Blackout-proof network infrastructure: what 28 April taught businesses

• More than 8 hours That is how long Lisbon waited for electricity after the 11:33 outage.
• Cascade effect ANACOM, Portugal's communications regulator, concluded that the power failure affected mobile and fixed networks; a backup of the same type can go down with the main line.
• The backbone first UPS for the network, internet over independent paths (including satellite), critical systems in the cloud or a datacentre and phones that ring anywhere.
• One page, one test a year The plan fits on a single sheet and is only worth anything if it is rehearsed.

In that interval, many companies discovered that their server was off, the internet was down, the landlines were silent and nobody had the authority to decide. ANACOM's report to the Government recommended assessing the autonomy of batteries and generators and setting minimum autonomy times for network equipment. For a company, the conclusion is straightforward: two contracts using the same technology are not redundancy.

Keeping 40 desktop computers running for 8 hours makes no sense. What makes sense is keeping the network, the connection to the outside world and the systems where the work lives running — and letting the rest switch off.

The role of the UPS, explained without jargon

A UPS is a battery that kicks in the instant the mains supply fails. It keeps the essentials running for a while and allows servers to be shut down without corrupting data. A UPS designed for 10 minutes will not last 8 hours: you choose it by how long you want to hold out, and only for the equipment that counts.

A typical sizing

Example — an office with 25 people on laptops and a local file server. The network UPS powers only the router, firewall, core switch, two Wi-Fi access points and the satellite dish. The server has its own UPS that shuts it down safely after 15 minutes. The team keeps email and cloud for the planned hours and the server starts up afterwards without damage — for far less than it would cost to protect the whole office.

There is only redundancy when the failure of one path does not drag the other down with it. Two fibres from the same carrier coming in through the same duct do not count.

1. Main fibre — your primary carrier.
2. Second carrier — preferably using a different technology.
3. Satellite — for those who cannot stop, a link such as Starlink depends less on local terrestrial infrastructure and, with a UPS, keeps the office online when local networks fail.
4. Managed firewall — decides on its own, within seconds, which path traffic takes when one goes down.

The options are covered in detail in our article on business internet speed and redundancy.

ReStream, a Texas-based technology company and a global leader in multi-platform live streaming, entrusted its Cascais office to DataRoad. The network now has layer 3 PoE switches at the core, Wi-Fi 6, an enterprise firewall, a Starlink link for a robust and redundant connection and permanent monitoring, all managed under an IT Unlimited contract. For a business that lives by being live, the question "what if the internet goes down?" had to be answered before it was asked — and every SME should ask it.

We recommend what we use. DataRoad's datacentre has redundant internet, Starlink and advanced renewable energy systems, and it is from there that international clients work remotely. This is the foundation of our remote working and mobility solutions, designed for companies that have to keep going when the office closes.

A business continuity plan does not need 80 pages. For a blackout, one printed sheet covers the essentials:

1. Who decides? — the name and mobile number of whoever declares blackout mode, and a deputy.
2. How do we communicate? — a defined messaging group and a contact list on paper.
3. What stays on, and for how long? — the list in the table above, with the real autonomy of each UPS.
4. Where does the team work? — at home, another office or a space with power, with remote access already tested.
5. What do we tell clients? — a template message ready for email, website and social media.
6. How do we come back? — the start-up order for equipment and confirmation that backups ran, following the method in our guide to backup and disaster recovery for SMEs.

A plan that has never been tested is just an assumption. Once a year, at the end of the day, cut the power to the network and watch what happens.

Under IT Unlimited contracts, we size the UPS units, configure redundant internet with automatic failover and monitor the equipment — we know an office has lost power before the client calls. For those who cannot stop out of hours, the IT Unlimited Premium 365 plan covers nights, weekends and public holidays. Our head office is in Alfragide and our support reaches the whole country.

We assess UPS units, internet connections, critical systems and how the team works without power, and deliver the one-page plan with priority fixes. No-obligation proposal. More than 10 workstations · support contract · remote, on-site and telephone support.

• ENTSO-E — Iberian Peninsula Blackout, 28 April 2025
• Government of Portugal — Extraordinary Council of Ministers of 29 April 2025
• Government of Portugal — ANAC, ANACOM and IMT submit reports on the impact of the blackout
• Lusa (via DNoticias) — Parliamentary hearing of the chairman of E-Redes
• Lusa (via DNoticias) — REN and E-Redes: grid 100% restored