Understanding the Fundamental Difference

The simplest way to understand the difference between a fibre leased line and broadband is this: broadband is a shared road, and a leased line is your own private motorway. With broadband, you share bandwidth with hundreds of other users in your area. With a leased line, every megabit of bandwidth is exclusively yours.

For businesses in Belfast and across Northern Ireland, this distinction matters enormously. When your team relies on VoIP phones from Yealink or Avaya, cloud-based applications, and video conferencing, a shared connection that slows down at peak times is not just inconvenient — it directly impacts productivity and revenue.

Speed: Advertised vs Guaranteed

Broadband providers advertise speeds with phrases like "up to 80Mbps" or "average download speed of 63Mbps." These are estimates, not guarantees. Your actual speed depends on distance from the exchange, network congestion, and time of day.

A leased line guarantees the speed you pay for. If you order a 100Mbps leased line, you get 100Mbps — consistently, 24 hours a day, 365 days a year. There is no "up to" qualifier.

• FTTC Broadband: Up to 80Mbps download / 20Mbps upload (actual speeds vary)
• FTTP Broadband: Up to 900Mbps download / 110Mbps upload (shared, contended)
• Leased Line: 10Mbps to 10Gbps symmetric (guaranteed, uncontended)

Symmetry: Why Upload Speed Matters

Standard broadband is asymmetric — download speeds are much faster than upload speeds. This is fine for browsing and streaming, but businesses need upload speed for:

• VoIP and video conferencing (sending audio and video upstream)
• Uploading files to cloud storage and backup services
• Sending large email attachments and documents
• CCTV footage uploading to cloud recording platforms
• Hosting servers or applications on-premises

A leased line delivers symmetric speeds. A 100Mbps leased line gives you 100Mbps download and 100Mbps upload. For businesses running Panasonic or Yealink phone systems alongside cloud applications, this symmetry ensures consistent call quality regardless of what else is happening on the network.

Contention Ratios: Shared vs Dedicated

Contention ratio describes how many users share the same bandwidth. Standard broadband typically has contention ratios of 20:1 to 50:1, meaning up to 50 premises share the same backhaul capacity. During peak hours (9am-5pm for business areas), this sharing causes noticeable slowdowns.

A leased line has a contention ratio of 1:1. The bandwidth is exclusively yours. This is why leased lines deliver consistent performance regardless of time of day or what your neighbours are doing. For a deeper understanding of why this matters, see our guide on what an SLA means for business internet.

SLA and Repair Times

This is where the difference becomes most critical. When your broadband fails, you are in a queue with every other residential and business customer. Openreach targets repairs within 1-2 working days, but there is no contractual obligation. We cover this in detail in our article on guaranteed uptime vs best-effort broadband.

A leased line comes with a comprehensive SLA that typically includes:

• 99.95% uptime guarantee — less than 4.4 hours of permitted downtime per year
• 4-6 hour repair time — an engineer will fix the fault within hours, not days
• 24/7/365 support — faults are addressed around the clock, including weekends and bank holidays
• Financial compensation — service credits if the provider misses their SLA targets

Cost Comparison

Broadband is significantly cheaper than a leased line. Here is a realistic comparison for Northern Ireland businesses:

• FTTC Broadband (80Mbps): £25-£45/month
• FTTP Broadband (300Mbps): £40-£60/month
• Leased Line (100Mbps): £200-£400/month (depending on location and contract length)
• Leased Line (1Gbps): £400-£800/month

The price difference is substantial, but the question is not "which is cheaper?" — it is "what does downtime cost your business?" If a day without internet costs your business £2,000 in lost productivity and sales, a leased line at £300/month is cheap insurance.

Installation and Lead Times

Broadband can typically be installed within 1-2 weeks. A leased line requires a dedicated fibre circuit to be provisioned, which takes 30-90 working days depending on whether fibre infrastructure already exists at your premises.

This longer lead time is worth planning for. At Drakos Systems, we recommend businesses start the leased line ordering process well in advance of when they need it — ideally when signing a new office lease or planning an expansion.

Which Is Right for Your Business?

Broadband is suitable when:

• You have fewer than 10 users with light internet usage
• Internet downtime is inconvenient but not business-critical
• You have a backup connection (4G failover, for example) for emergencies
• Budget is the primary concern

A leased line is essential when:

• You rely on VoIP, video conferencing, or cloud applications
• Downtime directly impacts revenue (retail, hospitality, professional services)
• You need guaranteed upload speeds for CCTV, backups, or hosted services
• You have 20+ users or bandwidth-intensive operations
• You need an SLA with guaranteed repair times

Many Belfast businesses find the ideal solution is a combination: a leased line as the primary connection with business broadband or 4G as a failover. This provides the reliability of a leased line with the safety net of a backup connection if the worst happens. Read more about what occurs when your business internet goes down.

Drakos Systems: Your Connectivity Partner

We supply both broadband and leased line connections to businesses across Northern Ireland. Our team will assess your requirements, survey your premises, and recommend the right solution — whether that is a simple broadband upgrade, a dedicated leased line, or a resilient multi-connection setup with Cisco or Ubiquiti networking equipment managing intelligent failover.