How fast is fibre?
Fibre vs. Other Technologies
How does fibre compare with Wireless, DSL, Cable, Satellite, and BPL?
Wireless
Wireless technology holds great promise for the delivery of broadband services within homes and buildings. Already in widespread use, 802.11b and 802.11g networks solve the wiring problems for homes and offices that do not wish to retrofit. Emerging standards such as WiMAX (802.16) offer faster transmission speeds, cover larger distances, penetrate buildings better, and are not subject to line-of-sight restrictions as were earlier wireless standards. Compared with other wireless technologies such as G3, WiMAX operates in the free part of the radio spectrum and requires fewer base stations to operate. These types of advances make wireless more and more appealing for an increasing number of applications.
Despite these advances, wireless is not an option as the core technology for a project like the NanoFibre network. Wireless may play a role in serving areas waiting to be constructed, but wireless has limitations that make it unsuitable for a truly scalable, open-access network. Ultimately, to be effective, wireless must eventually tie in to a fibre infrastructure.
As a shared technology, wireless does not offer dedicated connections. Bandwidth is shared among all users within the distribution area—the more users at any given time, the less bandwidth per user. Furthermore, the capacity of wireless is limited: with potential maximum capacities of 90 Mbps, there is no possible way for wireless technology to offer every home in a dedicated 100 Mbps connection, let alone future 1 Gbps connections for businesses. Other issues such as susceptibility to signal theft and potential for interference make wireless an undesirable technology for data-sensitive or mission-critical business use.
In addition, though wireless might be able to provide adequate Internet access for sections of a community, the inability of wireless to distribute multiple, competing services, such as video programming, in a ubiquitous manner make it unsuitable for emerging converged technologies. It also does not satisfy NanoFibre's goal to provide a single infrastructure open to multiple competing providers.
Digital Subscriber Lines (DSL)
DSL technology is a convenient way for telephone subscribers to get better-than-dial-up speeds over their existing telephone lines. By piggy-backing a high frequency data signal over voice transmission lines, homes can receive asymmetrical "little broadband" (between 256Kbps and 3Mbps download) without having to install any new wiring.
Unlike cable or wireless, DSL connections are dedicated, not shared. That means that rather than sharing a stated capacity with several households, all of DSL's stated capacity is potentially available for the subscriber at all times.
Many homes in the Columbia Valley do not have access to DSL technology. The quality of wiring in certain areas may be inadequate to support a DSL signal, and a building's distance from the telephone company's central office precludes many homes from receiving DSL.
Telephone companies recognize the limits of copper. While incremental increases in DSL technology are likely, those increases will never solve increasing broadband needs. Fiber will provide what DSL and copper-based telecommunications will never be able to.
Cable Networks
Because a significant number of homes in any given community already have coaxial cable deployed, cable is often viewed as the most viable solution to delivering broadband services to homes and businesses. However, cable has significant limitations that make it unsuitable for NanoFibe’s open access network.
Cable systems connect numerous households to a shared signal distribution point, so everyone connected to that point actually shares the stated cable capacity (usually 3-5 Mbps). As more people use their cable modems simultaneously, less bandwidth is available for everyone on that connection, so cable modem users frequently get far less bandwidth than the stated capacity.
Because the topology and architecture of cable networks is a "bus topology" at the edge, bandwidth is shared among all users on the bus. In a typical cable split, hundreds of users may share the allocated bandwidth, meaning that no one user gets the full bandwidth unless he should happen to be the only one on the system at a particular time. In periods of heavy use by multiple users, traffic bogs the system down and available bandwidth shrinks correspondingly, causing lags and delays in connections. This may be merely an annoyance for home users, but it represents a serious drawback for business users.
Additionally, cable’s bandwidth claims are for downstream traffic only. Upstream traffic on a cable system is limited to approximately 10% of the total maximum capacity of the system, making the technology unsuitable for interactive services and applications or for businesses and residents requiring significant data transfer from their location to another.
Another problem with cable technology is its susceptibility to Radio Frequency Interference (RFI) and Electro Magnetic Interference (EMI): as a copper based medium, cable can be affected by household appliances, electrical storms, and other sources of interference. Additionally, as convergence becomes increasingly widespread in integrating technologies, cable systems will find themselves unable to support them. Add to those issues the well-known problems regarding the frequency with which cable systems experience outages, and it becomes clear that the ability of cable to deliver carrier class service makes it unsuitable.
Satellite and Microwave Broadband
Satellite and Microwave technologies are wireless technologies but differ from the more generally understood definition of wireless.
Microwave transmissions are possible on a line of sight basis: any object that comes between the transmitting tower and the receiver has the potential to interrupt the signal because, unlike other lower frequency transmissions (radio, TV, etc.), microwaves can not pass through buildings or even dense vegetation.
Microwave transmissions also suffer a form of attenuation and therefore have distance limitations. For microwaves, however, this limit is not fixed—it can vary based on something called “atmospheric path loss.” On a clear day with low humidity, when path conditions are optimal, a low power signal from a microwave tower can travel up to 25 kilometers. However, with atmospheric interference, as during a heavy rainstorm, the same signal, transmitted at the same power level, may travel only two or three kilometers.
Satellites are unsuitable for interactive applications because they typically transmit in one direction only: end users (such as DBS TV program consumers) can receive broadband transmissions, but they are unable to send signals directly back to the satellite. To do that, end users would need additional equipment, and there would be spectrum issues to address. As a result, applications and services requiring upstream transmission flows, such as sending requests to the internet to load a page, interactive gaming, and duplexed voice communication, rely on an additional source of connectivity (such as a copper connection, frequently called “telco return”) to complete the upstream transmission.
Because of the distance from the earth, signals from GEO satellites suffer from latency. In voice applications, this is manifest as the delay between the time the speaker finishes speaking and the listener hears the voice. A similar phenomenon affects other services and applications as well. This makes them unsuitable for interactive services.
As with all wireless transmissions, satellite and microwave technologies, in themselves, cannot offer security. Because the signals are sent through the air, anybody with the correct equipment can intercept wireless signals. While it is true that most transmissions will be encrypted, there is still a level of security missing from wireless transmissions that exists in other technologies.
Broadband Over Power Lines (BPL)
Much excitement has been generated over the possibility of providing broadband connections through the electrical wiring currently in homes and businesses. By simply plugging a special modem into any electrical outlet in your home, you would have internet access. The great advantage of this type of delivery is that no new infrastructure need be deployed; electrical power lines are ubiquitous. Other advantages include symmetrical upload and download speeds, and potentially cheaper pricing than DSL or cable.
While the concept is intriguing, the reality is that BPL has several problems because it attempts to adapt the copper power infrastructure to a function for which it was never intended. Inherently, the copper lines for electrical power suffer the same limitations copper telephone lines suffer: signal-to-noise tolerances limit the bandwidth and the distance signals can travel. Feedpoints and repeaters can be installed on the powerlines, but the scalability of BPL is limited.
Another significant problem with BPL is typical for all copper-based transmission: signals leak out of the wires. This leakage is even more pronounced at the frequencies at which BPL would operate. The leaked electromagnetic radiation interferes with amateur radio transmissions, and can, at different frequencies, interfere with other critical radio signals. And the fact that signals "leak" at all potentially compromises the security of highly sensitive data transmissions.
Some communities have had limited success with BPL deployments. Manassas, VA was the first US community to deploy BPL and plans to expand its service. In other areas it has failed. In Cedar Rapids, IA, a BPL pilot project was shut down because of radiating signals, and in Singapore two years of BPL development efforts have been scrapped because the technology was very labor intensive and suffered from frequent service calls and outages. For these and other reasons, BPL has been banned in multiple countries (Japan, Germany, and others). Ultimately, BPL is unsuitable to achieve the goals upon which NanoFibre is founded.