An Ethernet Private Line (EPL) is a point-to-point Carrier Ethernet service that connects two locations at Layer 2, so they behave as if joined by one long Ethernet cable. It is port-based: the circuit uses a dedicated port and hand-off at each end, and your Ethernet frames pass between the sites largely as sent, without the carrier routing them over the public internet. EPL is one of the E-Line services defined by MEF, the Carrier Ethernet standards body, and is the modern equivalent of a traditional leased line.
At a glance
- EPL links exactly two sites with a private, point-to-point Ethernet circuit at a committed bandwidth.
- It is port-based and largely transparent: one circuit per port, with your VLANs and much of your Layer 2 traffic passed through as sent.
- It runs over the carrier’s own network, not the public internet, but is not encrypted unless you add encryption.
- Service levels for availability, latency, jitter and packet loss depend on the provider and contract.
- Availability, price and installation time depend heavily on whether the carrier has fiber into both buildings.
What problem it solves
Some traffic between two sites needs more predictability than the internet offers: storage replication between a headquarters and a data center, connections between campus buildings, voice and video between offices, or large file transfers in media and engineering. Over the internet, path, latency and congestion vary, and performance is not under any one provider’s control.
An EPL gives two sites a private connection on one carrier’s network with committed bandwidth and a predictable path. Because it works at Layer 2, both ends can be on the same network segment, and IT can extend VLANs and run its own routing without building VPN tunnels. It is a simple, well-understood building block for linking a few key locations.
How it works
Access. At each site, the carrier hands off an Ethernet port, usually over fiber, to your switch or router. Where the carrier isn’t already in the building, a new fiber build or a partner’s access circuit may be needed.
Transport. Between the sites, the carrier carries your traffic over its own network, which may use metro Ethernet, MPLS or optical transport depending on distance and design. Your traffic is kept separate from other customers’ traffic.
Port-based service. All traffic arriving on the port belongs to the one circuit. That makes EPL simple and transparent: the carrier doesn’t need to know your VLAN numbers, and many Layer 2 control protocols can pass through, though support for specific protocols and frame sizes should be checked.
Bandwidth and service levels. You buy a committed rate, which may be lower than the port speed, with service levels that vary by provider and contract. Protection against fiber cuts depends on whether the carrier’s path is protected or whether you buy a second, diverse circuit.
When it matters for buyers
- When linking a small number of critical sites. Headquarters to data center, data center to disaster recovery site, or between campus buildings.
- When replacing legacy circuits. Many carriers are retiring older copper and TDM services such as T1s, and EPL is a common replacement for point-to-point links.
- When designing a hub-and-spoke network. Many EPLs into one hub use many ports; a VLAN-aware service or MPLS may fit better.
- When regulated data crosses the link. Private transport isn’t encryption; add your own if requirements call for it.
- When resilience matters. One circuit is a single path. Ask about path protection or buy a diverse second circuit, possibly from another carrier.
For multi-site and international designs that combine EPL with other services, see our global WAN services overview.
Questions to ask vendors
- Are you on-net at both locations, and if not, who provides the access and what build is needed?
- What committed bandwidth and port speeds are available, and can bandwidth be raised without new equipment?
- What availability, latency, jitter and packet loss commitments are in the SLA, and what are the remedies?
- Is the path protected, and can you provide a physically diverse second route?
- Which Layer 2 protocols, VLANs and frame sizes pass through transparently?
- What is the installation interval, and what happens if it slips?
- What monitoring and reporting do we get on circuit performance?
How it differs from EVPL
An Ethernet Virtual Private Line (EVPL) is also a point-to-point E-Line service, but it is VLAN-aware rather than port-based. The provider assigns traffic to circuits by VLAN or other rules, so several circuits can share one port, which suits a hub site linking to many branches. EPL dedicates the port to one circuit and passes traffic largely as sent, which makes it simpler and more transparent for a single link. EPL also differs from a wavelength service, which carries traffic over a dedicated optical channel, usually at higher capacities, and from dedicated internet access (DIA), which connects a site to the internet rather than to another of your sites. Many WANs combine EPL with DIA and an SD-WAN overlay.
Problems this helps with
- Need a private, predictable link between headquarters and a data center
- Replicating large amounts of data between two sites over the internet is too slow or inconsistent
- Want two locations to behave like one network without routing across the internet
- Replacing an old leased line or T1 between buildings
