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A leased line is a private, dedicated connection between two points. A VPN (virtual private network) is a secure tunnel that runs over a shared network, usually the internet. Choose a leased line when you need guaranteed performance and the strongest security. Choose a VPN when you need flexibility and a lower cost across many sites or remote users.
Leased line vs VPN
| Feature | Leased line | VPN |
|---|---|---|
| Connection type | Dedicated, private circuit | Encrypted tunnel over shared infrastructure, or over a carrier's private network |
| Security | Very high. Traffic doesn't cross the public internet | Depends on the type. Internet VPNs rely on encryption over the public internet, carrier IP VPNs run on a private network |
| Performance | Fixed bandwidth, no contention and consistent latency | Internet VPNs vary with congestion. IP VPNs are more consistent |
| Reliability and SLA | Backed by a service level agreement (SLA) | Varies by VPN type and provider |
| Cost | Higher, because it uses dedicated infrastructure | Lower, especially for internet VPNs |
| Multiple sites | Point to point, so each extra site needs its own circuit | Many sites and remote users on one network |
What's a leased line?
A leased line is a dedicated connection that gives your business a private, fixed-bandwidth link. Nobody else shares it, so your traffic doesn't compete for capacity the way it does on broadband. You get symmetric speeds, consistent performance and an SLA that backs uptime.
Many businesses use a leased line for internet access, often called dedicated internet access (DIA). Read our guide to what leased lines are, or explore Colt's leased line service.
What's a VPN?
A VPN builds a private route across a network you don't fully control. It works in three steps: tunnelling, encryption and authentication. The tunnel links the two ends, encryption hides your data and authentication confirms both sides are who they say they are.
An internet VPN runs over the public internet. It's the cheapest and quickest to set up. But performance depends on how busy the internet is, and it's the least private option.
An IP VPN runs over a carrier's private multiprotocol label switching (MPLS) network instead of the public internet. You get more consistent performance and stronger security than an internet VPN, at a higher cost.
Which should you choose?
It comes down to security, performance and how many sites you need to connect.
- Choose a leased line if you handle sensitive data, run latency-sensitive applications such as trading or real-time video, or need guaranteed bandwidth between two key locations
- Choose an internet VPN if you need low-cost access for remote workers or small sites
- Choose an IP VPN if you need private, predictable connectivity across many sites and a leased line for each would cost too much
- Combine them if you have both needs. Many networks run leased lines between core sites and VPNs for everything else
Need to link several sites privately? Colt Ethernet services connect your sites over our own infrastructure, including Ethernet VPN for any-to-any connectivity.
What about SD WAN and SASE?
Many businesses now add SD WAN (software-defined wide area network) and SASE (secure access service edge) on top of their connections. They don't replace the connection underneath. SD WAN steers traffic across leased lines, VPNs and broadband to pick the best path for each application. SASE adds cloud-delivered security. A dependable leased line still gives both a strong foundation.
Frequently asked questions
What's the difference between a leased line and a VPN?
A leased line is a dedicated, private circuit between two points. A VPN is an encrypted tunnel across a shared network. A leased line gives you guaranteed bandwidth and the highest security. A VPN gives you flexibility and a lower cost.
Is a leased line more secure than a VPN?
Generally, yes. A leased line doesn't cross the public internet and only your business uses it. A VPN encrypts your traffic, but an internet VPN still travels over shared infrastructure. An IP VPN sits in between.
What's the difference between a leased line and MPLS?
MPLS is a technology carriers use to build private networks, including IP VPNs. A leased line is a dedicated circuit between two points. An MPLS IP VPN connects many sites on one private network, while a leased line connects two.
How does a leased line compare with SD WAN?
They do different jobs. A leased line is the connection. SD WAN is the software that manages traffic across one or more connections, including leased lines. Many businesses use both.
Can I use a leased line and a VPN together?
Yes. Many businesses run a leased line between key sites and use VPNs for remote workers and smaller locations. You can also run a VPN over a leased line to add encryption.
How much does a leased line cost?
It depends on bandwidth, location and contract length. A leased line costs more than a VPN because it uses dedicated infrastructure. Check availability and get a quote with Colt Connect.
