The digital divide is an issue that has been evident since the dawn of the internet; some have had quick access while many others haven’t. In fact, the World Economic Forum recently reported that although 70% of homes in the European Union had high-speed internet connections in 2021, in rural areas it was only 37%, which is a challenge we need to address, says Steve Alexander, chief technology officer, Ciena Corporation.
We’d think that by now we would have solved the issue but alas, it continues to escape us, with the digital divide becoming an increasing issue as metropolitan hubs gain access to hyper speed broadband while their rural counterparts don’t. Ultimately, the reason we have a divide in the first place is due to the “last mile”.
In networking parlance, the last mile is the final connection between the service provider and the customer. Much like the branches and stems carrying the leaves on a tree, they may be quite a distance from the high-capacity trunks and often represent the ultimate capacity bottleneck that a user may experience. Even when network providers have rolled out thousands of miles of trunk fibres to various points of presence in an area, the truly hard part begins: connecting each home to the internet.
This is where the divide begins, because for a service provider it’s simply more feasible to connect some homes than others.
If we look at homes in European cities, there is usually a large population to draw on, with many people and businesses nearby wanting to access the network. Economically, service providers will see a better Return on Investment (ROI) from a network roll-out if it has a larger base of customers to leverage it.
But in a rural area the value proposition for service providers begins to plummet. Not only do they need to roll fibre to the town, but to each home in a lightly populated region in which customers are fewer. For service providers, the expense and speed of the rollout combined with the limited number of customers hinders ROI significantly with many low-density areas having zero or negative ROIs. However, this means in more rural places we start to see citizens making do with slow and spotty internet or sometimes no internet at all forced to go to cafes or libraries to find stable and quick connections. Dependability and availability weren’t the only concerns, however, with cost also an issue for many residents.
For towns across Europe with similar issues, they may need to take it upon themselves to bring access to their communities. And many now see the digital divide as something they need to bridge, even if they must do the bridging.
But how can they do this without bankrupting the town? If it’s too expensive for service providers, how is a town able to do this now? Well, an interesting technology was deployed to provide the fibre to every home, one that has been around for years but has recently boomed in popularity: Passive Optical Networking.
Passive Optical Networks (PONs) are not anything new; in short, a PON is an architecture in which a single optical fibre serves multiple endpoints by using passive fibre optic splitters to divide the fibre bandwidth. There is a device known as an Optical Line Terminal (OLT) at the service provider end and an Optical Network Unit (ONU) at each customer location. Between the OLT and the ONUs is nothing but types of glass. In plain terms, the technology makes it possible for a single fibre-optic cable to provide very-high-speed broadband access to multiple users.
If PON is that effective, and it’s been around for years, then why are we still having issues connecting the last mile access in rural areas?
Traditionally, over short distances PON has been effective at enabling high-speed access to many. It has a completely passive Outside Plant (OSP) that eliminates active electronics from the OSP which are often fault-generating points, thereby simplifying network operation.
However, over long feeders, the OSP/Optical Distribution Network (ODN) cost for the traditional PON architecture increases rapidly. Also, optical splitting power loss over distances limits system reach.
But the technology has evolved to ensure that PON is now a viable option for last mile rollouts.
Traditionally, PON applications have been supported by large, purpose-built OLT chassis deployments. But an evolution in hardware design has led to the development of micro-OLTs which are pluggable that combine the OLT laser with an embedded Ethernet MAC and fit neatly into a 10G SFP+ optical transceiver routing and switching port making life much simpler and cost-effective for network operators.
In addition, PON applications have typically been symmetrically limited to 1Gb/s for up to 32 customers. But adding 10G PON capable IP and Ethernet platforms has allowed the likes of Dryden and other last mile network providers to deliver 10x more bandwidth and provide many higher-bandwidth applications both now and into the future.
Have we solved the last mile conundrum? Well, it’s close. Rural areas can now see a light at the end of the last mile which may bring them up to speed with their metropolitan counterparts, with PON and other evolving technologies stepping in to bridge the digital divide.
The author is Steve Alexander, chief technology officer, Ciena Corporation
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