Q) What is dark fiber?
Dark Fiber is optical fiber, dedicated to a single customer, where the customer is responsible for attaching the telecommunications equipment and lasers to “light” the fiber. Dark fiber provides customers with flexibility, security, scalability, and reliability to their networks.
By providing their own equipment, customers are able to manage and scale to their own bandwidth requirements. Dark fiber allows the customer to consolidate various services across their network including voice, video, and data.
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Q) What equipment do I need to light up dark fiber?
With dark fiber, simple laser devices, called transceivers, are all that is required to light the fiber. These devices will work with SONET, ATM and Ethernet devices at either end of the fiber connection. With these networks there are only 3 things that can go wrong with dark fiber - the source transceiver, the destination transceiver or the fiber itself.
Transceivers for Ethernet data can provide a signal up to 120 km. The following are typical distances for Ethernet transceivers:
- Fast Ethernet (100 Mbps) transceivers can provide a signal up to 100 km
- Gigabit Ethernet transceivers will provide a signal up to 80km
Most Gigabit Ethernet equipment manufacturers include long haul lasers, which also can be directly attached to the dark fiber.
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Q) What is an IRU?
An IRU is an Indefeasible Right to Use the fiber. Most companies who offer dark fiber grant IRUs to the fiber. For regulatory reasons, generally only licensed carriers are allowed access to support structures and municipal rights of way. Rather than selling title to the fiber, the fiber contractors grant an IRU. An IRU can be used as collateral, sold or traded and otherwise treated like a physically owned asset.
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Q) How reliable is dark fiber?
Dark fiber can be more reliable than traditional telecommunication services, particularly if the customer deploys a diverse or redundant dark fiber route.
Dark fiber is a very simple technology. It is often referred to as being technologically neutral. Sections of dark fiber can be fused together so that one continuous strand exists between the customer and the ultimate destination. As such, the big advantage of dark fiber is that no active devices are required in the fiber path. Since there are no active devices, dark fiber in many cases can be more reliable than a traditional managed service. Traditional managed services usually have a myriad of devices in the network path such as SONET multiplexers, Add/Drop multiplexers, ATM switches, routers, etc. Each one of these devices is susceptible to failure, which is why traditional carriers have to deploy complex networks and systems to insure reliability and redundancy.
Many customers assume that because the carriers deploy SONET rings they have a reliable network. In fact, SONET rings are generally only deployed between carrier central offices. Most customers today, except in exceptional circumstances, only have one unprotected link to their nearest central office. This is the single weakest link in their network.
For the greatest reliability, many customers will install 2 separate dark fiber links to 2 separate service providers.
Because fiber has a greater tensile strength than copper or even steel, it is less susceptible breaks from wind or snow loads.
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Q) Does dark fiber increase my network management costs and complexity?
Network cost and complexity is significantly reduced with dark fiber in a number of ways:
- Dark fiber has no active devices in the path as in a typical carrier network, therefore are fewer devices to manage and less thing that are likely to go wrong.
- Repair and maintenance of the fiber is generally included in the service contract from Sunesys. Because Sunesys installed the fiber in the first place, it has the equipment, material, and know how to restore service quickly.
- Dark fiber allows organization to centralize servers and/or out source many different functions such as web hosting, server management, etc.
A fiber network allows large enterprise customers, universities and schools to essentially extend their in house LANs across the wide area. Because there is no effective cost to bandwidth with dark fiber the long distance LAN can be still run at native speeds with no performance degradation to the end user. It is therefore very simple to relocate a server to a distant location where previously it required close proximity because of LAN performance issues.
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Q) What about moves, adds, changes and fiber relocation services?
Moves, adds, and changes are completed by Sunesys at the request of the customer or as a result of road or other construction or repair. Moves, adds and changes that are the result of construction (outside of the customer’s doing) are included as part of the fiber maintenance contract. Moves, adds and changes that are performed at the request of the customer will have costs associated with them that vary based on the amount of work to be performed.
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Q) Is fiber the same fiber used by the carriers?
Yes. In most cases for metropolitan and long haul fiber the most common of fiber by carriers is Single Mode Fiber (SMF-28). This is usually adequate for most fiber installations. For particularly long spans or long distances, specialty Non-Zero Dispersion Shifted Fibers (NZDSF) are used. But given the cost difference, single mode fiber is generally the fiber of choice for most fiber installations.
All splices are performed with an industry-accepted fusion splicing machine and the customer is provided with testing documentation reflecting bi-directional losses by fiber and installed span loss by fiber.
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Q) What are carrier neutral collocation facilities?
In many cities, companies are building facilities to allow the interconnection of networks between competing service providers and for the hosting of web servers, storage devices, etc. They are rapidly becoming the obvious location for terminating customer owned dark fiber.
These facilities feature diesel power backup systems and the most stringent security systems. The facilities are open to carriers, web hosting firms and application service firms, internet service providers, etc.
Most carrier neutral open collocation facilities feature a "meet-me" room where fiber cables can be cross-connected to any service provider within the building. With a simple change in the optical patch panel in the collocation facility the customer can quickly and easily change service providers on very short notice.
Many of these concepts of carrier neutral collocation facilities were first developed with the next generation Internet programs in the United States and Canada with a concept called a GigaPOP. Leading researchers and universities recognized that there were many benefits to interconnecting to carriers at a common "meet me" point. So rather than having multiple carriers build separate facilities to university campuses, the universities instead built one single telecommunication facility to a GigaPOP and then interconnected to one or more carriers on a new demarcation point that was not on the customer premises.
Sunesys has entry into various collocation facilities in each market served.
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