Tuesday, June 14, 2011

Choosing Dark Fiber vs Lit Fiber Service

When your applications are demanding enough to require fiber optic transmission, you’re faced with a choice. Do you order one of the lit fiber services available for your business location or do you buy or rent dark fiber and create your own transport services?

Choosing between dark and lit fiber optic options. Click for pricing and availability.The tradeoffs can be tricky, so you’ll probably want to set up a spreadsheet to compare the performance, cost and installation time for all the services you are interested in.

Installation time? By focusing strictly on cost, you can get caught in a situation where you’ll have the best deal possible... whenever they can get it installed. That can be weeks or even months if you have a particularly difficult situation. Will that meet your needs? If you do your planning well in advance, it just might. If circumstances conspire to demand an order of magnitude bandwidth increase immediately, availability may trump lease cost.

The dark vs lit fiber tradeoff is the classic own vs rent situation. Most companies choose to survey the marketplace for bandwidth services and pick the least cost solution that meets their needs. That process is made easy by using a telecom broker, like Telarus, Inc., that represents dozens of service providers. If you have enough competition for your business, you can get much better pricing than if you are eye to eye with the only telecom sales person for a hundred miles.

One characteristic of both dark and lit fiber services is that they are extremely location sensitive. There may well be accessible fiber running on your side of the turnpike and nothing on the other side, or vice versa. Some buildings have already been “lit” by a particular carrier while others remain dark. Those dark buildings may or may not justify the construction costs of bringing in new fiber connections depending on location and how much service is needed by the tenants.

Lit fiber falls into several major categories. The traditional telecom service is SONET/SDH with OC-3 as the lowest bandwidth of 156 Mbps. An OC-3 can also carry 3 multiplexed DS3 circuits at 45 Mbps each. It’s common for companies to order DS3 and have it delivered by fiber optic cables of much higher capacity. Other SONET levels are OC-12 at 622 Mbps, OC-24 at 1.2 Gbps, OC-48 at 2.5 Gbps and OC-192 at 10 Gbps.

The hot competition for fiber optic bandwidth is Carrier Ethernet. Ethernet tends to be both more scalable and lower cost than SONET where it is available. That availability is becoming more and more common, thanks to aggressive build-outs by competitive carriers and business demand for higher bandwidths at lower costs.

Typical fiber optic Ethernet service levels are 100 Mbps Fast Ethernet, 250 Mbps, 500 Mbps, 1 Gbps Gigabit Ethernet and 10 Gbps 10GigE. Lower bandwidth such as 50 Mbps Ethernet that competes directly with DS3 may be provisioned on either copper or fiber, depending on the carrier’s available equipment.

Coming on strong for higher bandwidth fiber optic connections is wavelength services. When you order a wavelength, you are getting a virtual fiber all to yourself. Of course, there are many wavelengths on the same physical glass fiber strand, but they differ in color and do not interact. Wavelength services may sense for 10 Gbps requirements, with the added advantages of low latency and high security. With an entire wavelength dedicated to your use, you can use a different protocol than other customers on the fiber. You may be running Ethernet while others are running SONET.

The ultimate in flexibility is dark fiber. By leasing a dark fiber run, you have all the wavelengths at your disposal. You’ll have to buy the termination equipment for each end, but then you’ll have the option to light up as few or many wavelengths as you want. You can run a different protocol on each wavelength and even operate with something non-standard or experimental. Usually it is the largest companies with the most complex IT requirements that go the dark fiber route.

What type of fiber optic service makes the most sense for your operation? Don’t jump to any conclusions until you get a complete set of prices and install times for fiber optic options available for your business location or locations.

Click to check pricing and features or get support from a Telarus product specialist.

Note: Light bulb photo courtesy of Ulfbastel on Wikimedia Commons.

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