Dark fibre or wavelength: choosing your level of control

Start with the operating model

Dark fibre is an unlit fibre resource. The customer, or an appointed operator, supplies the optical transmission equipment. A wavelength service provides an optical transport channel over an operated network. Managed capacity is a broader commercial description: the interface and service layer must be specified in the proposal.

These choices create different responsibilities. Access to fibre does not, by itself, provide a working end-to-end service. Equipment, power, site access, maintenance arrangements and an engineered optical design still have to come together.

Compare the service boundary

Check the engineering inputs

ITU-T G.652 describes characteristics of single-mode optical fibre and cable. ITU-T G.694.1 defines the frequency grid used for dense wavelength-division multiplexing. These standards provide technical reference points; they do not establish that a particular fibre segment can support a proposed service.

Ask for the actual fibre specification, route length, attenuation measurements and connection details. For a customer-operated optical layer, the engineering team must assess the equipment against the complete path, including any regeneration or amplification requirements.

Define acceptance before ordering

A useful request gives both endpoint addresses, the required interface, the initial bandwidth and the expected growth. It also identifies who provides local access and cross-connects at each end. Describe the application and how it behaves during an interruption.

• Agree the measurement points and acceptance test method.
• State whether protection is required and what failure scenarios it covers.
• Separate installation, recurring service and site-related responsibilities.
• Record maintenance windows, escalation contacts and restoration arrangements.

Compare proposals using the same service boundary. A low monthly price is difficult to interpret when one offer includes local access and another stops at a carrier handoff.

Apply the choice to a cross-border route

A long corridor may combine different service models across its segments. A wavelength available between two cities does not establish that dark fibre can be leased over the same path. Start with the end-to-end requirement, then verify each underlying segment and interconnection.

For ADNET's Digital Silk Road initiative, all route and service options require individual technical and commercial confirmation. The map is a starting point for that conversation.