# IEPL vs IPLC: the site definitions

IPLC is legacy time-division private capacity carried over SDH or OTN; IEPL is Ethernet private capacity. Both give point-to-point connectivity between your sites, but they hand off different interfaces and suit different installed equipment. This site uses the two words in exactly that sense.

- IPLC = legacy SDH/OTN private capacity between countries; IEPL = Ethernet private capacity between countries.

- New builds choose Ethernet; installed IPLC runs its course.

- IPLC is a Layer 1 circuit; IEPL is a Layer 2 Ethernet service. The difference shows up at the demarcation point.

- Private capacity is not encrypted capacity. Separation from the public internet is not the same as encryption.

## The definitions

An [international private leased circuit](/en/resources/glossary/iplc/) (IPLC) is the SDH/OTN-era private line: time-division capacity between two countries, sold at fixed rates such as E1, STM-1, STM-4 or STM-16. It behaves like a transparent pipe. The customer hands off a framed signal at each end, and the provider carries the bits without interpreting the Layer 2 protocol inside. An [international Ethernet private line](/en/resources/glossary/iepl/) (IEPL) carries Ethernet frames privately instead, with a port-based service (EPL) or a VLAN-based service (EVPL) as defined in ITU-T G.8011. The customer hands off an Ethernet interface, usually 1000BASE-LX or 10GBASE-LR, and the provider forwards frames between the two sites.
The practical difference is where the provider's responsibility ends. With IPLC, the demarcation is a time-division interface and the customer's router owns everything above it. With IEPL, the demarcation is an Ethernet port and the provider is already forwarding frames, so VLAN handling, MTU and Ethernet OAM become part of the service conversation. Neither term says anything about the underlying fiber; both can run over the same optical network.

### Where the handoff sits on a private line

A schematic, not a map: local loop, international segment, border handoff and domestic leg. IPLC hands off a time-division signal; IEPL hands off Ethernet frames.

Alt: Four segments in order: local loop, international transit, border handoff and domestic leg, with the handoff marked.

The diagram shows the four segments of a cross-border private line and no real geography. The local loop connects each site to the provider's point of presence. The international segment carries the circuit between countries. The border handoff is the demarcation where the service definition and the interface type are fixed. The domestic leg reaches the far-end site. IPLC and IEPL can use the same fiber and the same international segment; they differ at the handoff and in what the provider forwards.

| Item | Value | Note |
| --- | --- | --- |
| First state · 1 | Local loop |  |
| First state · 2 | International transit |  |
| First state · 3 | Border / handoff |  |
| First state · 4 | Domestic leg |  |

Source: ITU-T G.8011: Ethernet service characteristics (https://www.itu.int/rec/T-REC-G.8011)

### The handoff decides the service

|  | IPLC | IEPL (EPL) | IEPL (EVPL) |
| --- | --- | --- | --- |
| Interface at the demarcation | E1 or STM-N | An Ethernet port, whole port | An Ethernet port, shared by VLAN |
| What the provider forwards | A framed time-division signal | Ethernet frames | Ethernet frames by VLAN |
| What your router owns | Everything above the framed signal | IP and above | IP and above, plus the VLAN plan |
| Fit | Installed TDM equipment and fixed-rate applications | New builds between two sites | Several sites or services sharing a port |

ITU-T G.8011 defines Ethernet private-line services; G.707 and G.709 define SDH and OTN transport.

## Choosing

Greenfield designs take IEPL. Ethernet is what applications and routers speak natively, the port rates scale in useful steps, and the service is easier to integrate with a modern WAN. Installed IPLC bases stay until their contracts and hardware cycles end, because replacing a working circuit has a migration cost that the acronym does not capture. The decision point is usually the contract renewal or the end of support for the SDH equipment, not a preference for newer technology. When a site already has an E1 router and a working circuit, the cheapest next step may be to keep it for another term.
Some requirements still favor a TDM handoff: an application that needs a deterministic fixed-rate pipe, an installed PBX or legacy device with an E1 interface, or a contract that specifies a traditional private line. Those are exceptions. For most data traffic between offices, plants and data centers, Ethernet is the better fit.

## What the handoff looks like

At the customer end, IPLC usually arrives as an E1 (2.048 Mbps) or an STM-N interface, terminated on a router or a multiplexer. IEPL usually arrives as an Ethernet port on a switch or router, with a copper or optical interface and a defined speed. In both cases there is a demarcation point, often a network terminating unit provided by the carrier at its [point of presence](/en/resources/glossary/pop/), and the customer is responsible for the cabling and equipment beyond it. Ask which side owns the NTU, what the connector type is, and whether a cross-connect inside the building is included.
The handoff decides more than the cable. An E1 handoff caps the circuit at 2 Mbps per port, so growth means adding ports or moving to a higher TDM rate. An Ethernet handoff can be 10 Mbps, 100 Mbps, 1 Gbps or 10 Gbps on the same fiber, which makes upgrades simpler. It also changes the failure diagnosis: with Ethernet you can test frames, VLANs and OAM; with TDM you test the framed signal and the bit errors.

### What to check in a quote

- [ ] Ask whether the service is EPL or EVPL. — EPL gives you the whole port. EVPL shares a port across VLANs and needs a VLAN plan.
- [ ] Ask for the committed rate, the burst behavior and the port speed. — A 1 Gbps port does not mean 1 Gbps of committed capacity.
- [ ] Ask for the protection option and whether the backup path is physically diverse.
- [ ] Ask for the MTU and whether jumbo frames are supported.
- [ ] Ask how the circuit is tested at turn-up and what the acceptance criteria are.
- [ ] Ask about the local loop at both ends, the term and the end-of-term process.
- [ ] Ask whether the circuit can be upgraded in place or needs a new port and lead time.

If the circuit crosses into mainland China, scope cross-border approval and filing with counsel. This page is not legal advice.

A private line removes some variability. It does not remove the fiber floor.

[Open the tool](/en/tools/fiber-latency/?src=learn-iepl-vs-iplc&scenario=mexico-shanghai&pathFactor=1.5)

## Why the words matter

The two terms are often used as if they were synonyms, and that causes real procurement mistakes. A quote that says private line without saying which one can be quoted against a different handoff, a different protection level or a different port speed. A customer expecting an Ethernet port may receive an E1 interface and need a new router. A customer expecting a transparent Layer 1 pipe may receive an EVPL service that polices VLANs.
The site uses IPLC for the legacy TDM circuit and IEPL for the Ethernet service, and a quote should do the same. If a provider uses the words differently, ask for the handoff and the service definition in writing. That written definition matters more than the label. The [China connectivity explainer](/en/resources/learn/china-connectivity-options-latam/) compares private lines with transit and access, and the [premium vs standard comparison](/en/resources/compare/china-transit-premium-vs-standard/) covers the transit side.

## Common mistakes

The first mistake is treating IEPL as an internet service. It is point-to-point capacity, not an on-ramp. The second is confusing EPL and EVPL and assuming the provider will carry any VLAN you send. The third is ignoring MTU: a circuit that passes 1500-byte frames may drop jumbo frames, and the application sees it as intermittent loss. The fourth is assuming protection is included when the quote only has a single path. The fifth is comparing a 100 Mbps committed rate with a 1 Gbps port speed. The sixth is assuming private means encrypted; if the data needs encryption, run it end to end. The seventh is forgetting the local loop, which can be the longest lead time in the order.

### Check what you learned

**A quote says private line but not which one. What is the first question?**

Ask for the handoff and the service definition. An E1 or STM-N handoff means IPLC; an Ethernet port means IEPL, and you still need to know whether it is EPL or EVPL.

**The port is 1 Gbps. Does that mean 1 Gbps of committed capacity?**

No. The port speed is the interface rate. Ask for the committed rate, the burst behavior and the measurement method in the same quote.

**Does a private line encrypt the traffic?**

No. Private capacity is separated from the public internet; it is not encrypted by default. If the data needs encryption, run it end to end.

## FAQ

**Is IEPL always better?**

For new builds, yes in practice. For installed bases, the migration cost decides, not the acronym.

**Can IPLC run at very high rates?**

TDM rates go up to STM-256 in ITU-T G.707, but high-rate TDM is uncommon in new builds. Ask what the provider can actually deliver on your route.

**Is IEPL encrypted?**

No. It is private capacity, separated from the public internet, but separation is not encryption. Encrypt the traffic end to end if it needs it.

**Does IEPL give a fixed latency?**

No. It gives a defined path, which removes some variability, but distance sets the floor. Ask for measured figures and the terms that apply to your city pair.

**What is the difference between EPL and EVPL?**

EPL gives you the whole Ethernet port. EVPL shares a port across VLANs, so you need a VLAN plan and the provider polices it. Both are IEPL services under ITU-T G.8011.

**Can we migrate from IPLC to IEPL without downtime?**

Plan a parallel service and a maintenance window. The new circuit is tested before the old one is disconnected, and the router configuration changes at a time you control.

## Sources

- [ITU-T G.8011: Ethernet service characteristics](https://www.itu.int/rec/T-REC-G.8011) — Accessed: 2026-10-19
- [ITU-T G.709: interfaces for the optical transport network (OTN)](https://www.itu.int/rec/T-REC-G.709) — Accessed: 2026-10-19
- [ITU-T G.707: network node interface for the synchronous digital hierarchy (SDH)](https://www.itu.int/rec/T-REC-G.707) — Accessed: 2026-10-19
- [ITU-T G.652: characteristics of a single-mode optical fibre and cable](https://www.itu.int/rec/T-REC-G.652) — Accessed: 2026-10-19

Updated: 2026-10-19