D

Dark Fiber
Dark fiber or unlit fiber is the name given to fiber optic cables which have yet to be used. They are hence not yet connected to any device.

Data Center
A data center is a facility used for housing a large amount of electronic equipment, typically computers and communications equipment.

Dedicated Internet Access
NextLevel Internet offers high-capacity connections for our clients backed by a world class Service Level Agreement. The NextLevel Internet service is designed to provide the premium quality connectivity necessary to support corporate applications.

Denial of Service (DoS) attack
An attack on a computer system or network that causes a loss of service to users, typically loss of network connectivity and services by consuming the bandwidth of the victim network or overloading the computational resources of the victim system.

Disk Space
Disk space is the amount of space that your computer has on it, and is measured in MB (megabytes) or GB (gigabytes).

Diverse Routes
Merged routes from multiple carriers.

Domain Name Service (DNS)
The Internet service that translates server names (NextLevelInternet.com) to IP addresses (63.215.241.202).

DS1
A standard digital circuit. A DS1 circuit can carry 24 channels - each channel is 64 kb/sec, for a total 1.53 Mb/s. Each channel can handle a voice call or data. Groups of channels can be combined to create a single faster digital connection. Also referred to as a T1 or Clear Channel 1.5 Mb/s

DS3
A very high capacity digital circuit. A DS3 is roughly 28 times faster than a T1 - it carries 673 channels and contains 44 Mb/sec of capacity. Also referred to as a T3.

Domain
A domain name is the unique name of a computer on the Internet that distinguishes it from the other systems on the network.

Every website, email account, etc, on the Internet is hosted on at least one server. Each server has a unique IP address which is nothing but a set of numbers, such as “63.215.241.202.” To access a particular Internet service, one can specify its IP address in an appropriate application, such as an FTP client; however because it is difficult to remember numbers, an IP address can be associated with a fully qualified host name (a domain name), such as NextLevelInternet.com

 

F

Facility
A general term for the transmission media and equipment in communications networks; i.e., the "pipes" that carry information signals. Facilities include the physical copper pairs in a cable, carrier systems, coaxial cables, fiber optic cables, and radio and satellite systems.

Firewall
A security system designed to restrict access to computers on a Local Area Network (LAN) from the outside world, which usually means the Internet.

Fractional T1
A T1 installation in which the full circuit is installed, but only some of the 24 channels are used.

Frame Relay
Frame Relay is a high speed technology, typically used to build a Wide Area Network (WAN) for large organizations. Frame relay networks can be either over public or private networks. Frame relay can support TCP/IP connections, but is primarily aimed at SNA (IBM) mainframe network environments or multiplexing Voice and data over from a branch office over a single circuit using statistical multiplexing rather than TDM (Time Division multiplexing). If devices only send bursty data from time to time, TDM is a very inefficient use of a circuit / channel.

 

G

Gateway
This is a device that passes data between two different systems on a network. This includes supporting voice communication between terminals on a packet, e.g., Internet Protocol (IP) network and terminals on a circuit (e.g., Public Switched Telephone Network (PSTN).

Gigabit Ethernet (GIG-E)
The newest version of Ethernet, which supports data transfer rates of one gigabit (1,000 megabits) per second.

 

H

HVAC
Heating, Ventilation, and Air Conditioning

Host
Any device that is accessible on a network.

 

I

Internet Control Message Protocol (ICMP)
The Internet Control Message Protocol (ICMP) is part of the Internet protocol suite. ICMP messages are typically generated in response to errors in IP datagrams or for diagnostic or routing purposes.

Internet Service Provider (ISP)
A company that provides Internet access to the public or to other organizations. Most offer a full set of Internet services and provide access at either hourly rates or for a flat monthly fee.

Internet Protocol (IP)
Internet Protocol is one layer of a set of protocols which devices on the Internet use to communicate with each other. It defines how packets of data get from their source to their destination.

Internet Protocal address (IP address)
An IP address is a unique number, akin to a telephone number or street address, used by computers to refer to each other when sending information over the Internet.

IP Telephony
Any of a number of techniques allowing voice communications using Internet technologies and protocols.

Installation Fee
The time interval between the instant a device makes a request for data and the instant at which the response is started.

 

L

Latency
The time interval between the instant a device makes a request for data and the instant at which the response is started.

Legacy System
A system (and the associated programs, processes, and procedures already in place) currently deployed and in use within an organization. Considered in reference to new components, or when migrating to a new system. For example, when upgrading software within an organization, the legacy applications and procedures must be considered.

Link
A Physical Layer communication path between adjacent network nodes.

Local Exchange Carrier (LEC)
A company in your town who offers you “dial tone” service. The main types of LECs are ILECs (Independent Local Exchange Carriers) and CLECs (Competitive Local Exchange Carriers).

Letter of Agency (LOA)
A letter allowing a person or business to act on behalf of another.

Local Loop
The connection between the central office and the customer's premises. Also referred to as the “last mile.”