5G multicast group hash table on the UPF.

[0068] The UPF can receive a GTP-U encapsulated IGMP leave request from the UE on an established Ethernet PDU session from the N3 interface, then decode the GTP-U encapsulation and find the F-TEID in the GTP-U header.

[0069] The UPF can further decode the UE MAC address in the Ethernet header of the GTP-U payload and the multicast group IP address in the IGMP header.

[0070] Preferably, the UPF uses the F-TEID to look up the UPF F-SEID.

[0071] Preferably, the UPF decodes the multicast group IP address from the IGMP header of the decapsulated GTP-U data packet and converts it into a multicast group ID for 5G LAN group management.

[0072] Preferably, the UPF first converts the multicast group IP into binary bits, takes the last 23 bits and adds them to the 25 bits of the known multicast MAC prefix, and then converts the resulting bit string into hexadecimal to obtain the multicast group ID.

[0073] The UPF uses the UPF F-SEID and the UE MAC address to look up an entry in the 5G multicast hash table and compares the multicast group ID in the entry with the multicast group ID in the previous segment.

[0074] If the multicast group ID matches, the UPF removes the UE from the group UE list in the 5G multicast hash table entry.

[0075] This invention provides a device for 5G LAN Ethernet multicast group management and traffic forwarding on the 5G data plane.The method supports multiple UPF deployments and allows multicast group traffic to be transmitted within a single UPF. The traffic forwarding method includes: accessing the 5G LAN network via an Ethernet PDU session on the UE; upon receiving a multicast data packet from the UE, the UPF decodes the GTP-U message; the UPF looks up the group UE list in the 5G multicast hash table; the UPF copies the multicast group traffic packet; and the UPF forwards the multicast group traffic packet to other UEs in the same group UE list.

[0076] Preferably, the UPF receives GTP-U encapsulated multicast data packets from the UE via the N3 interface on an established Ethernet PDU session, then decodes the GTP-U encapsulation and finds the F-TEID in the GTP-U header.

[0077] Preferably, the UPF uses the F-TEID to look up the UPF F-SEID.

[0078] Preferably, the UPF decodes the UE MAC address in the Ethernet header of the GTP-U payload and the multicast group IP address in the IGMP header.

[0079] Preferably, the UPF uses the UPF F-SEID and UE MAC address to look up entries in the 5G multicast hash table and find the group UE list in the 5G multicast hash table.

[0080] The UPF replicates multicast traffic for all other UEs in the same multicast group.

[0081] Preferably, the data structure of the 5G multicast hash table includes a hash key consisting of the UE MAC and UPF F-SEID, and a value consisting of the multicast group ID and the group UE list belonging to the same multicast group.

[0082] The present invention also provides a non-transitory computer-readable medium storing machine-readable instructions, wherein, when a processor executes the machine-readable instructions, they configure the processor to implement the method of any one of the appended method claims.

[0083] The above-described apparatus can be implemented at least partially in software. Those skilled in the art will understand that the above-described apparatus can be implemented at least partially using general-purpose computer equipment or using custom equipment.

[0084] Hereinafter, various aspects of the methods and apparatus described and described herein can be executed on any device, including communication systems. The programmatic aspects of this technology can be considered "products" or "articles of art," typically carried or embodied in a machine-readable medium in the form of executable code and / or associated data. "Storage" media include any or all memory, or related modules thereof, of mobile stations, computers, processors, or similar devices, such as various semiconductor memories, tape drives, disk drives, etc., which can provide storage for software programming at any time. All or part of the software can sometimes be communicated via the Internet or various other telecommunications networks. For example, such communication can enable the loading of software from one computer or processor to another. Therefore, another type of media that can carry software elements includes light waves, radio waves, and electromagnetic waves, for example, at physical interfaces between local devices, via wired and optical landline networks, and via various air links.use. Physical elements carrying such waves, such as wired or wireless links, optical links, etc., may also be considered as media carrying software. As used herein, unless limited to a tangible non-transitory "storage" medium, terms such as computer or machine "readable medium" refer to any medium that participates in providing instructions to a processor for execution. 10 •CN 119968867 A Description Page 8 / 8

[0085] Although the present invention has been illustrated and described in detail in the accompanying drawings and the foregoing description, it is to be regarded as illustrative rather than restrictive. It should be understood that only exemplary embodiments are shown and described, and the scope of the present invention is not limited in any way. It is to be understood that any feature described herein may be used in any embodiment. The illustrative embodiments do not exclude each other or other embodiments not mentioned herein. Therefore, the present invention also provides embodiments including combinations of one or more of the above illustrative embodiments. Modifications and variations can be made to the present invention without departing from the spirit and scope of the present invention, therefore, only the limitations as set forth in the appended claims should be imposed.

[0086] In the appended claims and the foregoing description of the present invention, unless the context otherwise requires by explicit language or necessary implication, the word "comprise" or variations such as "include" is used in an inclusive sense, that is, to specify the presence of the stated features, but not to exclude the presence or addition of further features in various embodiments of the present invention.

[0087] It should be understood that where any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms part of the common general knowledge in the art. 11 CN 119968867 A Description Drawings Page 1 / 8 Figure 12 CN 119968867 A Description Drawings Page 2 / 8 Source n l d l o Figure 沭 雎 0MI 9 eqs o n ■ ■ ■ ■ ■ I B A i W 1 O S § r a n s a a □ n l d l o sSv 、- M v q o s / — 画 p p 13 CN 119968867 A Description Drawings Page 3 / 8 Figure 3 14 Description Drawings Page 4 / 8 *CN 119968867 A 30 Figure 4 15 CN 119968867 A Description Drawings Page 5 / 8 Figure 5 Multicast data packet Destination MAC address Multicast group ID Group UE list 01:00:5e:00:01 UE1UE2 :01 UE3.. 01:00:5e:00:01 UE4UE5 :02 UE6.. Hash table key IIF1 MAC MdtiL UPFF SEID Figure 6 16 CN 119968867 A Description Drawings Page 6 / 8 □ UE3UE1 UE2 Figure 7 17 CN 119968867 ADescription of Drawings Page 778 Y Fan Yu Cai Duo Zhi Niao II 18 Description of Drawings Page 8 / 8• *CN 119968867 A 40 Figure 9 19

Claims

1. A method for adding a user equipment (UE) to a multicast group in a 5G local area network (LAN), the method comprising: At a network node configured to perform a user plane function (UPF) of a 5G core network, the following steps are performed: Processing a multicast group join request message received from the UE in the 5G LAN to obtain a multicast group Internet Protocol (IP) address; Converting the multicast group IP address to a multicast group media access control (MAC) address; The UE is added to the multicast group according to the multicast group MAC address.

2. The method according to claim 1, wherein the multicast group MAC address is set as a multicast group identifier (ID), and the UE is added to a multicast group UE list.

3. The method according to claim 2, wherein: A hash table key based on the MAC address of the UE is added to the 5G multicast hash table for the multicast group.

4. The method according to claim 3, wherein: The hash table key based on the MAC address of the UE is based on a combination of the UE MAC address and a fully qualified session endpoint identifier (F-SEID), wherein the F-SEID is obtained from a protocol data unit (PDU) session established by the UPF for the UE.

5. The method of claim 4, wherein a hash table entry including the multicast group ID and the multicast group UE list is added to a 5G multicast hash table of the multicast group.

6. The method according to claim 1, wherein the step of converting the multicast group IP address to the multicast group MAC address comprises: Converting the multicast group IP address into a binary bit string; selecting a predetermined number of binary bits in the second half of the bit string; appending the selected binary bits to a binary bit string comprising fixed bits of a MAC address prefix reserved for multicast; The obtained binary bit string is converted into hexadecimal to provide the multicast group MAC address, which is used when sending multicast traffic data packets to UEs in the group UE list of the multicast group.

7. The method of claim 6, wherein a predetermined number of binary bits selected from the second half of the binary bit string containing the multicast group IP address include the last 23 binary bits of the bit string, and the selected 23 binary bits are added to 25 binary bits containing fixed bits of a MAC address prefix reserved for multicast in the 5G LAN.

8. The method according to claim 5, wherein: After receiving a multicast data packet from the UE on the 5G data plane of the 5G core network, the UPF uses the UE MAC address and the UE F-SEID as hash keys to map to the multicast group ID in the 5G multicast hash table. If the hash key maps to a multicast group ID, the UPF copies the multicast data packet and forwards the multicast data packet to other UEs in the multicast group UE list that share the mapped multicast group ID.

9. The method according to claim 8, wherein the UPF obtains the UE MAC address and the UE F-SEID from the multicast data packet received from the UE on the 5G data plane.

10. The method according to claim 8, wherein: When the multicast data packet is received from the UE on the 5G data plane, the UPF determines whether the UE belongs to the 5G LAN, and if not, terminates the process.

11. The method according to claim 5, further comprising: receiving, at the UPF, a UE multicast group leave request message; Processing the multicast group leave request message to obtain the multicast group IP address; Convert the multicast group IP address to a multicast group MAC address / multicast group ID; Using the F-SEID and UE MAC address, mapped to the multicast group ID in the 5G multicast hash table, If a mapping is found in the 5G multicast hash table, the multicast group ID in the multicast hash table entry is compared with the multicast group ID obtained from the previous conversion step, If the multicast group ID in the multicast hash table entry matches the multicast group ID obtained from the previous conversion step, the UPF deletes the UE from the multicast group UE list that shares the mapped multicast group MAC address / multicast group ID.

12. The method of claim 11, wherein the UPF deletes the corresponding hash key of the deleted UE from the 5G multicast hash table.

13. A method for forwarding a multicast data packet received from a UE in a 5G data plane of a 5G core network, the method comprising: The UPF in the 5G core network receives the multicast data packet; The UPF is configured to process the multicast data packet to obtain a UE MAC address and a UE F-SEID of the UE; The UPF is configured to look up a 5G multicast hash table using the UE MAC address and the UE F-SEID to find a group UE list of a relevant multicast group; The UPF is configured to replicate the multicast data packet and forward the multicast data packet to other UEs in the relevant multicast group.

14. A network node in a 5G core network, the network node being configured to execute a user plane function (UPF) of the 5G core network and being configured to: Processing a multicast group join request message received from a UE located in a 5G LAN to obtain a multicast group Internet Protocol (IP) address, wherein the 5G LAN is connected to the 5G core network through a radio access network (RAN); Converting the multicast group IP address to a multicast group media access control (MAC) address; The UE is added to the multicast group according to the multicast group MAC address.

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