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DETECTION OF UPSTREAM DUPLICATED FRAMES IN LOW-POWER AND LOSSY NETWORKS

IP.com Disclosure Number: IPCOM000252451D
Publication Date: 2018-Jan-12
Document File: 4 page(s) / 148K

Publishing Venue

The IP.com Prior Art Database

Related People

Dechen Xu: AUTHOR [+4]

Abstract

An Internet Protocol version 6 (IPv6) extension header is used to remove the frame duplication caused by current Connected Grid (CG)-Mesh IEEE 802.15.4 packet retransmission. No additional protocol is required aside from adding the extension header in the IPv6 header. This provides a flexible and sensitive way to remove the duplicated frame based on different signal-to-noise ratio (SNR) environments. In other words, the duplicated frame packets may be removed if needed, thereby providing reliable packet transmission while saving bandwidth and improve the total data throughput.

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Copyright 2018 Cisco Systems, Inc. 1

DETECTION OF UPSTREAM DUPLICATED FRAMES IN LOW-POWER AND LOSSY NETWORKS

AUTHORS: Dechen Xu

Yuping Wang Zaochun Zhang Xiaopu Zhang

CISCO SYSTEMS, INC.

ABSTRACT

An Internet Protocol version 6 (IPv6) extension header is used to remove the frame

duplication caused by current Connected Grid (CG)-Mesh IEEE 802.15.4 packet

retransmission. No additional protocol is required aside from adding the extension header

in the IPv6 header. This provides a flexible and sensitive way to remove the duplicated

frame based on different signal-to-noise ratio (SNR) environments. In other words, the

duplicated frame packets may be removed if needed, thereby providing reliable packet

transmission while saving bandwidth and improve the total data throughput.

DETAILED DESCRIPTION

In existing Connected Grid (CG)-Mesh networks, the acknowledgment (ACK)

mechanism is used to ensure the unicast frame is received by the remote endpoint. Per the

ACK mechanism, on receiving a unicast frame, the receiver needs to send an ACK message

to the sender. If the sender fails to receive the ACK in a defined time, the sender will retry

to send the unicast frame. Generally, for a network in a good signal-to-noise ratio

(SNR)environment, this mechanism works well. However, in a poor SNR environment, the

ACK mechanism will prompt duplicated frames when the sender has multiple parents.

Figure 1 below illustrates an example upstream frame forwarding case.

Copyright 2018 Cisco Systems, Inc. 2

Figure 1

In this example, Node4 sends a unicast frame to its primary parent with good path

expected transmission count (ETX), and Node1 receives the frame and sends the ACK to

Node4. However, for a given reason, Node4 fails to receive the ACK from Node 1 after

several retries. Node4 then tries to send the same unicast frame to its backup parent Node2.

Therefore, duplicated frames are generated, and Node3 receives the frame twice (one from

Node1 and the other from Node2). Although the duplicated frame may be checked in an

upper layer (e.g., application layer), in a poor SNR environment, the issue of the duplicated

frames is very high and can consume too much bandwidth. For the low rate network,

duplicated frames degrade performance and bandwidth utilization.

Accordingly, a solution is presented herein that involves creating a dynamic table

to store the received frame’s information on the CG-Mesh node. The received frame’s

information may be unique for each frame in a short duration to enable the node to identify

whether a frame has already been received or forwarded. The source IPv6 address and a

unique tag or sequence may be used to identify each frame. The tag may be an option

carried in a hop-by-hop IPv6 extension header.

Copyright 2018 Cisco Systems, Inc. 3

An example method for detecting a duplicate frame is depicted in Figure 2 below.

Figure 2

First, Node4 generates a source IPv6 unicast packet. A unique tag or sequence is

created for this packet, and this unique...