Choosing Between One Fast Line and Two Diverse Lines

With a fixed connectivity budget, many businesses face a choice: buy one large, fast connection, or split the budget across two smaller connections on diverse paths. The right answer depends on what hurts your business more — limited bandwidth or downtime.

Option 1: One fast line

You get maximum bandwidth and the simplest setup. Performance is excellent — until that single line fails. A fiber cut, equipment fault or provider issue takes the entire site offline.

Option 2: Two diverse lines

Each line has less bandwidth, but they travel different physical paths, ideally from different network nodes or providers. If one fails, the other carries traffic. In normal operation, both can be used at once through load balancing or SD-WAN, so total capacity is often similar.

The deciding factor: cost of downtime

Estimate what an hour of downtime costs: lost sales, idle staff, missed customer commitments and reputational damage. If a few hours of downtime a year would cost more than the bandwidth you give up, redundancy wins.

Hybrid approaches

• Primary leased line + business broadband backup: strong performance and affordable resilience.
• Primary leased line + 4G/5G backup: quick to deploy and independent of underground cables.
• Two leased lines from different providers: maximum resilience for critical sites.

Application priorities

Use routing policies to keep critical applications on the best available path and move less important traffic, such as backups, to the secondary line.

Plan for growth

Bandwidth can be upgraded later. Adding diversity after the fact is often harder, especially in buildings with limited entry points.

The bottom line

For most businesses, resilience delivers more value than raw speed. Design for continuity first, then add bandwidth as your needs grow.

Learn more about Dedicated Internet Access (DIA) from UbiFi, or talk to our team.