# A Tale of Many Networks: Splitting and Merging of Chord-like Overlays in Partitioned Networks
## 1 Introduction
* A new report [5] lists further cases in Gabon ([[https://pulse.internetsociety.org/shutdowns/internet-shutdowns-amidst-gabon-elections](https://pulse.internetsociety.org/shutdowns/internet-shutdowns-amidst-gabon-elections)]([https://pulse.internetsociety.org/shutdowns/internet-shutdowns-amidst-gabon-elections](https://pulse.internetsociety.org/shutdowns/internet-shutdowns-amidst-gabon-elections)), accessed on 26 May 2025) (27 August and 14 September 2016, and starting from 26 to 30 August 2023), coinciding with the closure of polling stations after an election. * In Iran, the Internet was shut down from 15 November to 24 November 2019 to \"suppress the widespread aban-e-khoonin\" movement. The report states that this was the most severe disconnection tracked by NetBlocks in terms of its technical complexity and scale ([[https://netblocks.org/reports/internet-disrupted-in-iran-amid-fuel-protests-in-multiple-cities-pA25L18b](https://netblocks.org/reports/internet-disrupted-in-iran-amid-fuel-protests-in-multiple-cities-pA25L18b)]([https://netblocks.org/reports/internet-disrupted-in-iran-amid-fuel-protests-in-multiple-cities-pA25L18b](https://netblocks.org/reports/internet-disrupted-in-iran-amid-fuel-protests-in-multiple-cities-pA25L18b)), accessed on 26 May 2025). In 2023, the initiative \"Women, Life, Freedom\" led to only a partial Internet shutdown. * In Cuba, similar events were observed on 11 July 2021 ([[https://www.yucabyte.org/2023/01/25/cloudflare-radar-cuba-internet/](https://www.yucabyte.org/2023/01/25/cloudflare-radar-cuba-internet/)]([https://www.yucabyte.org/2023/01/25/cloudflare-radar-cuba-internet/](https://www.yucabyte.org/2023/01/25/cloudflare-radar-cuba-internet/)), accessed on 26 May 2025) related to large protests against local COVID-19 regulations. * Earthquakes, such as in Taiwan in December 2006 ([[http://news.bbc.co.uk/2/hi/asia-pacific/6211451.stm](http://news.bbc.co.uk/2/hi/asia-pacific/6211451.stm)]([http://news.bbc.co.uk/2/hi/asia-pacific/6211451.stm](http://news.bbc.co.uk/2/hi/asia-pacific/6211451.stm)), accessed on 26 May 2025), might lead to Internet shutdowns due to link damages. * A Shurfshark report on ongoing Internet limitations ([[https://surfshark.com/research/internet-censorship](https://surfshark.com/research/internet-censorship)]([https://surfshark.com/research/internet-censorship](https://surfshark.com/research/internet-censorship)), accessed on 26 May 2025) shows that, in general, \"protests were the primary trigger for Internet shutdowns\", as [5] points out. A further useful tool to monitor ongoing shutdowns is listed by the Internet Society ([[https://pulse.internetsociety.org/shutdowns](https://pulse.internetsociety.org/shutdowns)]([https://pulse.internetsociety.org/shutdowns](https://pulse.internetsociety.org/shutdowns)), accessed on 26 May 2025). In cases where a network partitioning event occurs, participants of a disrupted peer-to-peer overlay should be capable of maintaining the network in corresponding geographical regions. The split of the overlay should survive, and the overlay network should quickly stabilize. In addition, and more challenging, once the connectivity of the underlying network is re-established, various overlays should detect their presence and merge into one global overlay again. To address this gap, we focus on the problem of merging ring-based structured overlays after a network partition. Our work is motivated by the need for resilient communication infrastructures in the face of technical failures, natural disasters, or political interventions. The contributions of the paper are as follows:  
* We elaborate on the problem of network partitioning in ring-based peer-to-peer overlay networks in Section 1.1 and discuss related work in Section 2.