For the viability of future "mission-critical" applications such as remote surgery and connected cars, the customers must trust the network connection and operators must adhere to the Service Level Agreement (SLA). The key to enabling trust between the customer and the operator is the transparency and accountability of the SLA. That is, the operators ensure the transparent and appropriate execution of SLA clauses (e.g., Quality of Service (QoS) and compensations if the SLA is violated). In this work, we argue that today's network is highly volatile. Therefore, it is convenient for the operators to provide service guarantees for short-term rather than traditional long-term methods. Consequently, we advocate short-term and dynamic service contracts considering spatial and temporal characteristics rather than typical long-term contracts. We propose a Distributed Ledger Technology (DLT)-focused end-to-end transparent, accountable and automated resource provisioning system architecture in which are installed as smart contracts. In our architecture, resources can be requested and allocated dynamically and automatically with Quality-of-Service (QoS) monitoring. Our architecture is scalable through a side-channel based QoS monitoring protocol that guarantees data integrity and minimises the Permissioned Distributed Ledgers (PDL) updates. To measure the viability of our proposal, we first evaluate resource provisioning in the context of network slicing. Then we assess the DLT performance for smart contract execution, in both permissioned and permission-less settings. In the end, we evaluate the monitoring tools and compare and contrast sketches and bloomfilters, and justify our choice of bloomfilters.

In the context of industrial environment, devices, such as robots and drones, are vulnerable to malicious activities such device tampering (e.g., hardware and software changes). The problem becomes even worse in a multi-stakeholder environment where multiple players contribute to an ecosystem. In such scenarios, particularly, when devices are deployed in remote settings, ensuring device integrity so that all stakeholders can trust them is challenging. Existing methods, often depend on additional hardware like the Trusted Platform Module (TPM) which may not be universally provided by all vendors. In this study, we introduce a distributed ledger technology-oriented architecture to monitor the remote devices' integrity using eUICC technology, a feature commonly found in industrial devices for cellular connectivity. We propose that using secure applets in eUICC, devices' integrity can be monitored and managed without installing any additional hardware. To this end, we present an end-to-end architecture to monitor device integrity thereby enabling all the stakeholders in the system to trust the devices. Additionally, we leverage the properties of immutable databases to provide robustness and efficiently to our model. In our primary evaluations, we measure the overhead caused by hashing our proposed data packets and performance of integrating an immutable database into our system. Our results show that performing hashing on our data packets takes order of microseconds, while reading and writing to an immutable database also requires only milliseconds.

Industrial Control Systems (ICS) have specific data requirements in terms of Quality of Service (QoS). Lost or delayed critical data, such as control signals, can damage widespread production, such as machine performance. The problem is compounded in the next-generation Industry 4.0, where the operations will be even less human-dependent, involving multiple organizations. Moreover, the communication aspects across multistakeholders require a disaggregated approach contrary to the current closed ICS architecture.This paper presents a framework for decentralization of ICS called Operations and Control Networks (OCN) in which ‘contracts’ are the basic units of abstraction to exchange information with trust and precision between different actors. In the lower layers, High-Precision Communication (HPC) contracts execute control functions with requested service level guarantees in the network. A high-level trusted delegation of tasks is executed as smart contracts using Distributed Ledger Technology (DLT) to enable multi-stakeholder auditability and accountability.

With the growing demand for network connectivity and diversity of network applications, one primary challenge that network service providers are facing is managing the commitments for Service Level Agreements (SLAs). Service providers typically monitor SLAs for management tasks such as improving their service quality, customer billing and future network planning. Network service customers, on their side, monitor services provided to them, to optimize their network usage and apply, when required, penalties related to service failures. In future 6G networks, critical network applications such as remote surgery and connected vehicles will require these SLAs to be more dynamic, flexible, and automated to match their diverse requirements on network services. Moreover, these SLAs should be transparent to all stakeholders to address the trustworthiness on network services and service providers required by critical applications. Currently, there is no standardized method to immutably record and audit SLAs, leading to challenges in aspects such as SLA enforcement and accountability - traits essential for future network applications. This work explores new requirements for future service contracts, that is, on the evolution of SLAs. Based on those new requirements, we propose an end to end layered SLA architecture leveraging Distributed Ledger Technology (DLT) and smart contracts. Our architecture is inheritable by an existing telco-application layered architectural frameworks to support future SLAs. We also discuss some limitations of DLT and smart contracts and provide several directions of future studies.

Security, privacy, and trust are the key factors to unlock the full potential of future communication as beyond 5G and 6G systems enable new and more disruptive business models involved with multiple stakeholders, including mobile network operators, mobile virtual network operators, infrastructure providers, third party service providers, policy makers, end-users, and etc. The huge set of data, interaction process, and service management across these stakeholders require new technologies that can help the telecom industry to manage various data related to users, interaction process, and services in a way that is immutable, transparent, and secure with reduced OPEX to stay ahead of the market and to meet the evolving horizontal and vertical service and security requirements. This article presents an overview of the more promising key enablers, such as blockchain, permissioned distributed ledger technologies, and smart contract that can tackle the challenges of data security, privacy, and trust management in various potential beyond 5G and 6G application scenarios.

Infrastructure sharing is a widely discussed and implemented approach and is successfully adopted in telecommunications networks today. In practice, it is implemented through prior negotiated service level agreements (SLAs) between the parties involved. However, it is recognized that these agreements are difficult to negotiate, monitor, and enforce. For future 6G networks, resource and infrastructure sharing is expected to play an even greater role. It will be a crucial technique for reducing over-all infrastructure costs and increasing operational efficiencies for operators. More efficient SLA mechanisms are thus crucial to the success of future networks. In this work, we present BEAT, an automated, transparent, and accountable end-to-end architecture for network sharing based on blockchain and smart contracts. This work focuses on a particular type of blockchain, permissioned distributed ledger, due to its permissioned nature allowing for industry-compliant SLAs with stringent governance. Our architecture can be implemented with minimal hardware changes and with minimal overheads.

It is widely expected that future networks of 6G and beyond will substantially improve on 5G. Technologies such as Internet of Skills and Industry 4.0 will become stable and viable, as a direct consequence of networks that offer sustained and reliable mobile performance levels. The primary challenges for future technologies are not just low-latency and high-bandwidth. The more critical problem Mobile Service Providers (MSPs) will face will be in balancing the inflated demands of network connections and customers’ trust in the network service, that is, being able to interconnect billions of unique devices while adhering to the agreed terms of Service Level Agreements (SLAs). To meet these targets, it is self-evident that MSPs cannot operate in a solitary environment. They must enable cooperation among themselves in a manner that ensures trust, both between themselves as well as with customers. In this study, we present the BEAT (Blockchain-Enabled Accountable and Transparent) Infrastructure Sharing architecture. BEAT exploits the inherent properties of permissioned type of distributed ledger technology (i.e., permissioned distributed ledgers) to deliver on accountability and transparency metrics whenever infrastructure needs to be shared between providers. We also propose a lightweight method that enables device-level accountability. BEAT has been designed to be deployable directly as only minor software upgrades to network devices such as routers. Our simulations on a resource-limited device show that BEAT adds only a few seconds of overhead processing time – with the latest state-of-the-art network devices, we can reasonably anticipate much lower overheads.

The specialness of New Year eve traffic is a telecoms industry fable. But how true is it, and what's the impact on user experience? We investigate this on the four UK cellular networks, in London, on New Year eve in 2016/17, 2017/18, 2018/19 and 2019/20 (covid cancelled 2020/21 & 2021/22). Overall, we captured 544,560 readings across 14 categories using 3G/4G/5G devices. This paper summarises our longitudinal readings into 10 observations on the nature of network performance, from a user's perspective, on special days such as New Year eve. Based on these, we confirm that mature 3G/4G networks are unable to deliver a consistent user experience, especially on atypical days. For example, on 4G, a user had a 60% chance to get a latency below 50 ms and 90% chance for 500ms. If repeated in mature 5G networks, it suggests that it is inadequate to support safety-critical 5G use cases.

The viability of new mission-critical networked applications such as connected cars or remote surgery is heavily dependent on the availability of truly customized network services at a Quality of Service (QoS) level that both the network operator and the customer can agree on. This is difficult to achieve in today’s mainly "best effort" Internet. Even if a level of service were to be agreed upon between a consumer and an operator, it is important for both parties to be able to scalably and impartially monitor the quality of service delivered in order to enforce the service level agreement (SLA). Building upon a recently proposed architecture for automated negotiation of SLAs using smart contracts, we develop a low overhead solution for monitoring these SLAs and arranging automated payments based on the smart contracts. Our solution uses cryptographically secure bloom filters to create succinct summaries of the data exchanged over fine-grained epochs. We then use a state channel-based design for both parties to quickly and scalably agree and sign off on the data that was delivered in each epoch, making it possible to monitor and enforce at run time the agreed upon QoS levels.

5G promises unprecedented levels of network connectivity to handle diverse applications, including life-critical applications such as remote surgery. However, to enable the adoption of such applications, it is important that customers trust the service quality provided. This can only be achieved through transparent Service Level Agreements (SLAs). Current resource provisioning systems are too general to handle such variety in applications. Moreover, service agreements are often opaque to customers, which can be an obstacle for 5G adoption for mission-critical services.In this work, we advocate short-term and specialised rather than long-term general service contracts and propose an end-to-end Permissioned Distributed Ledger (PDL) focused architecture; which allows operators to advertise their service contracts on a public portal backed by a PDL. These service contracts with clear Service Level Agreement (SLA) offers are deployed as smart contracts to enable transparent, automatic and immutable SLAs. To justify our choice of using a permissioned ledger instead of permissionless, we evaluated and compared contract execution times on both permissioned (i.e. Quorum and Hyperledger Fabric) and permissionless (i.e. Ropsten testnet) ledgers.

New applications such as remote surgery and connected cars, which are being touted as use cases for 5G and beyond, are mission-critical. As such, communications infrastructure needs to support and enforce stringent and guaranteed levels of service before such applications can take off. However, from an operator's perspective, it can be difficult to provide uniformly high levels of service over long durations or large regions. As network conditions change over time, or when a mobile end point goes to regions with poor coverage, it may be difficult for the operator to support previously agreed upon service agreements that are too stringent. Second, from a consumer's perspective, purchasing a stringent service level agreement with an operator can also be expensive. Finally, failures in mission critical applications can lead to disasters, so infrastructure should support assignment of liabilities when a guaranteed service level is reneged upon - this is a difficult problem because both the operator and the customer have an incentive to lay the blame on each other to avoid liabilities of poor service. To address the above problems, we propose AJIT, an architecture that allows creating fine-grained short-term contracts between operator and consumer. AJIT uses smart contracts to allow dynamically changing service levels so that more expensive and stringent levels of service need only be requested by a customer for short durations when the application needs it, and operator agrees to the SLA only when the infrastructure is able to support the demand. Second, AJIT uses trusted enclaves to do the accounting of packet deliveries such that neither the customer requesting guaranteed service levels for mission-critical applications, nor the operator providing the infrastructure support, can cheat.

The exponential growth in online content consumption is a key concern for designing future generation network architectures. In this paper, we use content access patterns from a large trace of content accesses comprising about half the population of United Kingdom to make the case that a large portion of the backhaul load can be mitigated by content sharing amongst edge devices. We explore various models for edge devices to store and share content amongst each other, ranging from reactive opportunistic sharing to predicting future content access and speculatively placing content on strategic devices prior to request. We analyse the performance of each of these models in terms of content placement and traffic savings, which are constrained by the storage available on edge devices, the performance of the speculation engine and the wireless channel conditions. We formulate and solve at scale an optimisation problem for strategically placing content for sharing within a geographically localised cell to show such an approach can save up to 47% of the traffic generated from a small cell.

The use of blockchains is growing every day, and their utility has greatly expanded from sending and receiving crypto-coins to smart-contracts and decentralized autonomous organizations. Modern blockchains underpin a variety of applications: from designing a global identity to improving satellite connectivity. In our research we look at the ability of blockchains to store metadata in an increasing volume of transactions and with evolving focus of utilization. We further show that basic approaches to improving blockchain privacy also rely on embedding metadata. This paper identifies and classifies real-life blockchain transactions embedding metadata of a number of major protocols running essentially over the bitcoin blockchain. The empirical analysis here presents the evolution of metadata utilization in the recent years, and the discussion suggests steps towards preventing criminal use. Metadata are relevant to any blockchain, and our analysis considers primarily bitcoin as a case study. The paper concludes that simultaneously with both expanding legitimate utilization of embedded metadata and expanding blockchain functionality, the applied research on improving anonymity and security must also attempt to protect against blockchain abuse.