# US 11,909,545 B2 · Localized multicast in a low power and lossy network based on rank-based distance

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- Number: US 11,909,545 B2
- Document ID: US11909545B2
- Status: Granted
- Kind: B2
- Application number: 17/866,768
- Filed: 2022-07-18
- Published: 2022-11-03
- Granted: 2024-02-20
- Earliest claimed: 2020-02-13
- Assignees: Cisco Technology, Inc.
- Applicants: Cisco Technology, Inc.
- Inventors: Pascal Thubert; Huimin She; Chuanwei Li; Lele Zhang
- Web page: https://patentgrep.com/patent/US11909545B2

## CPC

- H04L 12/1845: {broadcast or multicast in a specific location, e.g. geocast (protocols for adapting network applications to user terminal location H04L67/52; services specially adapted for wireless communication networks making use of the location of users or terminals H04W4/02)}
- H04L 1/08: by repeating transmission, e.g. Verdan system {(H04L1/1858 and H04L1/189 take precedence)}
- H04L 12/189: {in combination with wireless systems (selective distribution or broadcast in wireless communication networks H04W4/06)}
- H04L 12/4633: {Interconnection of networks using encapsulation techniques, e.g. tunneling}
- H04L 45/16: Multipoint routing
- H04L 45/32: {Flooding (denial of service attacks H04L63/1458)}
- H04W 40/02: Communication route or path selection, e.g. power-based or shortest path routing
- H04W 40/023: {Limited or focused flooding to selected areas of a network}
- H04W 40/32: for defining a routing cluster membership
- H04L 12/185: {with management of multicast group membership}
- H04L 2001/0093: {Point-to-multipoint}
- Y02D 30/70: in wireless communication networks
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- 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

In one embodiment, a method comprises: identifying, by a low power and lossy network (LLN) device in a low power and lossy network, a minimum distance value and a distance limit value for limiting multicast propagation, initiated at the LLN device, of a multicast data message in the LLN; and multicast transmitting, by the LLN device, the multicast data message with a current distance field specifying the minimum distance value and a distance limit field specifying the distance limit value, the multicast transmitting causing a receiving LLN device having a corresponding rank in the LLN to respond to the multicast data message by: (1) determining an updated distance based on adding to the current distance field a rank difference between the receiving LLN device and the LLN device, and (2) selectively retransmitting the multicast data message if the updated distance is less than the distance limit value.

## Claims

### Claim 1

A method comprising:
receiving, by a receiving low power and lossy network (LLN) device in a low power and lossy network, one or more multicast data messages from respective one or more neighboring transmitting LLN devices in the LLN;
detecting, by the receiving LLN device among the one or more multicast data messages, a lowest distance value in a current distance field and a distance limit value in a distance limit field, the lowest distance value indicating a multicast transmission distance of a corresponding one neighboring transmitting LLN device relative to a multicast origin of the one or more multicast data messages;
determining, by the receiving LLN device, an updated distance to the multicast origin based on adding to the lowest distance value a rank difference between the corresponding neighboring transmitting LLN device and the receiving LLN device; and
selectively multicast transmitting, by the receiving LLN device, the multicast data message based on determining the updated distance is less than the distance limit value that limits multicast propagation, the selectively multicast transmitting including updating the current distance field with the updated distance prior to transmission,
wherein the selectively multicast transmitting includes suppressing any transmission of the multicast data message in response to determining the updated distance is not less than the distance limit value.

### Claim 2 (depends on 1)

The method of claim 1, further comprising:
detecting by the receiving LLN device, within the one multicast data message specifying the lowest distance value, a wireless transceiver tuning value associated with the one neighboring transmitting LLN device, and a multicast objective function identifier; and
determining, by the receiving LLN device, receiver metrics associated with reception of the one multicast data message specifying the lowest distance value;
the determining of the updated distance including determining a corresponding rank of the receiving LLN device as a multicast rank based on executing an objective function, identified by the multicast objective function identifier, relative to the wireless transceiver tuning value and the receiver metrics, and applying the multicast rank to the rank difference between the corresponding neighboring transmitting LLN device.

### Claim 3 (depends on 1)

The method of claim 1, further comprising:
detecting by the receiving LLN device, within the one multicast data message specifying the lowest distance value, a corresponding rank of the corresponding one neighboring transmitting LLN device in a current rank field, and a rank limit in a rank limit field;
selectively limiting one or more of upward flooding or downward flooding of the multicast data message in the LLN based on a corresponding rank of the receiving LLN device relative to the current rank field and the rank limit;
wherein the rank limit identifies one or more of a minimum rank limit for limiting upward flooding to an LLN device having the minimum rank limit as its corresponding rank, or a maximum rank limit for limiting downward flooding to an LLN device having the maximum rank limit as its corresponding rank.

### Claim 4

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 a machine implemented as a receiving low power and lossy network (LLN) device in a low power and lossy network, one or more multicast data messages from respective one or more neighboring transmitting LLN devices in the LLN;
detecting, by the receiving LLN device among the one or more multicast data messages, a lowest distance value in a current distance field and a distance limit value in a distance limit field, the lowest distance value indicating a multicast transmission distance of a corresponding one neighboring transmitting LLN device relative to a multicast origin of the one or more multicast data messages;
determining, by the receiving LLN device, an updated distance to the multicast origin based on adding to the lowest distance value a rank difference between the corresponding neighboring transmitting LLN device and the receiving LLN device; and
selectively multicast transmitting, by the receiving LLN device, the multicast data message based on determining the updated distance is less than the distance limit value that limits multicast propagation, the selectively multicast transmitting including updating the current distance field with the updated distance prior to transmission,
wherein the selectively multicast transmitting includes suppressing any transmission of the multicast data message in response to determining the updated distance is not less than the distance limit value.

### Claim 5 (depends on 4)

The one or more non-transitory tangible media of claim 4, further operable for:
detecting by the receiving LLN device, within the one multicast data message specifying the lowest distance value, a wireless transceiver tuning value associated with the one neighboring transmitting LLN device, and a multicast objective function identifier; and
determining, by the receiving LLN device, receiver metrics associated with reception of the one multicast data message specifying the lowest distance value;
the determining of the updated distance including determining a corresponding rank of the receiving LLN device as a multicast rank based on executing an objective function, identified by the multicast objective function identifier, relative to the wireless transceiver tuning value and the receiver metrics, and applying the multicast rank to the rank difference between the corresponding neighboring transmitting LLN device.

### Claim 6 (depends on 4)

The one or more non-transitory tangible media of claim 4, further operable for:
detecting by the receiving LLN device, within the one multicast data message specifying the lowest distance value, a corresponding rank of the corresponding one neighboring transmitting LLN device in a current rank field, and a rank limit in a rank limit field;
selectively limiting one or more of upward flooding or downward flooding of the multicast data message in the LLN based on a corresponding rank of the receiving LLN device relative to the current rank field and the rank limit;
wherein the rank limit identifies one or more of a minimum rank limit for limiting upward flooding to an LLN device having the minimum rank limit as its corresponding rank, or a maximum rank limit for limiting downward flooding to an LLN device having the maximum rank limit as its corresponding rank.