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What is a Private Leased Line?

Leased Line, What is a Private Leased Line?

A private leased line or Domestic Private Leased Circuit (DPLC) is a dedicated communication circuit that interconnects two or more LAN sites.

Leased Line, What is a Private Leased Line?

It acts as a dedicated private tunnel from one point to the other where data can continuously flow for a fixed monthly fee or rent, hence the name.

Leased lines are used to connect branches to company headquarter privately. They are typically run on fiber optic cables to provide large bandwidth and speed.

Leased line or managed WAN services reduce the complexity for IT departments to maintain connectivity between multiple sites.  

A domestic leased line will connect one or multiple sites located in Laos.

An International Private Leased Circuit (IPLC) or International Ethernet Private Line (IEPL) connect one or multiple sites situated in Laos to a remote site located overseas.

Important parameters when ordering a private leased line:


As with every data circuit, the most important parameter is the bandwidth available. Bandwitdh is the maximum amount of data transmitted over an internet connection in a given amount of time. Bandwidth is usually expressed in Mbps.

Contention Ratio

Contention ratio is the term used to for the number of users that are currently sharing data capacity. Contention ratio mostly applies to Internet capacity but some service providers may also decide to implement a contention ratio to their leased lines. Contention ratio allows service providers to oversubscribed their network hence increasing margins.

Leased Line, What is a Private Leased Line?

If you would like the service provider to allocate the full capacity to your circuit, you should ask a ‘non contended’ circuit which is equal to a contention ratio of 1:1.

Maximum Transmit Unit – MTU

The maximum transmission unit (MTU) is the size of the largest protocol data unit (PDU) that can be communicated in a single network layer transaction. When ordering a leased line, you should ensure that the MTU is 1500 which is the standard MTU for Ethernet frame. If you plan to use VLANs, you may also ask for an additional 4 bytes to pass the dot1q tag.

Leased Line, What is a Private Leased Line?

VLAN Transparent

A virtual local area network is a logical subnetwork that groups a collection of devices from different physical LANs. If you plan to carry multiple VLANs between your different sites, you should ensure that the circuit provided by the provider is “vlan transparent” ie. carry your VLAN tag across the link without any alteration.

Service Level Agreement – SLA

Service Level Agreement (SLA) is the service contract component between a service provider and customer. A SLA provides specific and measurable aspects related to service offerings. When it comes to leased line, the main parameter would be the service available (in % of availability per month), the maximum packet loss and the maximum latency on the link.


The availability of your circuit is the most important parameter. It is usually calculated over a month. Do not accept availability calculated over a year. The availability is usually displayed in %. The calculation is very simple:

Circuit Availability in % = [1 – (service downtime during the month in minutes)/(total minutes in a month)]*100

Example: your circuit was down for 2h35mn during the month of October. Service downtime is 155mn. In October, there are 31 days x 24 hours x 60mn = 44,640 minutes. Your circuit availability is 1 – 155/44640 = 99.65%

An acceptable SLA for a domestic leased line circuit starts at 99%. A good SLA would be 99.9%.

Packet Loss

Leased Line, What is a Private Leased Line?

Packet loss occurs when one or more packets of data traveling across a service provider network fail to reach their destination. Packet losses lead to network performance issues and service degradation hence should be included in a standard SLA contract.


Latency determines how fast the contents within a pipe can be transferred from the client router to the server and back. Excess of latency affects user experience. Latency and Jitter have a deep impact on video and VoIP applications. A standard SLA contract should also include the maximum latency accepted on the circuit.

Leased Line, What is a Private Leased Line?

Who are the main providers of Leased Lines in Laos?

The telecommunication providers that provide leased line services in Laos are Skytel, Lao Telecom, ETL and Unitel.

What about SD-WAN?

SD-WAN is a software-defined approach to managing the wide-area network, or WAN. Through a centralized interface, a cloud-delivered SD-WAN architecture allows companies to scale cloud-based applications across thousands of endpoints in the branch, campus, or SaaS and public cloud applications at distance. Source

SD-WAN is a new technology that sits on top of the leased line and internet services as well. SD-WAN allows enterprise customers to build a reliable and powerful WAN architecture that is agnostic of the underlying technology. Customers can decide to choose any type of connectivity such as leased line, dedicated Internet access (DIA) but also FTTH or even 4G cellular internet.

That being said, the quality of the underlying technology still has an impact on service performance. As such, it can still make sense to contract high-end leased line services underneath an SD-WAN architecture. SD-WAN architecture allows enterprise customers in Laos to enhance their leased line network with a cost-effective backup link such as fixed or mobile broadband.

Leased Line, What is a Private Leased Line?

ICT Companies such as GDMS offer SD-WAN services in Laos.

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