NDTC Fiber Optic Information
OVERVIEW
Features and Benefits Fiber optic cable has many benefits over copper. First and foremost, fiber optic cables have a huge capacity, at minimum many times as much as traditional copper. Also, fiber is not conductive, so there is no possibility of electrical interference from outside sources. NDTC is mostly using buried fiber, which has an advantage over overhead cable in that it is less likely to be damaged by storms, falling trees, animals, etc. Traditional telephone is based on electrical signals. The electrical signals are converted into a data stream that is sent from the CO to the customer premise through the fiber optic cable as light. The rules that govern and control the transmission is called ethernet. This is the same type of communications that your computer uses when communicating on the Internet. Ethernet was developed in the early 1970s, so is very mature and widespread. Ethernet is also very versatile. Two technologies, VLANs and QOS, keep the different services from interfering with each other and make sure that the most important information gets to the premises first. More on this later. First, more on the physical makeup of the new plant. Active vs. Passive Fiber Technology There are two types of fiber technology, Active and Passive. Passive Optical Networks, or PONs, can be compared to the old party line telephones or cable networks. PONs utilize splitting technology that allows one fiber to feed up to 64 endpoints (1 by 64). This technology allows the serving company to minimize the number of fibers they have to plow into the ground, and gives them the ability to oversubscribe the fiber backbone to the premise. However, since each group of subscribers share the same link back to the central location, they are each limited to what is left after everyone else has their share. An active network, on the other hand, is just the opposite. No splitters are used in this type of network. Each subscriber has their own link back to the central location. This gives each subscriber the full bandwidth of the fiber, and subscribers can not be interfered with by a neighbor. It allows unlimited potential for each customer. NDTC's system design proved very minimal cost differences between active and passive networks, allowing NDTC to be the first North Dakota company to deploy a production active fiber to the premises (FTTP) network, including all major North Dakota metropolitan areas. What does this mean for our customers? Each subscriber to NDTC's services will enjoy more dedicated bandwidth, allowing the following:
The actual fiber network resembles a tree. The "roots" of the tree are in the Central Office (CO), where NDTC's phone switch and main Internet connections are. The "trunk" of the tree (the bundles of fiber leaving the CO) run underground to the node sites (sometimes called "huts"). These fibers connect the electronic equipment in the CO to the electronic equipment running to each customer premise. The electronics in the hut have redundant physical and electronic links back to the CO, as well as redundant physical and electronic links to each other. So, if there are four devices in the hut, they will each be linked to each other in a ring configuration, allowing any one of the links to go down without affecting any service. Likewise, the groups of devices will be connected back to the CO in a ring configuration as well, negating the effects of any fiber cut leading to the hut. Each group of devices in the hut is fed with a multi-gigabit connection, sized to allow each subscriber to use 100% of their available bandwidth without sacrificing or interfering with any other subscriber. The fiber running to each customer can be considered branches on the tree. Each subscriber has up to 100 megabits per second connection, to be used for all services, in a standard configuration. So, if the internet connection is using 10 megabits per second, there is still 90 megabits per second available for other services. One (1) gigabit speeds to a customer premise are also available, for those extremely high use customers who need it. Remember, current DSL speeds are around 4 megabits per second for Internet. Phone service originates in a Nortel DMS-100 class 5 phone switch, located in the CO. The electrical signals are converted to ethernet communications, using a piece of equipment called a media gateway. The newly created ethernet stream is transported via the fiber optic cable on a specific VLAN to the customer's premise, where the Optical Network Terminal (ONT) decodes the ethernet stream tagged with the specified VLAN and converts the conversation to the original electrical signal at the telephone port. The leaves on the tree are the customer premises. Each residential ONT has up to 4 distinct phone lines, as well as 6 network (ethernet) ports available for different services, such as Internet and video. More of each type of port are available with business type ONTs, as well as T-1 ports for connections to phone systems. Voice is given a high Quality of Service (QOS) rating, to ensure quality and reliability. The ONT will work with any normal analog phone. What is a vlan? We've mentioned VLANs. www.wikipedia.com defines a VLAN as "A virtual LAN, commonly known as a vLAN or as a VLAN, is a logically-independent network. Several VLANs can co-exist on a single physical switch." VLANs are the most important difference between active and passive optical networks. VLANs allow isolation of services the focal point of the infrastructure and design of the network, allowing many services to co-exist on the same fiber without interference. VLANs are used to separate and distribute each individual service (voice, video, internet) to the customer. Since VLANs are logically independent networks, the video VLAN cannot interfere with the internet or voice VLAN, meaning that a virus on a customer's PC is not going to affect their phone service or cause distortion of the video service. There are three components required at the customer premises. First, the fiber itself. Second, there is an ONT, the device that converts the optical signal off of the fiber to the electrical signals required by the telephone. Third, a UPS provides power to the ONT, and keeps the ONT (and phone service) running during a power outage. The UPS contains batteries, which are monitored by our Repair center. Again, NDTC retains ownership of equipment needed at customer premises, to allieviate customer responsibility for required maintenance. The placement of the customer premises equipment (ONT and UPS) will be determined with customer input and convenience whenever possible.
No discussion about fiber optics is complete without a section on fiber optic safety. Fiber can carry many types of light, from decorative lighting to high intensity LASER light. The fiber in the NDTC FTTP installation carries high frequency LASER light, which is in the infared spectrum and is invisible to the naked eye. This type of light can cause blindness if directed into the eye for even a short period of time, and can actually cause a burn on the skin if pointed at tender skin for a longer period of time. Never look into the end of a fiber optic cable!! There are no user servicable parts in the equipment installed in the home. Please, never disconnect the fiber optic line from the ONT. Besides the obvious risk to your eye health, the fiber can become dirty or damaged if handled improperly, causing outages and loss of signal. If there is a problem, please contact NDTC to have a qualified technician inspect and repair the problem. CPE - Customer Premise Equipment, encompasses any equipment or materials needed and located at the customer's premises to provide the service to the customer. HD - High Definition video, a video standard that is much more detailed than ordinary video. FTTP - Fiber To The Premise, denotes services provided by a service provider being transmitted over a fiber optic medium from the service providers location all the way to the customer's premise. ONT - Optical Network Terminal, the end device on an optical network (such as FTTP) which converts the optical signal carried by the fiber optic network to a variety of other signals, such as electrical, to provide the services in their native form. QOS - Quality Of Service, a phrase encompassing the concept of data traffic queuing and passing, allowing a service provider to give a higher precedence to certain types of traffic where needed. For example, voice traffic must be passed efficiently to prevent clipping and ensure a clear, smooth voice quality. Internet data can be queued and passed after voice, as a few milliseconds of delay in the data traffic will present no noticable difference in quality, whereas a few milliseconds delay in a voice transmission can cause noticable quality problems. T-1 - T-carrier 1 or DS1, Digital Signal 1, is a widely used telecommunications standard. Typically, a T-1 carries 24 standard voice circuits (called a DS0), each of which is able to carry 64 kilobits of data. DS0s can be combined in many ways, up to a total of 1.544 megabits per second, or Mbps. Business phone systems can use T-1s as an efficient way to access many phone lines. UPS - Uninterruptible Power Supply, allows devices connected to continue working in a power outage. A UPS contains a battery for energy storage, a charging system to keep the battery charged while connected to a power source, and a power converter to convert the (typical) 12 volt battery power to the output required by the connected equipment. VLAN - Virtual Local Area Network, logically independent data networks on shared physical medium. VOD - Video On Demand, allows a customer to view video content interactively, as opposed to Pay Per View, where the customer must wait on a schedule determined by the video carrier. |
Traditionally, phone service is provided using a pair of copper wires running
from a central office (CO) to a customer's premise. This type of plant has
worked very well for many, many years, but it has its limitations. NDTC is
upgrading the traditional copper based plant to a fiber optic plant. There
are a few reasons for this change:
