Keep your business connected when the main internet service fails
Your internet connection may support almost everything your organisation needs to operate.
It may carry:
- Microsoft 365
- Cloud applications
- Hosted Voice
- Microsoft Teams
- Video conferencing
- Customer systems
- Payments
- Remote access
- Security tools
- Backups
- Wi-Fi
- Connected devices
When the connection fails, the problem can spread across the whole business.
Employees cannot access cloud systems. Customer calls may stop. Video meetings disconnect. Payment terminals fail, and remote workers lose access to important services.
Most businesses understand that internet downtime is disruptive.
Fewer have a tested plan for what happens next.
Stratiis helps organisations design, install and manage internet failover using backup broadband, 4G, 5G, secondary circuits and automatic routing.
When the main connection fails, your backup should already know what to do.
What is internet failover?
Internet failover is the process of moving network traffic from a failed or unavailable primary connection to a backup service.
The change may happen:
- Automatically
- Manually
- Through a managed router
- Through a firewall
- Through an SD-WAN platform
- At provider level
- Through a combination of systems
A failover solution may use:
- 4G
- 5G
- Business broadband
- Full Fibre
- SoGEA
- A second leased line
- Fixed wireless access
- Satellite connectivity
- Another office
- Mobile applications
- Provider-level call routing
The right backup depends on how much of the business needs to continue during an outage.
Why do businesses need backup internet?
Internet access is no longer used only for web browsing and email.
For many organisations, it is the route to nearly every important business system.
An outage may affect:
- Customer telephone calls
- Repairs systems
- CRM
- Finance applications
- Payroll
- Customer portals
- Microsoft Teams
- Hosted Voice
- Remote desktops
- File access
- Cloud backups
- Payment systems
- Security monitoring
- Door-entry systems
- CCTV
- Connected devices
The business may still have working computers, phones and network equipment.
Without internet access, employees may not be able to use them effectively.
Backup connectivity reduces the risk that one failed line stops the organisation.
Is your current internet failover adequate?
You may already believe you have backup internet.
That does not always mean the business is protected.
You may recognise some of these problems:
- A mobile router is stored in a cupboard but never tested
- Backup requires someone to reconnect cables manually
- The failover SIM has expired
- Nobody knows the mobile data allowance
- The backup uses the same underlying network
- Hosted Voice does not work during failover
- The secondary line has never been activated
- Employees are told to use personal hotspots
- Static IP services fail when the connection changes
- Guest Wi-Fi consumes the backup capacity
- Cloud backups continue during an outage
- The failover device has weak signal
- The backup router is unsupported
- Nobody receives an alert when failover starts
- The business does not know when the main service returns
- The backup cannot support the number of employees on site
A backup service should be treated as part of the live network.
It needs monitoring, maintenance and regular testing.
Backup connectivity options
4G internet failover
4G failover uses the mobile network to provide backup internet.
It may be suitable for:
- Small and medium offices
- Branch locations
- Retail sites
- Temporary premises
- Remote locations
- Leased-line backup
- Business broadband backup
A 4G failover solution may include:
- A managed router
- Data-only SIM
- External antenna
- Automatic connection switching
- Usage alerts
- Security configuration
- Central monitoring
4G can provide a practical backup because it uses different infrastructure from many fixed internet services.
Coverage and capacity still need to be tested.
5G internet failover
5G may provide higher speeds and lower delay in suitable areas.
It may support:
- More employees
- Video meetings
- Hosted Voice
- Cloud applications
- Larger file transfers
- Temporary offices
5G availability and performance can vary by:
- Location
- Building materials
- Network
- Time of day
- Router
- Antenna placement
- Local congestion
A strong outdoor signal may not provide a strong indoor service.
The connection should be tested where the router will be installed.
Multi-network mobile failover
A standard SIM normally uses one mobile network.
A multi-network service may connect through different available networks depending on the service and location.
This can help when:
- Sites are spread across Scotland
- One network is weak in certain buildings
- Locations change
- Greater mobile resilience is required
- A standard national contract does not provide consistent coverage
A multi-network service does not guarantee connectivity everywhere.
The router, antenna and building still affect performance.
External mobile antennas
A mobile router installed inside a communications cabinet may receive poor signal.
An external antenna can sometimes improve:
- Signal strength
- Connection stability
- Upload speed
- Download speed
- Access to 4G or 5G
- Reliability
The antenna may be installed:
- On a wall
- On a roof
- Near a window
- Outside the building
- In another part of the premises
Installation should consider:
- Cable length
- Weather protection
- Building permissions
- Signal direction
- Physical security
- Lightning and surge protection
- Maintenance access
Backup business broadband
A second fixed broadband service may provide more capacity than mobile failover.
It may be suitable for:
- Larger offices
- Sites with many users
- Video-heavy organisations
- Contact centres
- Locations with weak mobile coverage
- Businesses requiring longer outage support
The secondary connection may use:
- Full Fibre
- SoGEA
- Another business broadband product
- A different carrier
The design should check whether both connections share:
- The same local duct
- The same exchange
- The same provider network
- The same building entry point
- The same power supply
Two services do not automatically mean true resilience.
Backup leased lines
Some critical organisations may require two leased lines.
This may be appropriate where:
- A major office cannot operate without internet
- A contact centre depends on cloud calling
- Customer systems are business-critical
- Large numbers of employees work at one site
- High capacity is needed during failover
- Mobile or broadband backup is insufficient
The design should consider:
- Different providers
- Different routes
- Different building entry points
- Separate routers
- Separate firewalls
- Separate power
- Diverse exchanges where available
True diversity can increase cost significantly.
The level of resilience should match the cost of downtime.
Fixed wireless and alternative connectivity
Some sites may use fixed wireless connectivity as a backup.
This can involve a radio connection between the premises and a provider location.
It may be useful where:
- Fixed-line options are limited
- Mobile coverage is weak
- A separate physical route is needed
- The site is remote
- Rapid deployment is required
Performance may be affected by:
- Line of sight
- Weather
- Distance
- Provider infrastructure
- Building access
- Antenna position
Specialist availability checks are normally required.
Satellite failover
Satellite connectivity may be considered for remote sites where fixed and mobile alternatives are unavailable.
It may support:
- Remote operations
- Rural locations
- Emergency connectivity
- Temporary sites
The service may involve:
- Higher delay
- Installation requirements
- Clear sky visibility
- Weather effects
- Data policies
- Specialist equipment
- Higher cost
Satellite may be valuable as a final-resort or remote-location option.
It may not be the best fit for every cloud voice or real-time application.
Failover technology
Automatic or manual failover?
Automatic failover
Automatic failover allows the router, firewall or SD-WAN platform to detect a fault and move traffic to the backup connection.
It may provide:
- Faster recovery
- Less employee involvement
- More consistent response
- Central monitoring
- Automatic return to the main service
Automatic failover is usually appropriate where internet access is important to business operations.
Manual failover
Manual failover requires someone to take an action.
This may involve:
- Reconnecting cables
- Changing router settings
- Starting a mobile router
- Moving employees to another network
- Contacting the provider
Manual failover may be acceptable for very small offices, low-dependency sites, temporary arrangements and rarely used locations.
It introduces delay and depends on the right person being available.
How does automatic failover work?
A router, firewall or SD-WAN device monitors the primary connection.
It may check:
- Whether the circuit is physically connected
- Whether the provider gateway responds
- Whether internet destinations can be reached
- Whether packet loss is excessive
- Whether delay is unacceptable
- Whether the route remains usable
When the system decides that the main service has failed, it moves traffic to the backup connection.
The process should define:
- How quickly a fault is detected
- How many failed checks trigger failover
- Which traffic moves
- Whether active sessions survive
- When the system returns to the primary line
- Who receives an alert
- What happens if both connections fail
The settings should avoid switching unnecessarily because of one brief interruption.
What is a dual-WAN router?
A dual-WAN router can connect to two internet services.
For example:
- A leased line and Full Fibre broadband
- Business broadband and 5G
- Two fixed broadband services
- A leased line and 4G
The router can be configured to:
- Use one service as primary
- Use one service as backup
- Share traffic between both services
- Route certain applications through a specific connection
- Switch automatically during a fault
The router must be sized for the total bandwidth and security requirements.
Firewall-based failover
Many business firewalls can manage more than one internet connection.
This may allow the firewall to:
- Monitor both services
- Move traffic automatically
- Apply security policies to the backup
- Restrict non-essential usage
- Maintain VPNs
- Alert the support team
- Record failover events
The firewall should be configured and tested carefully.
A backup connection should not bypass the security controls applied to the main service.
SD-WAN failover
SD-WAN can manage traffic across several connections.
It may:
- Monitor link quality
- Choose the best available path
- Prioritise important applications
- Switch when packet loss increases
- Use several connections together
- Provide central visibility
- Apply site-wide policies
This may be useful for multi-site organisations.
It may be unnecessary for a small business that needs only simple primary and backup internet.
Does the backup need to match the main connection?
Not always.
A business may use a 1 Gbps leased line during normal operation but rely on a lower-speed broadband or mobile service during an outage.
The backup may need to support only essential services such as:
- Customer calls
- Microsoft Teams
- Core cloud applications
- Payments
- Remote support
- Critical business systems
Non-essential services may be restricted, including:
- Guest Wi-Fi
- Cloud backups
- Large downloads
- Streaming
- Software updates
- Personal devices
- Non-urgent video
The business should decide in advance what remains available during failover.
Failover and key business services
Internet failover and Hosted Voice
Hosted Voice depends on internet connectivity.
When the main service fails, calls may continue through:
- The backup internet connection
- Mobile applications
- Another office
- Provider-level diversion
- An external answering service
- Voicemail
The failover design should confirm:
- Whether phones re-register automatically
- Whether active calls drop
- Whether the backup supports enough calls
- Whether firewall rules apply
- Whether number routing changes
- Whether remote users remain available
- What happens during a power cut
Provider-level call diversion
Provider-level call diversion can redirect incoming calls when the office phone system or internet connection is unavailable.
Calls may be sent to:
- Another office
- Mobile phones
- A cloud application
- An answering service
- A disaster-recovery queue
- Voicemail
This can provide continuity even when the local site is completely offline.
The routing should be configured and tested before an incident.
Internet failover and Microsoft Teams
Microsoft Teams may continue working through a backup connection.
The user experience depends on:
- Backup bandwidth
- Upload performance
- Mobile signal
- Number of users
- Video use
- Firewall configuration
- Traffic prioritisation
During failover, the organisation may decide to:
- Continue audio calls
- Limit high-definition video
- Restrict large meetings
- Reduce screen sharing
- Ask some employees to work remotely
- Move important meetings to another site
Static IP addresses during failover
A business may use static IP addresses for:
- VPNs
- Cloud allow lists
- Remote systems
- Hosted services
- Supplier access
- CCTV
- Specialist applications
When traffic moves to another provider, the public IP address may change.
This can affect:
- Remote access
- Cloud security rules
- Site-to-site VPNs
- Hosted applications
- Supplier integrations
The failover design may use:
- Dynamic DNS
- SD-WAN
- VPN gateways
- Cloud security services
- Provider-managed addressing
- Updated allow lists
- More advanced routing
Static IP continuity should be reviewed before the backup service goes live.
Power resilience
Internet failover does not help when the building has no power unless the required equipment is protected.
This may include:
- Primary router
- Backup router
- Firewall
- Network switches
- Wi-Fi access points
- Optical network terminal
- Mobile antenna equipment
- IP phones
- Servers
Possible protections include:
- Uninterruptible Power Supplies
- Generator power
- Battery backup
- Mobile devices
- Alternative sites
- Provider-level call diversion
Power resilience should be included in the wider continuity plan.
Testing internet failover
Failover should be tested before it is needed.
Testing may include:
- Disconnecting the primary service
- Confirming automatic detection
- Checking backup activation
- Testing cloud applications
- Testing Hosted Voice
- Testing Microsoft Teams
- Testing VPNs
- Testing static IP dependencies
- Checking monitoring alerts
- Measuring switchover time
- Confirming return to the main connection
- Reviewing backup capacity
Testing should be planned carefully to avoid unnecessary business disruption.
Internet failover for different sectors
Accountancy firms
Accountancy firms may depend on connectivity for:
- Cloud accounting
- Payroll
- Microsoft 365
- Client portals
- Tax applications
- Hosted Voice
- Video meetings
- Remote access
An outage during payroll or filing deadlines can create serious pressure.
The failover plan should prioritise core cloud applications, client communication, Teams, Hosted Voice, secure file access and remote working.
Housing associations
Housing associations may rely on internet access for:
- Housing-management systems
- Repairs services
- Tenant communication
- Customer contact centres
- Contractor systems
- Microsoft Teams
- Hosted Voice
- CCTV
- Door entry
- Connected building systems
A head office or contact centre may require strong fixed-line resilience.
A smaller local office may use mobile failover.
The design should reflect the impact on tenants and customer service.
Charities
Charities may need continuity for:
- Service-user communication
- Donor systems
- Volunteer coordination
- Microsoft 365
- Cloud applications
- Remote working
- Helplines
- Community services
Cost is important.
A managed 4G or 5G backup may provide practical protection without the cost of two dedicated fixed connections.
Professional services firms
Professional services organisations may rely on:
- Client portals
- Microsoft Teams
- Secure file access
- Hosted Voice
- Cloud applications
- Video meetings
- Remote working
A short outage can affect customer experience and billable work.
The backup design should protect the services required to continue client communication.
Contact centres
A contact centre may need strong resilience because internet failure can affect:
- Calls
- CRM
- Recording
- Analytics
- Web chat
- Customer information
- Remote agents
Possible continuity measures include:
- Two fixed connections
- Different providers
- Mobile backup
- Provider-level call diversion
- Remote working
- Alternative office routing
- Cloud contact-centre platforms
The failover capacity should support the expected number of agents.
Retail and customer sites
Retail and customer-facing sites may rely on connectivity for:
- Payments
- Stock systems
- Bookings
- Customer Wi-Fi
- CCTV
- Digital signage
- Hosted Voice
- Cloud applications
Even a small location may need failover when payment processing depends on the internet.
The backup service should be tested with the real payment equipment.
Our internet failover process
1
Discovery
We begin by understanding:
- Primary internet connection
- Number of users
- Locations
- Cloud applications
- Hosted Voice
- Microsoft Teams
- Video conferencing
- VPNs
- Customer systems
- Payment services
- Connected devices
- Business impact of an outage
- Maximum acceptable downtime
- Current continuity arrangements
2
Existing resilience audit
We review:
- Current backup services
- Routers
- Firewalls
- SIMs
- Data plans
- Mobile signal
- Secondary circuits
- Failover configuration
- Static IPs
- VPNs
- Power protection
- Monitoring
- Previous outages
- Test history
3
Site and coverage assessment
We assess:
- Fixed-line availability
- 4G coverage
- 5G coverage
- Multi-network options
- Router location
- Antenna requirements
- Building materials
- Communications cabinet
- Power
- Cabling
- Alternative providers
- Physical route diversity
4
Business-priority review
We identify which services must continue.
These may include:
- Hosted Voice
- Microsoft Teams
- Customer-service systems
- Finance
- Payments
- Cloud applications
- Remote access
- Security monitoring
- Connected devices
We also identify which traffic can be restricted.
5
Solution design
We recommend the appropriate combination of:
- Backup broadband
- 4G
- 5G
- Multi-network SIM
- Secondary leased line
- Dual-WAN router
- Managed firewall
- SD-WAN
- External antenna
- UPS
- Monitoring
- Traffic prioritisation
- Provider-level call diversion
We explain the expected capacity and limitations.
6
Installation and configuration
We configure:
- Primary and backup links
- Router or firewall failover
- Health checks
- Traffic policies
- Static IP handling
- VPNs
- Hosted Voice
- Monitoring
- Alerts
- Mobile data controls
- Return-to-primary rules
7
Testing
We test:
- Primary connection failure
- Backup activation
- Cloud applications
- Hosted Voice
- Microsoft Teams
- Video conferencing
- VPNs
- Static IP dependencies
- Remote access
- Mobile performance
- Monitoring alerts
- Return to normal service
8
Documentation and runbook
We document:
- Primary connection
- Backup connection
- Provider details
- Router and firewall
- SIM information
- Failover behaviour
- Priority services
- Restricted traffic
- Support contacts
- Employee communication
- Testing schedule
- Escalation process
9
User and management communication
We explain:
- What happens during an outage
- Which services remain available
- Which services may be restricted
- Who receives alerts
- How incidents are communicated
- How support is contacted
10
Ongoing support and testing
Stratiis can continue to support:
- Connection faults
- Provider escalation
- Routers
- Firewalls
- Mobile services
- Data usage
- Signal
- Failover events
- Testing
- Static IP changes
- VPNs
- Office moves
- New sites
- Capacity reviews
- Contract renewals
Frequently asked questions
What is internet failover?
Internet failover moves network traffic to a backup connection when the main internet service becomes unavailable.
Can internet failover happen automatically?
Yes.
A suitable router, firewall or SD-WAN platform can detect a fault and switch to the backup connection.
How quickly does internet failover happen?
The time depends on the equipment and configuration.
It may take from a few seconds to longer while the system confirms the primary connection has failed.
Some applications may need to reconnect.
Will active calls stay connected?
Not always.
Hosted Voice and Teams calls may drop when the public internet route changes.
New calls may work once the service reconnects through the backup.
Is 4G suitable for internet failover?
Yes, where coverage and capacity are suitable.
It is commonly used for small and medium offices and branch locations.
Is 5G better than 4G?
5G may provide more capacity in suitable locations.
4G may provide stronger or more consistent coverage elsewhere.
The service should be tested at the site.
What is a multi-network SIM?
A multi-network SIM may connect through several available mobile networks rather than one network only.
Do we need an external antenna?
Possibly.
An external antenna can improve mobile signal where the router is installed in a poor-signal location.
Can backup internet support Microsoft Teams?
Yes, when the backup provides suitable bandwidth, upload speed and stability.
Video may need to be restricted during a lower-capacity outage.
Can it support Hosted Voice?
Yes.
The router, firewall and phone platform should be tested to confirm calls can reconnect through the backup service.
Can failover support a whole office?
Possibly.
The answer depends on the number of users, backup capacity and which services remain available.
Does backup internet need to be as fast as the main line?
No.
It should be capable of supporting the organisation's agreed essential services.
Can guest Wi-Fi be turned off during failover?
Yes.
The firewall or wireless platform may restrict guest access to protect business capacity.
What happens to our static IP address?
The public IP may change when traffic moves to another provider.
This can affect VPNs, allow lists and hosted services.
The design should address this before deployment.
Will site-to-site VPNs still work?
They may reconnect automatically when correctly configured.
Testing is required because the backup may use a different public IP.
Can two broadband connections fail at the same time?
Yes.
They may share local ducts, exchanges, provider infrastructure or building equipment.
Does using two providers guarantee diversity?
No.
Different providers can still use the same physical network route.
Can failover protect against a router failure?
Only when the design includes separate or resilient router equipment.
A second internet circuit connected to one failed router may not help.
Can failover protect against a power cut?
Only when the router, firewall, switches and related equipment have backup power.
How often should failover be tested?
Testing frequency depends on the importance of the site.
Critical locations may require quarterly or twice-yearly testing, as well as testing after major changes.
Does the mobile SIM need a data allowance?
Yes.
The plan should reflect expected outage use and include usage monitoring.
Can we use employees' mobile hotspots?
They may provide a limited emergency workaround.
They are not a well-managed business continuity solution and can create security, coverage and support problems.
Can Stratiis monitor when failover activates?
Yes.
Where supported by the router, firewall or connectivity service, Stratiis can monitor and alert on failover events.
How much does internet failover cost?
The cost depends on:
- Backup technology
- Mobile data plan
- Router
- Firewall
- External antenna
- Secondary fixed line
- Installation
- Monitoring
- Static IP requirements
- SD-WAN
- Power protection
- Support
A site and business-impact review is normally required before accurate pricing can be provided.
Do not wait for the next outage to discover whether your backup works
Internet failover is not simply a spare router or unused mobile SIM.
It is a complete continuity process.
The backup connection needs enough capacity. The router and firewall need to switch correctly. Hosted Voice, Microsoft Teams, VPNs and cloud applications need to be tested.
Employees also need to understand which services remain available and which activities should stop during an outage.
Stratiis can help you design and manage internet failover around the real impact of downtime on your organisation.
Let's build and test a backup connection before your main internet service fails.
