Glossary of Key Terms

?

The help command that can be used at any prompt in the command line interface for Cisco IOS Software

“Hello” Packets

Used in the OSPF protocol to verify that the links are still communicating

10GBASE-T

10Gbps over twisted-pair copper cable

6to4 Prefix

A technique that enables IPv6 hosts to communicate over the IPv4 Internet

Absorption

Light interaction with the atomic structure of the fiber material; also involves the conversion of optical power to heat

Access Control Lists (ACLs)

A basic form of firewall protection

Access Point

A transceiver used to interconnect a wireless and a wired LAN

ACK

Acknowledgement packet

ACR

The attention-to-crosstalk ratio measurement compares the signal level from a transmitter at the far end to the crosstalk measured at the near end. A larger ACR indicates that the cable has a greater data capacity and also indicates the cable’s ability to handle a greater bandwidth. Essentially, it is a combined measurement of the quality of the cable. A higher ACR value (dB) is desirable.