Capex vs Opex
As with any capital intensive project, when building broadband networks bridging the period between construction and customer revenue is critical to the viability of the project.
Options to limit the initial spend prior to revenue are attractive as it reduces the peak funding requirement for the project. Typically, this can be achieved by fully building out services to a service area limited by the available budget. Once customers arrive, a subsequent build phase can be undertaken to expand the service area.
An alternative approach is to defer components of the initial build that can be delivered in a timely and cost effective manner at the time a customer requests service. That is, trade capex for opex. This is observed with the common practice to not provision drops (aka leadins) during the initial build. This makes sense as it is a relatively quick job to install a drop and doesn’t require the mobilisation of a substantial workforce, nor permits, traffic management, etc.
Limiting the initial build to a point deeper into the network, however, say at a splitter cabinet for instance, would not be as effective as approach. Though it would likely save a lot of money during the initial capex phase, remobilising construction crews a second time would be very costly.
Microduct as Goldilocks?
An alternative approach utilizing airblown microduct potentially enables this second scenario though. By provisioning a network of microduct bundles fanning out from the splitter cabinet down to the customer locations, one can reduce splicing and defer the placement of optical equipment (ie: cables and splitters) below the cabinet until customer activation. Owing to the ease in blowing fibre through a well planned and installed microduct network, from a provisioning point of view, the drop can effectively be considered the path all the way back to the splitter cabinet.
Furthermore, modern installation techniques for microduct can be very efficient these days. Microtrenching for instance, is a technique where a very narrow trench to house the microduct is cut into the pavement slightly offset from where the road meets the curb. Depending on the machines used, the cut trench can range in width from around 0.75-inches to 2.25-inches and up to 16-inches deep, (which is typically above existing utilities).
In a single pass, the trench can be cut, the duct laid and the trench resealed - neat, clean and ready for road traffic. Compared to conventional methods, this an efficient and very cost effective process - a single crew can typically install up to 2,000 feet of microduct a day.
To learn more about microtrenching check out the nice explainer from the Fiber Broadband Association here.
Future proof
Installing a microduct network day one can also future proof your network and alleviate any concerns about the ability for your network to meet the ever increasing need for bandwidth into the future. By provisioning a physical “dumb” path (aka a microduct tube) to every potential end-point in your service area, you have flexibility on what to run through that path.
A common situation is how to deliver service to a newly built multidwelling unit comprising hundreds of apartments that was not planned for during the initial network rollout. With a dedicated microduct tube to the building location, you are able to blow in a high fibre count cable to meet even the most extreme demand profile, no problem (check out the Prysmian range for instance).
It starts with a good design
Incorporating microduct into your network planning day one will maximise the benefits discussed. Pozibl have a range of tools that are tailored to planning large scale deployments of microduct efficiently. They can be readily customised to suit your specific needs. It may be worth stating the obvious that a microduct network is buried, and hence an accurate record of the installed network is an imperative in order to operate the network effectively. The benefit of a good design is the provision of an accurate digital representation of the network that can be promoted to operational systems of record and that has all the information required.
A Pozibl microduct design incorporates:
- Efficient path routing (to minimise civils footprint)
- Guaranteed network architecture compliance
- Fully typed and annotated machine readable design outputs
- Friendly no-fuss problem resolution and technical advice
Lets see a Sample
Please take a look at the sample design generated for the township of Carmel-by-the-Sea - where (fun fact) the downtown has no street addresses! Nevertheless, design is still possible.
If you like what you see and would like to hear more, then get in touch via [email protected]