Topic 4 Flashcards
(17 cards)
What is the purpose of the physical layer?
Accepts a complete frame from the Data Link Layer and encodes it as a series of signals that are transmitted to the local media.
Transports bits across the network media.
What are the functions of encoding and signaling?
Encoding converts the stream of bits into a format recognizable by the next device in the network. The signaling method is how the bit values, ‘1’ and ‘0’ are represented on the physical medium.
What is bandwidth?
The capacity at which a medium can carry data.
What is latency?
The amount of time, including delays, for data to travel from one given point to another.
What is throughput?
The measure of the transfer of bits across the media over a given period of time.
What is overhead?
The amount of data traffic required for establishing sessions, acknowledgments, and encapsulation.
What is goodput?
The measure of usable data transferred over a given period of time.
Goodput = Throughput - Overhead
Define EMI / RFI.
EMI and RFI signals can distort and corrupt the data signals being carried by copper. Sources of EMI and RFI include fluorescent lights or electric motors.
What is crosstalk?
A disturbance caused by the electric/magnetic fields of a signal on one wire to the signal in an adjacent wire, resulting in hearing part of another voice conversation from an adjacent circuit.
Why is it important to twist the wire pairs in a UTP cable?
Twisting opposing circuit pair wires together to reduce crosstalk. Twisted pairs protect the signal from interference.
When is a straight-through cable used?
Between devices at different layers.
When is a crossover cable used?
Between devices at similar layers.
When is a rollover cable used?
For console connection to a router/switch port.
What are the four areas of concern in a wireless network?
- Coverage area.
- Interference.
- Security.
- Shared medium.
List three wireless standards and their applications.
- Wi-Fi (IEEE 802.11) - Wireless LAN (WLAN) technology.
- Bluetooth (IEEE 802.15) - Wireless Personal Area network (WPAN) standard.
- WIMAX (IEEE 802.16) - Uses a point-to-multipoint topology to provide broadband wireless access.
- Zigbee (IEEE 802.15.4) - Low data-rate, low power-consumption communications, primarily for Internet of Things (IoT) applications.
What are the four areas of concern in a wireless network?
- Coverage area.
- Interference.
- Security.
- Shared medium.
List three wireless standards and their applications.
- Wi-Fi (IEEE 802.11) - Wireless LAN (WLAN) technology.
- Bluetooth (IEEE 802.15) - Wireless Personal Area network (WPAN) standard.
- WIMAX (IEEE 802.16) - Uses a point-to-multipoint topology to provide broadband wireless access.
- Zigbee (IEEE 802.15.4) - Low data-rate, low power-consumption communications, primarily for Internet of Things (IoT) applications.
