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How do leased lines work?
Leased lines are the pinnacle of business broadband, offering uncontended bandwidth, symmetrical Gigabit speeds, 99.99% uptime guarantees and airtight cybersecurity.
On the downside, leased lines are costly, troublesome to install, and usually require overhauling your local network to support them.
This article discusses how leased lines work, how they compare to standard broadband, and what to consider before switching.
Contents
- What is leased line broadband?
- How does a leased line work?
- Leased line vs standard full fibre (FTTP)
- Use cases for leased line
- Switching considerations
What is leased line broadband?
Leased line broadband is a dedicated, uncontested, end-to-end fibre optic connection between your business premises and your the exchange of your business broadband provider, bypassing local cabinets and other bottlenecks of the shared fibre network.
The key benefits include:
- Fastest speeds: Speeds that can scale up to 10 Gbps.
- Consistent bandwidth: Performance remains unaffected by network congestion.
- Stability: Offers the lowest latency, jitter, and packet loss of any connection.
- Symmetrical broadband: Ideal for cloud applications like VoIP, UCaaS, and demanding collaborative tools.
- Enhanced security: Provides the most secure broadband connection and configuration.
- Failover: Supports backup connections for business-critical broadband.
- Service guarantees: Service Level Agreements (SLAs) guarantee 99.99% uptime and issue resolution within six hours.
- Scalability: Leased lines are installed with bearer capacity for speed upgrades.
Leased line broadband is unmatched. Let’s delve into how leased lines achieve these advantages.
How does a leased line work?
Leased lines are the only direct connection to the exchange, offering the most direct route to your provider’s core network.
Let’s look at its key features to understand how it achieves this:
Dedicated fibre connection
A leased line connection comprises a private, high-performance fibre cable running from your property directly to the nearest exchange. The entire bandwidth of this line (i.e. the “bearer capacity”) is exclusively reserved for your business’s internet traffic.
Once at the exchange, your traffic joins the provider’s core high-speed network with preferential access, ensuring your connection remains uncontested even when circulating in the shared network.
It’s like having dual-carriageway private access to the nearest motorway and then getting private fast lanes in the public motorway network. Regardless of congestion, your lanes will always be reserved for your traffic, so driving to work and back will always be ultrafast and take the same time.
Avoids local cabinets
In contrast, all other tethered business broadband connections, including full fibre, SoGEA, and Virgin Cable, must go through local cabinets before joining the exchange.
These local cabinets act as junctions for these shared bandwidth connections. A single connection to a Openreach cabinet supports either 50 homes or 5 business connections.
Being junctions, these local cabinets are key congestion points in the local network that leased lines completely avoid.
Using shared ducts for routing
Leased line fibre cables require a network of underground ducts to connect your premises with the exchange.
Therefore, the feasibility of a leased line depends on the availability of existing underground ducts between the two points, as the logistics and cost of laying new ducts make it time-consuming and expensive.
The underground duct network is dense in urban areas of the UK but is sparse or non-existent in rural areas. This makes your business location relative to ducts and exchanges key to its feasibility.
Support of failover connections
Business broadband routers that support symmetrical, high bandwidth connections like leased lines are enterprise-grade, which also supports multiple simultaneous connections.
Businesses that opt for a leased line usually take full advantage of this and acquire a backup or failover connection parallel to their primary one to achieve broadband redundancy.
For more information read our full guide to leased line failover solutions.
Leased line vs standard full fibre (FTTP)
A leased line is a significant step up from standard full fibre. Let’s compare them to understand why:
| Leased Lines | Standard full fibre | |
|---|---|---|
| Speed | Up to ~10 Gbps, scalable as needed. | Up to ~1 Gbps, varies by plan. |
| Stability | Ultra-Stable: - Low latency (<5ms), - Minimal jitter (<1ms), - Negligible packet loss (<0.1%). | Stable: - Low-to-moderate latency (10–25ms), - Jitter (2–5ms), - Occasional packet loss (<1%). |
| Bandwidth symmetry | Symmetrical: Equal upload and download speeds, essential for business-critical applications. | Asymmetrical: Download speeds typically multiple times faster than upload speeds. |
| Bandwidth contestion | Uncontested: Dedicated bandwidth using private fibre strands, unaffected by other users’ traffic. | Contested: Bandwidth shared via GPON (Passive Optical Network), variable during peak traffic hours. |
| Security | High Security: Dedicated traffic lane with VLAN configuration, private routing, and enhanced broadband cybersecurity features. | Standard Security: General broadband cybersecurity features; shared traffic may expose risks. |
| SLA guarantees | Enterprise-Grade: 99.99% uptime with guaranteed 6-hour fault resolution (or less). | Best-Effort Basis: ~95–99% uptime with resolution times of 24-48 hours only available in premium package. |
| Architecture | Point-to-Point: Private, dedicated fibre strands connecting customer premises directly to the provider’s network (PoP). | Shared GPON: A single fibre is split using passive optical splitters, serving multiple premises from a central Optical Line Terminal (OLT). |
| Scalability | Highly Scalable: Easily upgraded to higher bandwidth (10+ Gbps or more) without affecting other users. | Moderate Scalability: Limited by GPON splitters and shared bandwidth; upgrades may require infrastructure changes. |
| Cost | Higher, starting at £300–£1,000+ per month depending on bandwidth and location. | Lower, ranging from £30–£100 per month depending on the package. |
Use cases for leased line
The unmatches performance, service and security of a leased line are key for multiple business use cases, including:
VoIP systems
Businesses using cloud-based VoIP phone systems benefit from the stability (i.e. incredibly low latency, jitter and packet loss) and reliability (99.99% uptime plus redundancy) of leased lines. These features ensure crystal-clear VoIP call quality, even for large-scale or high-volume phone systems.
Cloud applications and security
The symmetry (equal upload and download speeds) and high bandwidth of leased lines make it ideal for any cloud-hosted application that requires a heavy data stream to work effectively.
This includes cloud-based cybersecurity software that relies on constantly monitoring your network.
Hosting services
The same applies to businesses hosting websites and other applications; they need an uninterrupted, high-bandwidth connection to ensure customers have a high-quality experience, especially during high congestion times.
Multi-site connectivity
Leased lines allow wide-area network systems like SD-WAN traffic optimisation and SASE secure, cloud-ready architecture to work under ideal conditions. These can work with inferior connections, but their effectiveness is greatly reduced (e.g., traffic routing is impaired, and network monitoring is limited), reducing the effectiveness of these tools designed to support enterprise needs.
Financial services
Professional traders use leased lines to ensure the fastest, lowest latency connections and reduce the risks of delays in their trades. A laggy connection could lead to unnecessary losses, certainly above the premium for a high-performance connection.
Disaster recovery
Leased lines are critical in remote backups and disaster recovery because of their high upload speeds. These speeds are necessary for maintaining off-site backups and ensuring swift data restoration during emergencies.
Leased line considerations for your business
Every business would have a leased line if it were plug-and-play, available everywhere and affordable. Consider the following before hastily switching to a leased line:
Feasibility
The first obvious blocker to a leased line is its feasibility. The easiest way to check is by requesting a callback from our leased line experts, who can tell you precisely what providers (if any) are available in your area without commitment.
It is complex to check the feasibility independently because it depends on:
- Existing fibre infrastructure: Leased lines are only possible within a reasonable distance from a provider’s exchanges and when underground ducts are available for routing.
- Provider-specific exchanges: Many leased line providers manage their own private leased line exchanges and networks to gain an advantage over those relying on Openreach or KCOM.
If no fibre infrastructure is available, consider grouping with neighbouring homes and businesses in eligible areas of the Gigabit Broadband Voucher Scheme (GBVS). This may not guarantee a leased line, but it will undoubtedly make it more viable.
Performance requirements
To many SMEs, a leased line may be overkill. This is especially true in non-critical sectors where broadband is used for ordinary office tasks like small-scale video conferencing, email, and simple cloud-based collaboration environments like Google Suite.
Standard full fibre, Virgin Cable or SoGEA broadband can handle these use cases. If reliability is important, 99.99% uptime can be achieved by combining any low-spec connection with a 5G/4G or business satellite broadband, especially in areas without access to fibre.
Use our broadband speed calculator to estimate your business’ bandwidth requirements.
Costs
Leased lines cost £300 to over £1,000 per month, far more than standard broadband solutions. One-time installation and local network upgrade costs, which can creep into the five figures, also need to be considered.
However, these costs can be significantly decreased by committing to a longer-term contract (3+ years) and bundling a leased line with other services like UCaaS with the help of a managed leased line provider.
See our detailed guide to leased line broadband prices for more details.
Local network upgrades
A leased line is as good as its biggest bottleneck. There is no point in having unmatched performance from your router outwards if an inadequate local network (the route from your router to your devices) causes slowdowns.
The installation of a leased line is usually coupled with a local network upgrade, which may include:
- Network switches: Required for network segmentation (security and traffic management) and VLANs (security).
- Mesh networks: Required to ensure your new high-bandwidth WiFi signal is optimally spread across your premises.
Managed leased line
You have the choice between a managed and unmanaged leased line.
A managed service is ideal for businesses without a dedicated IT department, as network management and broadband cybersecurity can be fully outsourced. These are offered by providers that work with multiple services that can bundle packages, like leased line + VoIP + SD-WAN, reducing the costs of individual services.
In contrast, an unmanaged leased line suits businesses with enough IT resources to handle it. It offers full control over network configurations while the provider handles installation and maintenance. The choice depends on your need for convenience versus flexibility.
Cybersecurity
Businesses in critical sectors like healthcare or finance must meet strict cybersecurity compliance requirements. A leased line makes this more accessible with its in-built enhanced security compared to standard broadband.
The ample bandwidth can resist persistent DDoS attacks and leave enough bandwidth for cybersecurity software monitoring to continue. At the same time, enterprise-grade leased line routers offer advanced firewall configurations, VLANs for segmentation in case of a successful attack, and intrusion detection for enhanced protection.
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