O
OC-192
Optical carrier level 192. SONET channel capable of carrying 10 gigabits per second.
OC-48
Optical carrier level 48. SONET channel capable of carrying 2.488 Gigabits per second.
OC3c SONET
A SONET-based fiber-optic User-to-Network Interface (UNI), either public or private, operating at 155.52 Mbps over single-mode and multimode optical fiber.
OR Logic Gate
in semiconductor technology, a type of logic gate whose output considers either the first or the second input before producing its output. for more info.
OSI
Open Systems Interconnection. A reference model usedto describe layers of a network and the types of functions expected at each layer. The OSI model is used as a standard, letting developers of networks and communication systems rely on the presence of certain functions at certain places in a standard system.
OSPF
Open Shortest Path First
Octet
Eight data bits.
Off Hook
A state that results when you lift a telephone receiver, producing a busy signal.
Offset
The offset of a port is the difference between its address and the address of the first port in a contiguous group of ports. The offset of a memory location is the difference between its address and the address of the first memory location in a contiguous memory window.
Open System
Any system based on publicly available standards for subsystem interaction that facilitates multivendor and multitechnology integration.
Open Systems Interconnection
A 7-layer framework of standards for network communication that enables different systems to exchange information regardless of vendor or platform.
Open Systems Interconnection Reference Model
The OSI Reference Model describes the layers of a network, details the functions of each layer, and explains how to connect communications devices on a LAN or WAN. Each layer provides services for the layer above it, and uses the services of the layer below it.
Operating System (OS)
A software program that manages the basic operations of a computer system. The OS controls how main memory is apportioned, how and in what order tasks are handled, how information flows into and out of the main processor, how material is sent to printers for printing and to the screen for viewing, and how information is received from the keyboard.
Operations System (OS)
Software and the necessary hardware that controls, monitors, manages, maintains, and performs the functions needed to keep the network operating efficiently. Not to confused with Operating System, like DOS, Windows, and the Macintosh System. An OS is the control program that runs the computer.
Operations, Administration, Maintenance, and Provisioning
In telecommunications, denotes the functions provided by an operations system to assure continuing service as well as to launch new service offerings.
Operations, Administration, and Maintenance
In telecommunications, OA&M denotes functions such as technician interfaces, diagnostics, service measurements, and status reports.
Optical Carrier (OC)
A hierarchy of optical signals used to classify speeds, or capacities, of fiber lines, especially as related to the SONET standard. The basic speed is OC-1 (52 Mb/second). An OC-48 fiber line has a capacity of 2.5 gigabits a second and an OC-192 line 10 gigabits a second.
Optical Fiber
Long strands of glass, thinner than a human hair, which propagate a lightwave signal for use in broadband communications. Synonym for fiber, lightguide.
Optical Network
A network that carries digitized voice or data at very high rates on multiple channels of light.
Optical input
The optical input to a photodiode or optical receiver.
Optical isolator
A device used to suppress or redirect backscattered or backreflected light.
Optical loss
The amount of a signal's power lost, expressed in dB. This is due to a fibers length, amount of splices, bend radius or any mechanical external factors placed on the fiber.
Optical output
The optical output power of a laser or optical transmitter.
Optical reflections
The optical power (expressed in dB) reflected by a component or an assembly.
Optical return loss
The ratio (expressed in dB) of optical power reflected by a component or an assembly to the optical power incident on a component port when that component or assembly is introduced into a link or system.
Optoelectronics
Materials and devices associated with fiber optic and infrared transmission systems. Opto-electronic light sources convert electrical signals to an optical signal that is transmitted to a light receiver and converted back to an electrical signal.
Out-of-band connection
A remote link, or a link outside connected networks, established over a modem. It is useful when network communications are not available.
Out-of-band signaling
in telecommunications, the transmission of signaling information over a different path from data and/or voice information. CCS7 uses out-of-band signaling.
Out-of-frame Condition
A condition in which the T1 line, DS3 line, or DS2 stream cannot receive or transmit data because the Lucent unit has lost the frame alignment on the received signal.
Output power
See optical output
Overflow
The process of dialing additional bandwidth to accommodate peak traffic loads, and reducing the total bandwidth during times of reduced traffic loads.
Optical carrier level 192. SONET channel capable of carrying 10 gigabits per second.
OC-48
Optical carrier level 48. SONET channel capable of carrying 2.488 Gigabits per second.
OC3c SONET
A SONET-based fiber-optic User-to-Network Interface (UNI), either public or private, operating at 155.52 Mbps over single-mode and multimode optical fiber.
OR Logic Gate
in semiconductor technology, a type of logic gate whose output considers either the first or the second input before producing its output. for more info.
OSI
Open Systems Interconnection. A reference model usedto describe layers of a network and the types of functions expected at each layer. The OSI model is used as a standard, letting developers of networks and communication systems rely on the presence of certain functions at certain places in a standard system.
OSPF
Open Shortest Path First
Octet
Eight data bits.
Off Hook
A state that results when you lift a telephone receiver, producing a busy signal.
Offset
The offset of a port is the difference between its address and the address of the first port in a contiguous group of ports. The offset of a memory location is the difference between its address and the address of the first memory location in a contiguous memory window.
Open System
Any system based on publicly available standards for subsystem interaction that facilitates multivendor and multitechnology integration.
Open Systems Interconnection
A 7-layer framework of standards for network communication that enables different systems to exchange information regardless of vendor or platform.
Open Systems Interconnection Reference Model
The OSI Reference Model describes the layers of a network, details the functions of each layer, and explains how to connect communications devices on a LAN or WAN. Each layer provides services for the layer above it, and uses the services of the layer below it.
Operating System (OS)
A software program that manages the basic operations of a computer system. The OS controls how main memory is apportioned, how and in what order tasks are handled, how information flows into and out of the main processor, how material is sent to printers for printing and to the screen for viewing, and how information is received from the keyboard.
Operations System (OS)
Software and the necessary hardware that controls, monitors, manages, maintains, and performs the functions needed to keep the network operating efficiently. Not to confused with Operating System, like DOS, Windows, and the Macintosh System. An OS is the control program that runs the computer.
Operations, Administration, Maintenance, and Provisioning
In telecommunications, denotes the functions provided by an operations system to assure continuing service as well as to launch new service offerings.
Operations, Administration, and Maintenance
In telecommunications, OA&M denotes functions such as technician interfaces, diagnostics, service measurements, and status reports.
Optical Carrier (OC)
A hierarchy of optical signals used to classify speeds, or capacities, of fiber lines, especially as related to the SONET standard. The basic speed is OC-1 (52 Mb/second). An OC-48 fiber line has a capacity of 2.5 gigabits a second and an OC-192 line 10 gigabits a second.
Optical Fiber
Long strands of glass, thinner than a human hair, which propagate a lightwave signal for use in broadband communications. Synonym for fiber, lightguide.
Optical Network
A network that carries digitized voice or data at very high rates on multiple channels of light.
Optical input
The optical input to a photodiode or optical receiver.
Optical isolator
A device used to suppress or redirect backscattered or backreflected light.
Optical loss
The amount of a signal's power lost, expressed in dB. This is due to a fibers length, amount of splices, bend radius or any mechanical external factors placed on the fiber.
Optical output
The optical output power of a laser or optical transmitter.
Optical reflections
The optical power (expressed in dB) reflected by a component or an assembly.
Optical return loss
The ratio (expressed in dB) of optical power reflected by a component or an assembly to the optical power incident on a component port when that component or assembly is introduced into a link or system.
Optoelectronics
Materials and devices associated with fiber optic and infrared transmission systems. Opto-electronic light sources convert electrical signals to an optical signal that is transmitted to a light receiver and converted back to an electrical signal.
Out-of-band connection
A remote link, or a link outside connected networks, established over a modem. It is useful when network communications are not available.
Out-of-band signaling
in telecommunications, the transmission of signaling information over a different path from data and/or voice information. CCS7 uses out-of-band signaling.
Out-of-frame Condition
A condition in which the T1 line, DS3 line, or DS2 stream cannot receive or transmit data because the Lucent unit has lost the frame alignment on the received signal.
Output power
See optical output
Overflow
The process of dialing additional bandwidth to accommodate peak traffic loads, and reducing the total bandwidth during times of reduced traffic loads.
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