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EXFO Glossary

C (browse from .......... to)
C Form-Factor Pluggable (CFP)...............CCSCD...............Class of Service (CoS)CLEC...............Connectivity fault management (CFM)Connector...............CSMA/CDCSPAT...............Cyclic Redundancy Check (CRC)
C Form-Factor Pluggable (CFP)Carrier Ethernet 2.0 (CE 2.0)CAS
Call before You Dig (CBUD)Carrier Ethernet TestingCBR
CAPCarrier SenseCBS
CAPEXCarrier Serving Area (CSA)CC
Capital Expenditure (CAPEX)Carrier-Sense Multi-Access with Collision Detection (CSMA/CD)CCF
CarrierCarrier-Sense Multiple-Access (CSMA)CCS
Carrier Ethernet 1.0 (CE 1.0)Carrier-Sense Multiple-Access with Collision Avoidance (CSMA/CA)
from C Form-Factor Pluggable (CFP)... to CCS

C Form-Factor Pluggable (CFP)

A larger SFP to support 100G; it has a "transmit" side and a "receive" side.

Call before You Dig (CBUD)

A utility marker and label with a phone number that notifies construction workers on where to obtain exact location information for local underground cables. Also known as CBUD.


Acronym for: Carrierless amplitude phase


Acronym for: Capital expenditure

Capital Expenditure (CAPEX)

What companies spend on material (vs. OPEX, which is what they spend on Human Resources).


An electromagnetic wave or alternating current that is modulated to carry signals in radio, telephonic, or telegraphic transmission.

Carrier Ethernet 1.0 (CE 1.0)

MEF’s first generation standardized carrier-class Ethernet services over one provider’s network.

Carrier Ethernet 2.0 (CE 2.0)

MEF’s second generation standardized carrier-class Ethernet services.  Carrier Ethernet 2.0 enables multiple classes of service and manageability over interconnected providers' networks.

Carrier Ethernet Testing

The testing of Carrier Ethernet, which is the extension of Ethernet that enables service providers to provide premium Ethernet services. the goal is to tap into the cost-effectiveness of Ethernet without sacrificing the benefits of connection-oriented, time-domain multiplexing solutions such as SONET/SDH. However, Ethernet performance criteria are more difficult to prove, and demonstrating performance availability, transmission delay, link burstability and service integrity cannot be done precisely with only a single ping command.

Carrier Sense

A method of detecting the presence of signal activity on a common channel. With Ethernet, a method of detecting whether another station is transmitting.

Carrier Serving Area (CSA)

The area served by a local-exchange carrier, regional Bell operating company or telephone company. CSAs often use digital-loop carrier (DLC) technology.

Carrier-Sense Multi-Access with Collision Detection (CSMA/CD)

A network access method used by Ethernet in which a station listens for traffic before transmitting. If two stations transmit simultaneously, a collision is detected and both stations wait a brief time before attempting to transmit again. So called because it a) allows multiple stations to access the broadcast channel at will, b) avoids contention via carrier sense and deference, and c) resolves contention via collision detection and retransmission.

Carrier-Sense Multiple-Access (CSMA)

A probabilistic media access control (MAC) protocol in which a node verifies the absence of other traffic before transmitting on a shared transmission medium, such as an electrical bus, or a band of the electromagnetic spectrum.

Carrier-Sense Multiple-Access with Collision Avoidance (CSMA/CA)

Used to improve the performance of CSMA by attempting to be less "greedy" on the channel. If the channel is sensed busy before transmission then the transmission is deferred for a "random" interval. This reduces the probability of collisions on the channel.


Acronym for: Channel associated signaling


Acronym for: Constant bit rate


Acronym for: Committed burst size


Acronym for: Cross connect


Acronym for: Charging collection function


Acronym for: Common channel signaling