# US 2020/0404458 A1 · Reliable link layer multicast in a low power wide area network > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0404458 A1 - Document ID: US20200404458A1 - Status: Published application - Kind: A1 - Application number: 17/010,749 - Filed: 2020-09-02 - Published: 2020-12-24 - Earliest claimed: 2018-02-22 - Assignees: Cisco Technology, Inc. - Applicants: Cisco Technology, Inc. - Inventors: PASCAL THUBERT; PATRICK WETTERWALD; PAUL B DUFFY; PATRICK GROSSETETE - Web page: https://patentgrep.com/patent/US20200404458A1 ## CPC - H04W 4/06: Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services - H04L 1/1685: {the supervisory signal being transmitted in response to a specific request, e.g. to a polling signal} - H04W 72/30: Resource management for broadcast services - H04W 74/0816: with collision avoidance - H04W 84/22: with access to wired networks - Y02D 30/70: in wireless communication networks - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE ## Abstract A management device for a low power wide area network can: generate and send, to each constrained wireless network device via a wired gateway, a link layer multicast listener command specifying a listening interval and causing each constrained wireless network device to change from a low-power optimized mode to a listening mode until reception of a multicast data packet within the listening interval; generate collision avoidance parameters including a minimum waiting interval, a maximum waiting interval relative to the listening interval, and a redundancy constant; and instruct the wired gateways to selectively transmit the multicast data packet based on the collision avoidance parameters, wherein each wired gateway responds by waiting a randomly-selected wait interval between the minimum and maximum waiting intervals, and selectively transmitting the multicast data packet only if a received number of the multicast data packet by the corresponding wired gateway is less than the redundancy constant. ## Claims ### Claim 1 A method comprising: receiving, by a constrained wireless network device in a low power wide area network, a link layer multicast listener command from an associated wired gateway via a link layer connection with the wired gateway, the link layer connection establishing an association by the constrained wireless network device with the wired gateway and providing a single-hop communications for the constrained wireless network device in the low power wide area network without requiring a routing protocol; changing, by the constrained wireless network device, from a low-power optimized mode to a listening mode in response to the link layer multicast listener command; maintaining, by the constrained wireless network device, the listening mode until one of reception of a multicast data packet from one of the associated wired gateway or a non-associated wired gateway in the low power wide area network, or detecting expiration of a listening interval specified in the link layer multicast listener command; and resuming, by the constrained wireless network device, the low-power optimized mode upon expiration of the listening mode. ### Claim 2 (depends on 1) The method of claim 1, wherein the resuming includes selectively repeating the changing for a second instance of the listening mode based on selectively receiving, during the first listening mode, an instruction specifying a next-listening interval for initiating the second instance of the listening mode. ### Claim 3 (depends on 1) The method of claim 1, wherein the receiving includes receiving the link layer multicast listener command during a prescribed listen window following transmission of a data frame by the constrained wireless network device. ### Claim 4 (depends on 1) The method of claim 1, further comprising the constrained wireless network device sending an acknowledgment in response to receiving the multicast data packet, the acknowledgment causing a management device, via the associated wired gateway, to maintain the constrained wireless network device within a multicast group associated with the multicast data packet. ### Claim 5 (depends on 1) The method of claim 1, wherein the low-power optimized mode is a sleep mode. ### Claim 6 (depends on 1) The method of claim 1, further comprising: repeating the changing for a corresponding instance of the listening mode until detecting a last multicast data packet among a sequence of multicast data packets; generating and unicast transmitting a bitmap based on determining an expiration of a corresponding listening interval of the last multicast data packet, the bitmap identifying received multicast data packets among the sequence of multicast data packets, the bitmap enabling identification of zero or more missing multicast data packets among the sequence of multicast data packets. ### Claim 7 (depends on 1) The method of claim 1, wherein the link layer multicast listener command is received as a unicast link layer transmission from the associated wired gateway. ### Claim 8 One or more non-transitory tangible media encoded with logic for execution by a machine and when executed by the machine operable for: receiving, by the machine implemented as a constrained wireless network device in a low power wide area network, a link layer multicast listener command from an associated wired gateway via a link layer connection with the wired gateway, the link layer connection establishing an association by the constrained wireless network device with the wired gateway and providing a single-hop communications for the constrained wireless network device in the low power wide area network without requiring a routing protocol; changing, by the constrained wireless network device, from a low-power optimized mode to a listening mode in response to the link layer multicast listener command; maintaining, by the constrained wireless network device, the listening mode until one of reception of a multicast data packet from one of the associated wired gateway or a non-associated wired gateway in the low power wide area network, or detecting expiration of a listening interval specified in the link layer multicast listener command; and resuming, by the constrained wireless network device, the low-power optimized mode upon expiration of the listening mode. ### Claim 9 (depends on 8) The one or more non-transitory tangible media of claim 8, wherein the resuming includes selectively repeating the changing for a second instance of the listening mode based on selectively receiving, during the first listening mode, an instruction specifying a next-listening interval for initiating the second instance of the listening mode. ### Claim 10 (depends on 8) The one or more non-transitory tangible media of claim 8, wherein the receiving includes receiving the link layer multicast listener command during a prescribed listen window following transmission of a data frame by the constrained wireless network device. ### Claim 11 (depends on 8) The one or more non-transitory tangible media of claim 8, further operable for sending an acknowledgment in response to receiving the multicast data packet, the acknowledgment causing a management device, via the associated wired gateway, to maintain the constrained wireless network device within a multicast group associated with the multicast data packet. ### Claim 12 (depends on 8) The one or more non-transitory tangible media of claim 8, wherein the low-power optimized mode is a sleep mode. ### Claim 13 (depends on 8) The one or more non-transitory tangible media of claim 8, further operable for: repeating the changing for a corresponding instance of the listening mode until detecting a last multicast data packet among a sequence of multicast data packets; generating and unicast transmitting a bitmap based on determining an expiration of a corresponding listening interval of the last multicast data packet, the bitmap identifying received multicast data packets among the sequence of multicast data packets, the bitmap enabling identification of zero or more missing multicast data packets among the sequence of multicast data packets. ### Claim 14 (depends on 8) The one or more non-transitory tangible media of claim 8, wherein the link layer multicast listener command is received as a unicast link layer transmission from the associated wired gateway. ### Claim 15 An apparatus implemented as a physical machine, the apparatus comprising: non-transitory machine readable media configured for storing executable machine readable code; a wireless device interface circuit configured for wirelessly receiving a link layer multicast listener command in a low power wide area network; and a processor circuit configured for executing the machine readable code, and when executing the machine readable code operable for: receiving, by the apparatus implemented as a constrained wireless network device in the low power wide area network, the link layer multicast listener command from an associated wired gateway via a link layer connection with the wired gateway, the link layer connection establishing an association by the constrained wireless network device with the wired gateway and providing a single-hop communications for the constrained wireless network device in the low power wide area network without requiring a routing protocol, changing from a low-power optimized mode to a listening mode in response to the link layer multicast listener command, maintaining the listening mode until one of reception of a multicast data packet from one of the associated wired gateway or a non-associated wired gateway in the low power wide area network, or detecting expiration of a listening interval specified in the link layer multicast listener command, and resuming the low-power optimized mode upon expiration of the listening mode. ### Claim 16 (depends on 15) The apparatus of claim 15, wherein the processor circuit is configured for selectively repeating the changing for a second instance of the listening mode based on selectively receiving, during the first listening mode, an instruction specifying a next-listening interval for initiating the second instance of the listening mode. ### Claim 17 (depends on 15) The apparatus of claim 15, wherein the receiving includes receiving the link layer multicast listener command during a prescribed listen window following transmission of a data frame by the constrained wireless network device. ### Claim 18 (depends on 15) The apparatus of claim 15, wherein the processor circuit is configured for sending an acknowledgment in response to receiving the multicast data packet, the acknowledgment causing a management device, via the associated wired gateway, to maintain the constrained wireless network device within a multicast group associated with the multicast data packet. ### Claim 19 (depends on 15) The apparatus of claim 15, wherein the low-power optimized mode is a sleep mode. ### Claim 20 (depends on 15) The apparatus of claim 15, wherein the processor circuit further is configured for: repeating the changing for a corresponding instance of the listening mode until detecting a last multicast data packet among a sequence of multicast data packets; generating and unicast transmitting a bitmap based on determining an expiration of a corresponding listening interval of the last multicast data packet, the bitmap identifying received multicast data packets among the sequence of multicast data packets, the bitmap enabling identification of zero or more missing multicast data packets among the sequence of multicast data packets.