Glossary

100

100G OIF Coherent
A 100G long haul DWDM transceiver module, non-pluggable, modulated as 100G PM-QPSK, with coherent detection on the receive side. This is a full C-band, multi source agreement (MSA) module with single tunable 50GHz, and can reach approximately 2000 km without the need for dispersion compensation. The module supports OTU4, usually with internal soft decision forward error correction (SD FEC) capability implemented using a powerful digital signal processing (DSP). The framework for this optical module was defined by the Optical Internetworking Forum (OIF).

A

Attenuation
Attenuation in optical networks refers to a loss of intensity of the light signal over distance in a fiber optic cable. Measured in dB/km, attenuation is a significant factor when planning an optical network and is taken into consideration by any optical engineer. In order to compensate for attenuation, often optical amplifiers are used, also called Erbium-doped fiber amplifier (EDFA).
AGC
Automatic gain control (AGC) in optical networking refers to a method of automatically adjusting the gain of the receiver to maintain a constant average output level for wavelength stream in an optic fiber. AGC is usually used in EDFAs as one of two automatic adjustment methods.
APC
Automatic power control (APC) in optical networking refers to a method of automatically adjusting the power (or attenuation) of the receiver to maintain constant average output level for wavelength stream in a fiber optic cable. APC is usually used in EDFAs as one of two automatic adjustment methods. 

B

BBU
Baseband unit (BBU) refers to a unit in the mobile operator network which creates radio signal.

C

C-band
C-band in optical networking refers to a section of wavelengths (colors) that ranges between 1530nm to 1565nm.
C-RAN
Centralized or cloud radio access networks (RAN) - is a network architecture that allows mobile operators to have distributed networks between baseband units (BBU) remote radio heads (RRH), where local cells are decentralized with most of the network management infrastructure located at the central office instead of the BBU. Also referred to as Fronthaul networks.
CFP
Century form factor pluggable (CFP) is an optical transceiver module typically used for 100GbE and 100G OTU4 OTN data rates. The CFP can be used as a client interface or uplink coherent interface. The optical interface can support a number of lanes, which can operate over multimode (MM) or single mode (SM) fiber, and the electric interface on the host side is composed of 10 lanes of 10G. The CFP can reach 10km/40km in SM and 100m in MM. Available formats of the optical interfaces are LR4, ER4 and SR10 on the client side, and coherent tunable transceiver on the DWDM line side, reaching over 1000km without the need for DCM or regeneration sites.
CFP2
Century form factor pluggable 2 (CFP2), an optical transceiver module, usually for 100GbE data rate. It has a smaller form factor than the CFP and consumes less power, enabling higher port density. The electrical interface depends on the application, can be 10 lanes of 10Gb/s or 4 x 25Gb/s or 4x 28Gb/s . The optical interface will usually be 4 lanes of 25Gb/s over single mode fiber. The CFP2 pluggable module supports both 100Gb Ethernet and OTN OTU4.
CFP2-ARO
Century form factor pluggable 2 analog coherent optics (CFP2-ACO) is a pluggable coherent optics transceiver for next generation 100G and 200G metro systems. The transceiver is tunable, pluggable and provides cost and power consumption reduction for 100G/200G single wavelength coherent DWDM applications. The transceiver also facilitates pay-as-you-grow benefits, as bandwidth is easily increased by just adding transceivers. The CFP2-ACO is popular with system designers thanks to its multi-source agreement (MSA) form factor, increased bandwidth density, and the fact that it is interoperable between multiple optical transceiver vendors. The CFP2-ACO is dual rate and enables transmission distance as high as 2500km in 100G DQPSK modulation or 600km in QAM 200G modulation, coupled with the DSP on the host board.
CPE
Customer premises equipment (CPE) is carrier or service provider equipment that is located on the customer's premises (physical location) rather than on the carrier or service provider premises, network, or in between. The equipment can be owned by the customer or by the carrier/provider.
CPRI
Common Public Radio Interface (CPRI™) - is a digital radio frequency protocol used in transporting radio signals over fiber in mobile networks. It is commonly used in fronthaul networks. The following CPRI rates are standardized: 614.4Mbit/s, 1228.8 Mbit/s, 2457.6 Mbit/s, 3072.0 Mbit/s, 4915.2 Mbit/s, 6144.0 Mbit/s, 9830.4 Mbit/s.
Crosstalk
Crosstalk is a phenomenon which occurs in optical networks where information from one channel crosses over into another channel, causing distortion in the transmitted signal. PacketLight's solutions eliminate crosstalk in WDM networks by using independently colored channels (wavelengths).
CWDM
Coarse wavelength division multiplexing (CWDM) is one of two types of WDM multiplexing technologies. CWDM is the lower cost solution, offering up to 16 channels (wavelengths) per each fiber pair, making it the initial entry point for many organizations. CWDM operates in the spectral range of 1310nm to 1550nm. Each CWDM wavelength typically supports up to 2.5Gbps and can expand to 4.25Gbps. This transfer rate is sufficient to support protocols such as Fast Ethernet, Fibre Channel, and STM-1/STM-4/STM-16. CWDM is primarily used in applications of up to 80km, as the signal waves are spaced further apart and cannot support amplification.
CXP
Century small form-factor pluggable (CXP) is an optical transceiver that provides 12 x 10Gb/s lanes suitable for 100GbE in short distances of up to 100m. The electrical side is 12 lanes of 10Gb/s. The optical side is 12 lanes of 10Gb/s over 12 multimode fibers. In case of 100G, only 10 lanes are used. The small dimension of the CXP and its low power consumption, make it the lowest cost 100G interface available in the market.

D

Dark Fiber
In optical networking, dark fiber is unused (or unlit) fiber, that is ready for use.
DCM
In optical networking, dispersion compensation modules (DCM) are used to compensate dispersion in long spans of transmission fiber. The DCM provides two types dispersion - fixed and tunable. The DCM is usually placed between two fiber amplifiers, or at the beginning or end of the link. Installation is simple, using the module's input and output fiber connectors. The DCM is typically used for 10G backbone and ROADM infrastructure zeroing the dispersion of each segment.
Demarcation Point
The demarcation point is the physical point in which a carrier's or service provider's network ends and the customer's network begins, and defines where the carrier's / service provider's responsibility for the network ends. It can also indicate the demarcation, or defining point between transport Layer-2/3 and the DWDM/OTN Layer-1 infrastructure. The demarcation point includes performance monitoring, loopback and other diagnostic means to isolate issues and detect the faults in the network. In the demarcation point either 3R (retiming, reamplifying/shaping, and regeneration) or mapping of the client interface signals onto OTN ensure an error free optical layer.
Demultiplexer (Demux)
A demultiplexer (demux) is an electronic device that receives one input signal containing multiple signals and splits it into multiple electronic signals while maintaining the integrity of each signal.
In optical networks, the demultiplexer separates one optical signal containing multiple signals each coded in its respective, color into separate data rates.
Dispersion
Dispersion in optical networking is where wavelength velocity (or speed) is dependent on its frequency. Changes in frequency cause a delay in the light pulse, degrading the optical signal over long distances.
Some data rates, such as 10G, are more sensitive to dispersion than others. To prevent dispersion and ensure the integrity of the optical signal, dispersion compensation modules (DCM) are placed strategically along the optical link.
DWDM
Dense wave division multiplexing (DWDM) is one of two types of WDM multiplexing technologies. DWDM is a technology with much higher throughput capacity than CWDM transferring data of 10G FC, 10GbE, and STM-64.
Some DWDM systems provide up to 144 wavelengths of mixed service types, and can transport to long distances by integrating amplifiers and dispersion compensators. DWDM technology is more costly, but is a better solution for large capacity data transport and connectivity over long distances.

E

EDFA
Erbium-doped fiber amplifier (EDFA) is an optical device that amplifies optical signals without converting them to electrical signals, making it possible for them to reach further distances (between 80km and 200km) without intermediary nodes. EDFAs are commonly used in DWDM networks. PacketLight offers three types of EDFAs: pre-amplifiers, boosters, and inline amplifiers.
Encryption
Fiber optic cables can be tapped and the data transmitted can be extracted, with the main concerns being confidentiality, data integrity, and authentication. This has lead to an increase in data security over DWDM and OTN links, including security requirements and regulations put into place. One of the solutions to deal with this threat is encryption of the information transmitted. Implementing encryption at the optical layer (Layer-1) of the client signal has several advantages over Layer-2/3, as Layer-1 supports multiple client protocols, does not allow for omissions and is easier to deploy. Most importantly, encryption on Layer-1 is transparent to the traffic at full bandwidth without any degradation to the DWDM link, whereas Layer-2/3 reduces the bandwidth of the data transport up to 50% due to high overhead. The optical layer can also detect tapping attempts as it constantly monitors the power levels of the DWDM channels and alerts of any change.
ER4 (100GBase-ER4)
100GBase-ER4 refers to 100Gb Ethernet. It is a port type of an extended range (ER) optic for single mode fiber. It uses four wavelengths in the 1300nm each carrying 25Gb/s for a distance of 40km. The mux/demux of the four wavelengths is built inside the modules, and its interface is dual LC fiber. The ER4 optical modules can also support OTN OTU4 100G rate.
ESCON
ESCON (Enterprise Systems Connections) is a method of data connection proprietary to IBM. The method utilizes a half-duplex optical fiber with serial interface. It is used mainly for connecting peripheral devices (printers, tape drives, disk storages) to IBM's mainframe computers. PacketLight's solutions support ESCON based connectivity.

F

FEC
Forward error correction (FEC) refers to an error-controlling mechanism in data transmission. FEC allows the sender to add redundant data to the transmitted information, aiding the receiver to identify and correct any errors in the data. FEC boosts the network optical performance by a factor of at least 4 (6dB coding gain), and is a major feature of the OTN network. It is standardized by both ITU-T G.709 and ITU-T G.975 specifications.
Fibre Channel (FC)
Fibre Channel (FC) is a standardized gigabit transport technology utilized in storage devices and storage networking. The transport rates are 1/2/4/8/10/16/32G FC. PacketLight supports all FC rates over long distances.
FICON
FICON (fiber connection) is a proprietary IBM Fibre Channel protocol used primarily in mainframe computers. PacketLight products provide full support for FICON FC protocol.
FIPS
Federal Information Processing Standards (FIPS) were developed by the US federal government for use in computer systems by non-military government agencies and government contractors. The standards establish requirements for purposes such as ensuring computer security and interoperability, for example encyption and data security. PacketLight encryption device PL-1000TE-Crypto complies with FIPS 140 security requirements for cryptography modules (specifically, FIPS standard 140-2).
Fronthaul Network
Fronthaul network, also referred to as centralized or cloud radio access networks is a network architecture that allows mobile operators to have distributed networks between baseband units (BBU) and remote radio heads (RRH) where local cells are decentralized with most of the network management infrastructure located at the central office instead of the BBU.

G

GDPR
The General Data Protection Regulation (Regulation (EU) 2016/679), is intended at strengthening and unifying data protection for all individuals within the EU, including export of personal information outside the EU. The idea behind this regulation is to give control back to individuals and simplify regulations for international businesses. The main idea behind this regulation is the need for consent from individuals to collect personal details, and the ability to withdraw this consent at any given time, with the information being permanently deleted. Where previous regulation focused on large businesses, the new regulation specifically includes small to medium enterprises (SME), following the understanding that cyber criminals perceive SMEs as easier targets.
The GDPR will take effect in May 2018, replacing the 1995 data protection directive (Directive 95/46/EC).

I

Insertion Loss
Insertion loss, expressed in dB is defined as 10*log (Pout/Pin of a signal of an optical component) where Pout = Signal Power at Output, and Pin = Signal Power at Input.
In optical networks the insertion loss of a component is one of the main factors influencing the error-less reach of optical transmission. Optical amplifiers are typically used to compensate for insertion losses along the optical path.
ITU
International Telecommunication Union (ITU) is a part of the UN family responsible for managing communication and technology issues for world governments and corporate communities. ITU is best known for its activities in establishing certain standards for technology and telecommunication equipment, as well as monitoring the international radio-frequency spectrum, and spreading the technology around the world. ITU standards are recognized worldwide, and organizations strive to meet these standards. PacketLight WDM equipment meets ITU standards, making PacketLight part of the ITU approved telecom equipment list.

L

L-band
L-band in optical networking refers to a section of wavelengths (colors) of light that ranges between 1565nm to 1625nm.
LAN
A local area network (LAN) is a group of devices that share a common communications line. The LAN network is usually concentrated in a relatively small area such as a single room, building or group of buildings.
Latncy
Latency in optical networking refers to the time it takes for a signal to reach from start point to end point.  This time is usually measured in milliseconds and is especially important in applications that require a speedy transfer (i.e. low latency) of information such as voice, video, and financial transactions.
Layer-1, Layer-2, Layer-3
In fiber optic networks, networking standards are separated into layers:
Layer-1 - the physical layer - electrical and optical hardware where the electrical signals are converted into light, so they can be transported over fibers for short distances inside the data center or over long haul DWDM optical networks.
Layer-2 - the data link layer - handles errors in the physical layer, provides flow control, and frame synchronization.
Layer-3 - the network layer - switching and routing data from node to node.
LR4 (100GBASE-LR4)
100GBASE-LR4 refers to 100Gb Ethernet. It is a port type of a long range (LR) optic for single mode fiber. It uses 4 wavelengths in the 1300nm each carrying 25Gb/s for a distance of 10km. The mux/demux of the 4 wavelengths is built inside the modules, and its interface is dual LC fiber. The LR4 optical modules can also support the OTN OTU4 100G rate.
LR10 (100GBASE-LR10)
100GBASE-LR10 refers to 100G Ethernet. It is a port type of a long range (LR) optic for single mode fiber. It uses 10 multiplexed wavelengths in the 1550nm each carrying 10Gb/s for a distance of up to 40km. The module has 10 channels with internal mux/demux with dual LC fiber. The LR10 optical modules can also support the OTN OTU4 100G rate.

M

Metro Ethernet
Metro Ethernet is an Ethernet-based standard and is often used to connect branch offices and other homogeneous organization to internal Internet (Intranet). Metro Ethernet computer network covers a large metropolitan area in order to connect users and businesses to the Internet.
Multimode (MM) Fiber
Multimode fiber has a larger diameter core for light path than single mode fiber. In multimode fiber, light propagates in multiple modes, each taking a slightly different path through the fiber and travelling at a slightly different velocity for a given fiber length. The multimode optical light source is based on low cost LEDs and electronics, making multimode fiber networks a much more cost-effective optical connectivity solution. However, the low light concentration makes this solution applicable for short distances of between 300m and 550m. PacketLight’s WDM solutions enable to extend multimode fiber capabilities beyond the 550m limitations of the 62.5µm (OM1) multimode fiber, to 2km or more depending on fiber quality and service type.
Multiplexer (Mux)
A multiplexer (mux) is an electronic device that combines multiple electronic input signals into a single output signal, while maintaining the integrity of each signal. In optical networks, multiplexers unite different data rates coded in different colors, into one signal that can be transported over single or dual fiber without degrading or altering the signals.
Muxponder
In WDM networks, muxponder technology aggregates multiple services into a single wavelength and then multiplexes them with other wavelengths into the same fiber. WDM technology increases fiber capacity by multiplexing multiple wavelengths with a dedicated service (GbE/10/40/100GbE LAN, SONET/SDH, Fibre Channel, HD/SD-SDI, OTU2/3, etc.) into a single fiber optic cable.

N

NGN
Next Generation Networking (NGN) is a commonly used term that describes packing voice, data, and video information into the same data packets using OTN encapsulation. An evolution in NGN architecture is taking place in the fields of telecommunication and access networks and will be deployed over the next few years. PacketLight solutions support NGN architecture and serve as a basis for developing such infrastructure.

O

OADM
An optical add-drop multiplexer (OADM) is a passive optical device used in WDM networks that allows to add and separate (drop) single or multiple wavelengths (channels) from a stream of light on a single fiber while letting the rest of the wavelengths continue through to the their destination.
Optical Amplifier
An optical amplifier is an optical module that amplifies the optical signal without first converting it to an electrical signal. They are important in fiber optic systems as they eliminate the need for repeaters in long distance fiber optic networks. Optical amplifiers can amplify 96 wavelengths simultaneously - the entire C-band spectrum. When long haul networks are built and there are multiple amplification sites along the link, the optical signal noise ratio (OSNR) is decreased and OTN encapsulation with FEC is used to transport the optical signal. The optical amplifiers gain can be adjusted to match the required amplification. There are two main types of optical amplifiers: Erbium-doped fiber amplifier (EDFA), and Raman amplifiers.
Optical Carrier (OC)
Optical carrier (OC) transmission rates are standardized specifications of transmission bandwidth for digital signals that can be carried on synchronous optical networking (SONET) networks.
Optical Transmitter
An optical transmitter is a device that sends data and information to a receiver through a fiber optic cable. A transmitter is usually connected to a power supply and is part of an active solution for fiber optic networks.
OTN
Optical transport network (OTN) is an optical mapping layer for a number of different services over the same common frame and rate structure, enabling a single optical transport network regardless of the native client signal. OTN relies on ITU-T G.709 digital wrapper specification to transparently encapsulate client signals and provide faster troubleshooting and superior SLA monitoring capabilities. OTN includes the additional benefit of forward error correction (FEC) to boost the network optical performance by a factor of at least 4 (6dB coding gain).

Q

QSFP+
Quad small form factor pluggable (QSFP) is an optical transceiver usually used for 40G links in data centers. The optical and electrical interfaces utilize 4 lanes of 10G. The optical interface can be 4 lanes over a single fiber (single mode) or 4 lanes over 4 fibers (multimode). QSFP+ supports short reach (SR), long reach (LR) and extender reach (ER) which provide cost/reach tradeoff. SR4 QSFP+ can reach 100m over multimode fiber and uses ribbon cable of 4 fibers for Tx and 4 fibers for Rx. LR4 QSFP+ can reach 10km over single mode fiber using dual LC fiber with internal mux/demux, multiplexing 4 wavelengths built inside the module. ER4 QSFP+ can reach 40km over single mode fiber using dual LC fiber with internal mux/demux multiplexing 4 wavelengths built inside the module. QSFP+ also is used to save panel space and can support 4 x 10G, replacing 4 x SFP+.
QSFP28
Quad small form factor pluggable 28 (QSFP28) is a hot-pluggable transceiver module designed for 100G data rate. It integrates 4 transmit and 4 receiver channels. The "28" refers to each lane carrying up to 28G data rate. Depending on the transceiver used, the QSFP28 typically operates at 4x25G for 100GbE but it will evolve to 2x50G or 1x100G over time as technology will progress. The QSFP28 has the same mechanical footprint and host board connector designs as the QSFP+ optical module so it can also support 40GbE or break out into 4x10G. There are three main types of QSFP28: LR4 for 10km, SR4 for 100m, and CWDM4 for 2km. The small footprint and low power consumption of the QSFP28 enable high density and capacity in 1U optical and switching systems, meaning cost reduction.

R

Raman Amplifier
Raman amplifier is a type of optical amplifier where the amplification is achieved by nonlinear interaction between the signal and a pump laser within an optical fiber. The Raman pump power is higher than in the Erbium-doped fiber amplifier (EDFA), which enables the signal to travel further (between 200km and 300km, depending fiber attenuation).
Radio Access Network (RAN)
Radio access network (RAN) is mostly used in mobile networks for transporting RF signals. Legacy RAN mobile networks largely utilize copper wiring to connect between the baseband unit (BBU) which creates the radio signal and the remote radio head (RRH) which converts the radio signal into an RF signal. With copper networks, both BBU and RRH are located in the same local cell unit in the field.
ROADM
A reconfigurable optical add-drop multiplexer (ROADM) is an optical device that allows wavelengths to be added or dropped from a WDM transport network without first converting them into electrical signals. The ROADM is remotely configurable and allows automatic power balancing.
Remote radio head (RH)
Remote radio head (RH) refers to a unit in a mobile operator's network which converts the radio signal into an RF signal. RH works together with the baseband unit (BBU) which creates the radio signal.

S

Single Mode (SM) Fiber
There are two types of fibers in optical networking today: single mode and multimode. Single mode (SM) optical fiber has a smaller core diameter, which forces all the energy in a light signal to travel in the form of a single mode, dramatically increasing the bit rate over distance. As it has a laser-based light source, SM fiber requires more expensive and precise electronics for data transport.
SONET & SDH
Synchronous optical networking (SONET) and synchronous digital hierarchy (SDH) are standardized multiplexing protocols that transfer multiple streams of bit over the optical fiber. SONET is a standard in the US and Canada, and SDH in the rest of the world. SONET rates are designated by optical carrier, OC-1/3/12/24/48/192. SDH rates are standardized in synchronous transport module. STM-1/4/16/64.
SR10 (100GBASE-SR10)
100GBASE-SR10 refers to 100Gb Ethernet. It is a port type of short range (SR) optic for multimode fiber. It uses 10 fibers, carrying 10Gb/s each for a distance of up to 100m. It is used only inside data centers, typically in the same rack. PacketLight SR10 modules support OTN OTU4 100G (although rarely required for this application).
STM
Synchronous transport module (STM) is the standard for transmitting SDH signal over fiber optic network. There are several levels of STM: STM-1, STM-4, STM-16 and STM-64.
Storage Area Network (SAN)
A storage area network (SAN) is a system of storage devices incorporated into a one data storage unit and transparently connected to the local area network (LAN). It can usually be accessed only by a system administrator.

T

Transponder
Optical transponders send and receive the optical signal from a fiber. A transponder is typically characterized by its data rate and the maximum distance the signal travels. Transponders convert the incoming optical signal into a pre-defined optical wavelength, by first converting the optical signal to an electrical signal and performing the 3R. The electrical signal is then used to drive the laser, which generates the optical signals. Transparent transponders implement 3R functionality for shorter range of up to 200km, and OTN transponders add the encapsulation of the service into OTN with FEC, enabling the signal to be transported over thousands of kilometers without the need for regenerators.

W

WDM
Wavelength division multiplexing (WDM) is a technology of optical networking used to combine multiple optical signals into one and transfer it over single fiber. WDM technology uses multiplexing and demultiplexing to achieve the desired effect. WDM technology allows to significantly decrease the CAPEX and OPEX of optical networking and increase capacity. It also allows for bi-directional communication. There are two types of WDM technology: coarse WDM (CWDM) and dense WDM (DWDM)

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