Here are some of the most commonly used abbreviations you should know in CCNA and in common. Just bookmark this page in case you need it again:

*(CSMA/CD) carrier sense multiple access collision detect
*(OUI) organizational unique identifier
*(GBIC) gigabit interface converter
*(DTE) data terminal equipment
*(DCE) data communications equipment
*(NIC) network interface card
*(NOS) network operating system
*(VoIP) voice over IP
*(QoS) quality of service

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