FAQ's & Guides

Telecommunication Network Demarcation Point: Explained

October 30, 2018

In telecommunications networks, the demarcation point (often abbreviated to DEMARC and otherwise known as boundary point or network boundary point) is the physical point at which the public switched telephone network ends and the private network of the customer begins. In most cases it is where the cabling physically enters the building.

The demarcation point forms a dividing-line between those that are responsible for installation and maintenance of wiring and equipment (the customer/subscriber or the telephone operator/provider).

The demarcation point can vary depending on the country you are in and has changed over time.

Residential demarcation point

For residential buildings the demarcation point will be either at the first socket or a boundary box located on an external wall. Externally, the providers wiring runs to the building (either overhead or underground). The wires are then switched at the DEMARC point.

Business/Organisation demarcation point

Generally, if your business subscribes to receive internet services through a local provider, they will install a demarcation point at your business. This is usually a grey box mounted on the outside of the building or possibly within a basement at the main distribution frame (MDF). Externally, the providers wiring runs to the building (either overhead or underground). The wires are then switched at the DEMARC point.

For some services, such as ISDN, there is a network boundary device (NBD) or network termination unit (NTU) also. The carrier’s responsibility runs from the exchange to the boundary point and, if applicable, this includes the NTU. The wiring remains the customers responsibility.

Why it is important to know where your demarcation point is

Understanding the location of your demarcation point means that in the case of a fault in your service, you can guide a technician to investigate.

If you experience a fault in your telecommunications network and you are in an office building, the chances that the fault is within the internal wiring is much higher.

The service providers responsibility ends at the demarcation point, so whether it is an office or home network, if you find the fault within the B side (customer premises) then it is up to you to organise repairs.

Specialised Demarcation Equipment

Depending on the scale and complexity of the customers network, sometimes specialist DEMARC products are used to link the provider with the customer.

Theses products are used to provide advanced functionality at the demarcation point and allow both the customer and provider to benefit from a number of things, including:

  • Protection & Security: Layers of protection can be added to the network at the demarcation point through various security protocols
  • Fault Propagation: Link failures can be detected and traffic can be rerouted accordingly. Also, failure messages can be sent in either direction on the network (customer and provider)
  • Management: In-band and out-of-band management features can be accessed via demarcation equipment ports

Examples of these types of demarcation products include:

Atrica (Nokia Siemens Networks) A-210 Optical Ethernet Edge Switch

Atrica (Nokia Siemens Networks) A-100 Optical Ethernet Edge Switch

To find out more about these products, simply click the links above.

Having a better understanding of what a demarcation point is will help you to save time if a fault is found in your network. It will also allow you to better consider products that can be used to improve functionality and security within your network.

Carritech support a wide range of telecommunication products, including demarcation switches such as those listed above. If you are interested in finding out more about how we can help to support your network, with supply, repair and refurbishment of these types of equipment, contact us today.

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