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Setting up business broadband redundancy for internet backup
Few things are more infuriating than the internet dropping mid-task.
Broadband redundancy prevents this by providing a backup line. If one fails, the other takes over.
This guide explains how redundancy works and how to set it up, so your business stays online without disruption.
Content highlights
- Why do businesses need internet redundancy?
- How business broadband redundancy works
- How to set up a redundant internet system
What is business broadband redundancy?
Business broadband redundancy involves installing multiple internet connections at a premises to ensure uninterrupted connectivity.
These connections can actively balance internet loads to avoid congestion, or provide backup links if the primary line fails or degrades.
The more connections, and the more diverse their circuits, the greater the resilience.
For example, combining Openreach fibre, Virgin cable, and Starlink offers redundancy across circuit, provider and even transmission medium.
To maximise broadband resilience, the setup should also include an uninterruptible power supply (UPS) for power backup, and a secondary router or firewall for hardware failover.
All of this diversity converges at a Multi-WAN business broadband router, which serves as the central hub for redundant lines and manages intelligent traffic distribution.
Why do businesses need internet redundancy?
Modern businesses depend heavily on reliable internet connectivity. Nearly 70% use cloud-based applications, and around 30% rely on VoIP for customer communication.
This level of reliance means that even a short outage can seriously disrupt operations. Internet redundancy helps prevent this. Here are the key reasons, with real-world examples to illustrate each one:
Avoids operational downtime
Redundancy keeps on-site systems and services running without interruption.
Example: A logistics firm relies on live tracking dashboards in its warehouse. If the internet drops, operations simply stop until connectivity can be resumed.
Protects against revenue loss
Redundancy prevents missed transactions, failed payments, or interruptions that could breach service level agreements.
Example: A retail shop depends on its PoS system for in-store card payments. If the connection fails during a busy sales day, thousands of pounds in revenue could be lost as customers can only pay cash during the outage.
Ensures local service availability
Some critical apps are hosted locally or depend on on-site infrastructure.
Example: A law firm runs a document management system from its office servers. Without internet, staff and clients lose access. Redundancy ensures continuous availability.
Preserve communication systems
VoIP phones, SIP trunks, and internal comms tools need constant connectivity.
Example: A call centre uses a locally-hosted business VoIP phone system. If the internet fails, inbound and outbound calls are cut off. With redundancy, the switchover happens seamlessly.
Support remote workers
Office-hosted systems like VPNs must stay online for remote access.
Example: A remote design team connects to an office-based file server via VPN. If the office internet goes down, remote users are cut off from shared assets.
Meet compliance requirements
Some sectors require high availability for Service Level Agreements or regulatory compliance.
Example: A healthcare provider must guarantee 99.9% uptime for access to patient records, as mandated by regulators. Internet redundancy helps meet that standard.
How business broadband redundancy works
There are several ways to implement broadband redundancy at a business premises, but the underlying principles and technologies are broadly the same.
Let’s break down how it works, starting with the core hardware involved.
Redundancy hardware: Multi-WAN routers
A Multi-WAN router is normally the core of any broadband redundancy setup. This device acts as the central hub, connecting the multiple internet lines and managing how traffic flows between them.
Multi-WAN routers are purpose-built for broadband redundancy. They come with multiple Ethernet ports to support different connections and include built-in logic for failover and load balancing.
These routers are normally installed in the telecoms or server room, mounted on a rack alongside other networking equipment.
Note: For organisations with ultra-high uptime requirements (e.g. those targeting 99.999% or beyond), router-level redundancy may also be added. This involves using a separate, dedicated router for each internet connection, further reducing the risk of a single point of failure.
Redundancy management: Local, remote or SD-WAN
Managing broadband redundancy can be done in different ways depending on the business’s size, internal resources, and network architecture. Here are the most common approaches:
Managed by a business broadband provider
When using bundled connectivity, the broadband provider often supplies a plug-and-play Multi-WAN router with an integrated SIM or eSIM for mobile backup. Failover rules are configured remotely and managed as part of the service.
Managed in-house
Single site businesses with on-site IT staff usually choose to source their own broadband lines and manage their Multi-WAN router directly. Failover and load balancing rules are configured locally, offering maximum control and flexibility.
Managed by MSP
Organisations that outsource IT functions to a Managed Service Provider (MSP) have their router configurations handled remotely. The MSP monitors performance, applies failover rules, and optimises connectivity as needed.
Managed through SD-WAN
Larger or multi-site businesses often use SD-WAN for intelligent, centralised control of connectivity across their wide area network (i.e. site-to-site links, links to data centres and cloud platforms, and general internet connectivity).
SD-WAN engines push rules to local routers via API and can be part of a secure Secure Access Service Edge architecture or a fully managed WAN-as-a-Service cloud-native WAN service.
Redundancy logic: Failover or load balancing
So far, we’ve looked at the hardware and management approaches behind business broadband redundancy. The next piece is the redundancy logic, which determines how traffic is handled across multiple connections.
There are two primary methods: failover and load balancing, both of which rely on continuous network monitoring to operate effectively.
Failover (Active-Inactive)
Broadband failover keeps a secondary connection on standby (i.e. inactive) and automatically redirects traffic to it when the primary link (i.e. active) fails or underperforms due to issues like weather-related faults and line congestion.
This approach focuses on maximising uptime, ensuring that critical applications remain accessible during an outage or performance dip.
Load balancing (Active-Active)
Load balancing distributes traffic across multiple internet connections simultaneously. This boosts performance, prevents bottlenecks, and improves reliability, even when all lines are healthy.
For example, high-priority traffic (such as VoIP calls or security monitoring) can be routed through the primary line, while lower-priority tasks (like guest WiFi or file downloads) use the secondary connection. In effect, all physical lines act as a single, logical connection.
Network monitoring
Both failover and load balancing depend on real-time network performance data. Multi-WAN routers constantly monitor metrics such as latency, jitter, packet loss, and line availability.
This monitoring allows the router (or the cloud-based SD-WAN controller being fed the data through the API) to detect faults, assess connection quality, and make automatic, intelligent decisions about traffic routing, ensuring smooth switchover and optimal load distribution.
Physical path redundancy (separate broadband circuits)
Another key aspect of building internet resiliency is physical path redundancy: using multiple broadband connections that run over separate physical circuits.
The more independent your connections are from one another, the lower the chances that they’ll fail at the same time.
No internet connection is completely immune from failure (i.e. all networks ultimately connect to the UK’s core broadband infrastructure), but physical separation adds significant resilience.
Most outages occur in the last mile segment between the premises and the local exchange due to issues like damaged street cabinets, localised fibre faults, or mobile signal degradation from weather.
Below are some of the broadband circuit types businesses can combine for physical path redundancy, listed roughly by performance and resilience.
SoGEA
SoGEA broadband is a basic tethered connection using Openreach copper in the last mile and shared fibre in the distribution network. Vulnerable to failures at the street cabinet level and signal degradation due to its copper component.
Satellite
Offers an entirely uncorrelated path via satellite constellations. These business satellite broadband connections are becoming increasingly popular for backup. However, many satellite providers still rely on UK ground stations connected to the national core, so they’re not completely isolated.
LTE/4G/5G
Business mobile broadband connects via 4G or 5G antennas, bypassing traditional wired infrastructure. It usually links directly into the core network over dedicated backhaul. The biggest risks include poor weather affecting signal quality or antenna faults.
Cable
Delivered over Virgin’s coaxial cable broadband network, which operates independently from Openreach’s last-mile fibre and copper infrastructure. However, it still shares the core network further upstream.
Full fibre (Openreach or Altnet)
Fibre-to-the-premises (FTTP) using either Openreach or an Altnet (e.g. KCOM or Hyperoptic). While both offer separate fibre circuits, they can be vulnerable to faults in shared infrastructure or local fibre hubs. Altnets offer strong physical separation from Openreach at the local level.
Wireless leased line
Wireless leased lines deliver high speed internet using point-to-point microwave links. These bypass traditional ground infrastructure entirely for the last mile. They are highly resilient, even in poor weather, though dependent on rooftop or mast-mounted antennas and their backhaul connection.
Leased lines (Openreach or Altnet)
Business leased line broadband offers a dedicated fibre circuit directly from the provider to the premises. Businesses can combine leased lines from different suppliers (e.g. Openreach and an Altnet) to achieve true path diversity.
Dark fibre
Dark fibre is an enterprise-grade option where a business leases unused fibre and builds its own network infrastructure. While typically used for private networking, it can also be configured for the highest performance, fully dedicated internet connectivity.
ISP redundancy (separate logical paths)
Another important layer of broadband resilience is ISP (Internet Service Provider) redundancy, using internet services from separate business broadband providers.
Even if two providers use the same physical infrastructure (such as Openreach’s fibre network), each provider operates its own routing systems, DNS servers, and traffic management policies.
This means they offer separate logical paths to the internet, which can add significant resilience during service outages or performance degradation.
Additionally, each ISP comes with its own business broadband Service Level Agreement (SLA), committing to specific performance standards like uptime, latency, and support response times. This means your business can hedge against ISP-specific issues such as routing faults or bandwidth throttling.
There are dozens of business ISPs across the UK. Here are five of the best business broadband providers:
- BT business broadband
- Virgin Media business broadband
- TalkTalk business broadband
- Vodafone business broadband
- Sky business broadband
💡 Use our compare business broadband service to view providers and circuit options available at your location.
Power supply redundancy
The final piece of internet redundancy is ensuring routers and firewalls get continuous power to stay online.
If your router and other networking equipment rely solely on mains electricity, a power cut could bring down your entire connectivity setup, even if your internet lines remain active. While less common than internet drops, power outages caused by storms, fires, or local infrastructure damage do occur.
To mitigate this risk, many businesses install a UPS (Uninterruptible Power Supply), a battery-powered backup that automatically takes over when mains power fails. A UPS ensures the continuous operation of critical systems for a limited time.
Most businesses reserve UPS power for essential equipment, such as:
- Routers and network switches
- Security systems (e.g. CCTV)
- Refrigeration (in retail or healthcare)
- Emergency lighting
Some rural or high-risk sites also use petrol generators as backup. However, these typically require manual activation and aren’t ideal for seamless failover.
How to set up a redundant internet system
The best way to implement business broadband redundancy is to follow a clear, structured approach. Below is a general step-by-step guide suitable for organisations of all sizes and industries.
Step 1: Assess your redundancy needs
Start by evaluating how much resilience your business actually needs, and how much you’re willing to invest. More redundancy means more complexity and cost, so it’s important to strike a balance between protection and practicality.
Here are examples of typical business setups and their redundancy needs:
Small cafes, restaurants, and high street shops
Need reliable guest WiFi, card payment systems (PoS), and security IoT devices.
Recommended: Cost-effective, provider-managed redundancy with mobile failover.
Small offices or remote teams
Need to keep VoIP, UcaaS tools, and cloud apps running smoothly.
Recommended: Simple setup with auto-failover and basic network monitoring.
Retail chains or multi-site branches
Depend on real-time inventory, secure payment processing, and VPN access to HQ.
Recommended: Centrally managed SD-WAN solution with scalable multi-site redundancy.
Healthcare clinics or dental practices
Require high uptime for access to patient data and appointment systems.
Recommended: Path, logical, and power redundancy with a focus on uptime rather than performance.
Warehouses or logistics depots
Rely on warehouse mesh networks, scanners, fleet tracking, and real-time systems.
Recommended: Low-latency, high-uptime setup, in-house or third-party managed.
Tech startups or agencies
Use cloud collaboration tools (e.g., Git, Slack, Google Workspace), video calls, and may self-host services.
Recommended: High-performance, active-active load balancing and custom failover.
Enterprises and institutions
Mission-critical reliance on connectivity for productivity, security, and cybersecurity compliance.
Recommended: Full stack redundancy. Multiple ISPs, fibre/wireless paths, SD-WAN, power backup, and proactive monitoring.
Step 2. Choose your implementation method
Once you’ve defined your needs, the next step is to decide how to implement redundancy: internally, via your business ISP, or through a Managed Service Provider (MSP).
In-house implementation
Best for businesses with internal IT resources. Offers the most control and flexibility, with businesses choosing their hardware, management, logic, and path, logic and power redundancy.
ISP-managed implementation
Ideal for small business broadband needing a plug-and-play solution:
- Redundancy is included in the broadband package (e.g. 4G failover).
- Comes with a pre-configured Multi-WAN router.
- Managed remotely by the ISP.
- Cost-effective and low-maintenance.
Managed Service Provider (MSP) implementation
Suited to businesses without IT staff, or those with complex networking needs.
- MSP advises on required levels of redundancy.
- Handles procurement, setup, and ongoing management.
- Offers remote monitoring, SLAs, and full network support.
3. Deploy the redundancy solution
Whether handled in-house or externally, most deployments will follow a similar process:
Hardware installation
Install Multi-WAN routers and ensure compatibility with existing firewalls, VLANs, and dynamic DNS setups. For cloud-managed routers, grant the necessary access for SD-WAN overlays.
Configure redundancy logic
Apply failover and/or load balancing rules using the available internet connections, according to traffic priorities.
Set up monitoring
Redundancy logic depends on accurate real-time data about the performance of each connection. Deploy network monitoring tools compatible with your router or SD-WAN platform.
4. Test and audit regularly
Redundancy isn’t a “set and forget” system; it needs regular review:
- Conduct periodic tests of failover and load balancing behaviour.
- Audit your setup after adding new devices, VLAN rules, or broadband lines.
- Monitor for misconfigurations that could compromise performance or business broadband security.
If you’re using an MSP, audits are usually part of ongoing service and compliance checks. In-house teams should include redundancy testing in regular IT maintenance schedules.
Business broadband redundancy – FAQs
Our business broadband experts answer some of the most common questions around broadband redundancy for UK businesses.
What is a redundant fibre network?
A redundant fibre network is a setup where multiple, physically separate fibre routes (often called “diverse routing”) are used to avoid a single point of failure. If one fibre line is cut or damaged, traffic can automatically switch to a backup route.
For example, a business might combine an Openreach fibre connection with an Altnet fibre circuit that uses entirely separate infrastructure.
How do you calculate redundancy in a network?
A single formula doesn’t calculate redundancy. Instead, it’s assessed by examining each layer of resilience in the network:
- Physical path redundancy: Number of internet connections and their level of physical independence.
- ISP redundancy: Number of providers managing the logical paths.
- Power redundancy: Use of UPS or generator backup for continuity during outages.
- Redundancy logic: How failover and load balancing are configured.
A common framework is to aim for n+1 or n+2 redundancy, where n is the number of connections needed for normal operation, and +1 or +2 are backups.
What is 3-tier network redundancy?
Three-tier network redundancy refers to a hierarchical LAN design used in enterprise networks and data centres. While it forms part of connectivity resilience, it is separate from broadband redundancy which is resiliency at the edge of the local network.
3-tier network redundancy consists of:
- Core layer: High-speed backbone connecting major components.
- Distribution layer: Routing, security, and traffic management.
- Access layer: Where devices (users, printers, etc.) connect to the network.
Each layer is built with redundant switches, links, and power to prevent outages.
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