# Competition: Controlled Replication for Higher Reliability and Predictability in Industrial IoT Networks

Hao Jiang, Zacharie Brodard, Tengfei Chang, Ahmed Bouabdallah, Nicolas Montavont, Géraldine Texier, Pascal Thubert, Thomas Watteyne, Georgios Papadopoulos

<figure><img src="image_1.png" /></figure>

## To cite this version:

Hao Jiang, Zacharie Brodard, Tengfei Chang, Ahmed Bouabdallah, Nicolas Montavont, et al. Competition: Controlled Replication for Higher Reliability and Predictability in Industrial IoT Networks. EWSN 2017: International Conference on Embedded Wireless Systems and Networks, Feb 2017, Uppsala, Sweden. hal-01664764

HAL Id: hal-01664764

https://inria.hal.science/hal-01664764v1

Submitted on 14 May 2025

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

<figure><img src="image_2.png" /></figure>

Distributed under a Creative Commons Attribution 4.0 International License
# Competition: Controlled Replication for Higher Reliability and Predictability in Industrial IoT Networks

Hao Jiang
Télécom Bretagne, France

Zacharie Brodard
Ecole Polytechnique, France

Tengfei Chang
EVA team, Inria, France

Ahmed Bouabdallah
Télécom Bretagne, France

Nicolas Montavont
Télécom Bretagne, France

Geraldine Texier
Télécom Bretagne, France

Pascal Thubert
Cisco Systems, France

Thomas Watteyne
EVA team, Inria, France

Georgios Z. Papadopoulos
Télécom Bretagne, France

## Abstract

Applications such as the smart grid or vehicle automa-
tion require deterministic transmissions with properties such
as on-time data deliveries and end-to-end reliability close to
100%. We introduce a novel mechanism based on BIER-
TE, a scheme in which parallel transmissions over several
paths are scheduled, while promiscuous listening between
the paths enables nodes to possibly overhear transmissions
on the other. We propose an implementation of this new ap-
proach for the dependability competition.

## Keywords

Multi-path Routing Algorithm, Path Diversity, BIER-TE

## 1 Introduction

In the context of the dependability competition, we pro-
pose a novel routing protocol which aims at providing de-
terministic networking over a lossy wireless medium. This
work is issued from the needs for the Industry 4.0, an emerg-
ing concept which consists in reusing the Internet of Things
(IoT) technologies to simplify the production chains, ease
the deployment and make the factory more flexible. In this
context, communications need to be deterministic.

Determinism in a network brings the guarantee that a par-
ticular information is transported across the network in a
tight window of time, and that a periodic process will be
repeated identically every time [3]. To this aim, a determin-
istic flow must traverse the network in the same predictable
fashion every time, regardless of the load of the network,
the link quality, and the network congestion. However, the

<figure><img src="image_3.png" /><figcaption>Figure 1: Packet replication and elimination.</figcaption></figure>

deployed IoT technologies are based on best-effort packet
switched network, where the data packets are subject to vari-
able delay in the network, due to retransmissions and en-
queuing in intermediate nodes.

In 2016, the IEEE 802.15.4-2015 standard [1] was pub-
lished to offer Quality of Service (QoS) for determinis-
tic industrial applications. Time-Slotted Channel Hopping
(TSCH) is among the Medium Access Control (MAC) pro-
tocols defined in this standard, which combines Time Di-
vision Multiplexing (TDM) with channel agility in order to
defeat interference. However, it does not avoid retransmis-
sions, since links are subject to losses, so wireless transmis-
sions are typically associated with a retry mechanism, such
as Automatic Repeat-reQuest (ARQ). Retransmission comes
at a cost in terms of delay (in best-effort traffic), energy con-
sumption and bandwidth, since it requires additional time
slots. Typically, if a transmission of a data packet fails, the
sending node may need to wait for the next slotframe to retry.
If the transmission of a data packet failed after several retries,
the routing protocol (RPL in our case) uses fail-over mech-
anism, but the delay in discovering and using an alternative
path is often very long.
<figure><img src="image_4.png" /><figcaption>Figure 2: Bird view of the testbed deployed at Cisco PIRL.</figcaption></figure>

We propose to enhance the forwarding mechanism in RPL-based network to duplicate the data flow on an alternate path. This allows anticipating potential link errors on a single path and exploiting path diversity in a dense network. We show that determinism can be guaranteed by using multiple parallel data paths, and thus provide high delivery rate and a very low jitter.

## 2 BIER-TE: Toward Multipath Redundancy

We propose to extend Bit Index Explicit Replication with Traffic Engineering (BIER-TE) mechanism defined at the IETF [2]. The BIER header contains a bitmap in which each bit represents exactly one egress router in the domain. To send a packet to a particular set of egress nodes, the ingress node sets the bits for each of those egress nodes, and clears other bits in the bitmap.

BIER-TE uses explicit hop-by-hop forwarding and loose hop forwarding of packets. The source of a data packet (which can also be the ingress router) inserts a bitmap in the packet header to inform nodes whether to forward, eliminate or replicate packets. Each bit of the bitmap represents an adjacency between two nodes. BIER-TE thus relies on a BIER-TE controller which learns the network topology, computes paths, and assigns a bit index to each adjacency. Moreover, it installs in each of the nodes a Bit Index Forwarding Table (BIFT), indicating how to forward a packet according to the packets bitmap. On the destination node, the bitmap present in the packet when it reaches the destination is inspected by the controller which identifies transmission failures and learns the link conditions. The controller accordingly modifies the bitmap for next packets, thereby dynamically controlling the replication and elimination activities according to the QoS requirements. In the implementation that we will propose for this competition, we will determine how packets can be duplicated in the network in order to reach 100% delivery ratio, and a jitter close to 0 by minimizing (or even avoiding) retransmissions.

## 3 Performance Evaluation

A set of experiments were conducted to evaluate BIER-TE using the testbed shown in Fig. 2, with an IEEE802.15.4-2015 TSCH LLN composed of 8 OpenMotes running OpenWSN<fnref n="1" /> firmware in the data plane and a controller in the control plane. The motes are distributed on the sixth floor

<figure><img src="image_5.png" /><figcaption>Figure 3: Performance of BIER-TE, when compared with retry-based single path. Delay of -1 means a packet loss.</figcaption></figure>

at Cisco PIRL with a topology in a general shape of a ladder. In order to compare the results to the situation without BIER-TE, the source node 9E-D9 is configured to transmit 3 packets every 2.5 s. Two single-path packets take the lower and upper path, respectively, with limited retries at each hop. One multi-path packet takes a complex path with packet replication and elimination enabled by BIER-TE.

Fig. 3 shows the results of the experiment:

Retransmissions have a straightforward impact on jitter. The more retransmissions at the MAC layer, the higher the jitter. On the contrary, BIER-TE presents zero jitter and stable performance throughout the experimental lifetime.

Packet replication along alternative paths effectively overcomes link or node failure, which increases reliability and reduces burst packet losses. Retransmissions are less immune to burst losses, and if a transmission failed, using retries has greater chance to fail again.

## 4 Conclusion

Issued from the Industry 4.0 needs, the IoT technology is moving toward deterministic wireless networks. We propose a new mechanism with replication to transport data packets in a predefined and constant delay. We expect attendees to experience the functionality and consequently the gain of BIER-TE under harsh environmental conditions.

## 5 References

[1] IEEE Standard for Low-Rate Wireless Personal Area Networks (LR-WPANs). IEEE Std 802.15.4-2015 (Revision of IEEE Std 802.15.4-2011), April 2016.

[2] T. Eckert, G. Cauchie, W. Braun, and M. Menth. Traffic engineering for bit index explicit replication. Internet-Draft draft-eckert-bier-te-arch-04, IETF Secretariat, September 2016. https://tools.ietf.org/id/draft-eckert-bier-te-arch-04.txt.

[3] T. Matsui, G. Z. Papadopoulos, P. Thubert, T. Watteyne, and N. Montavont. Poster: 4th Industrial Revolution: Toward Deterministic Wireless Industrial Networks. In Proceedings of the International Conference on Embedded Wireless Systems and Networks (EWSN), 2017.

<footnote n="1">¹ www.openwsn.com</footnote>