Summary

• A five-year contract, extendable by five more, covers connectivity at over 300 utility sites.
• The proposed hybrid SD-WAN combines fibre, fixed-line, mobile and satellite paths with failover and segregation.
• PSTN migration and the proposed Cyber Security and Resilience Bill influence planning, but do not prove achieved compliance.

UK infrastructure specialist Vysiion has secured a five-year contract to replace South East Water’s wide area communications network, covering more than 300 dispersed sites that support water treatment, distribution, administration and monitoring.

The contract includes an option to extend for another five years. Vysiion, part of the Exponential-e Group, will work with Exponential-e using Cisco technology to deliver a managed hybrid software-defined wide area network, or SD-WAN.

Planned functions include diverse primary and secondary connections, automatic failover, centralised monitoring, encryption and separation between corporate IT and operational technology. These are contracted requirements and design intentions rather than independently verified improvements in uptime or recovery.

Communications serving water operations

South East Water supplies approximately 2.4 million customers across parts of Kent, Sussex, Surrey, Hampshire and Berkshire. Its dispersed facilities include offices, depots, treatment works, pumping stations and remote monitoring locations that may have limited connectivity choices.

Operational technology encompasses equipment and software controlling physical processes. SCADA systems help authorised staff monitor telemetry, receive alerts and interact with equipment across the network. Security and reliability requirements can differ from ordinary office connectivity.

A communications interruption does not automatically stop water treatment or pumping. The effect depends on whether local controls can continue safely, which functions require remote input and how staff are notified of changing conditions.

However, loss of visibility at an unmanned site can slow diagnosis or delay intervention. Network restoration and monitoring therefore contribute to overall resilience, alongside local safety systems, maintenance arrangements and reliable equipment power.

Designing for multiple connection failures

Vysiion plans to use fibre, other fixed lines, 4G/5G and satellite services, selecting suitable primary and secondary options at each location. Different sites may need different combinations because geography and availability vary across the estate.

SD-WAN can choose routes according to defined policies and shift traffic when a connection becomes unavailable or fails performance thresholds. Automatic failover is potentially useful for telemetry and administration, but it must be tested against application requirements.

Two nominally different carriers may share physical ducts, exchanges or supporting infrastructure. Genuine diversity requires examining underlying paths and failure domains, rather than assuming separate invoices necessarily indicate independent services.

Backup connectivity may also have different latency, bandwidth and availability characteristics. A path sufficient for periodic monitoring traffic may not support high-volume CCTV or time-sensitive operational functions without separate engineering decisions.

The announcement does not provide numerical recovery objectives, measured failover times or completed tests showing continuity during carrier outages. Those figures would be needed to judge whether the proposed architecture achieves the intended improvement.

Segregating IT and operational systems

The project includes separation between corporate IT and operational technology traffic. Network segmentation can help limit unnecessary movement between environments, reducing the potential consequences of compromised credentials or software in one area.

Segmentation is effective only when access rules, firewalls and permitted connections are configured appropriately. Maintenance access and vendor support are especially important where industrial devices have long service lives or limited security features.

Encryption protects data travelling over supported links but cannot correct a compromised endpoint or an authorised user misusing access. Central monitoring can reveal unusual patterns, yet its value depends on timely investigation and response.

Vysiion says its architecture is designed to support alignment with the National Cyber Security Centre’s Cyber Assessment Framework. That does not establish compliance across the entire utility, which also depends on organisational governance, testing and incident-management practices.

A deadline and a changing legal framework

PSTN-dependent sites are expected to receive priority during early migration, ahead of the planned 31 January 2027 retirement of traditional analogue telephone services. Legacy alarms and telemetry devices may require compatibility testing or replacement before they can use modern IP connections.

The Cyber Security and Resilience Bill was still progressing through Parliament on 27 October. Its proposed changes to critical infrastructure security requirements should therefore be treated as preparation for potential new duties, not obligations already in force.

Vysiion has not disclosed the contract price or a full completion schedule. The service will also require coordination between the utility, network carriers, equipment suppliers and operational staff to avoid unnecessary disruption during migration.

The supplier’s 27 October announcement establishes a significant planned modernisation programme. Verified outcomes will depend on completion across remote sites, tested failover behaviour, appropriate IT/OT controls and sustained performance after commissioning.

Project sequencing can affect service continuity. Replacing a connection that supports a live control process may require scheduled maintenance windows, temporary parallel links and local staff ready to verify telemetry when the new route is activated.

Contract management should clarify who monitors each link and who has authority to work with a carrier during an incident. Without agreed escalation responsibilities, a technically redundant network can still suffer prolonged disruption.

Operating costs will depend on the mix of connections used and the support required for remote sites. Satellite, mobile and fixed services have different commercial structures, and the announcement provides no basis for estimating savings from the eventual network.