Week 5 Flashcards
Baud rate
A measurement of how many bits can be passed across a phone line in a second
Broadband
Any connectivity technology that isn’t dial up internet
T-carrier technologies
Originally invented by AT&T in order to transmit multiple phone calls over a single link
How fast can a T1 line transmit data?
1.54 Mb/s
Cable modem termination system (CMTS)
Connects lots of different cable connections to an ISPs core network
Optical network terminator (ONT)
Converts data from protocols the fiber network can understand, to those that more traditional, twisted-pair copper networks can understand
Wide area network
Acts like a single network, but spans across multiple physical locations
What layer do WANs draw a lot from?
Data link layer
Area between site and an ISP
Local loop
802.11 families
Make up the set of standards for WiFi
What kind of waves do wireless networks communicate through?
Radio
Frequency band
A certain section of the radio spectrum that’s been agreed upon to be used for certain communications
What radio frequency does FM radio operate under in North America?
Between 88 and 108 MHz
What are the common Wi-Fi bands?
2.4 GHz and 5 GHz
What are the most common 802.11 specifications IT support deals with?
802.11b, 802.11a, 802.11g, 802.11n, 802.11ac
What layers do 802.11 standards typically deal with?
Physical and data link layers
Frame control field
How many octets?
Contains fields describing how the 802.11 frame should be processed
2
Duration field
Octets?
Specifies how long the frame is, thereby letting receiver know how long to listen to the transmission
2
How many address fields in a 802.11 frame?
4
Wireless access point
A device that bridges the wireless and wired portions of a network
What do each of the address fields in an 802.11 frame contain
Source MAC address, destination MAC address, Transmitter address, receiver address
Receiver address
MAC address of the device that should receive the frame
Transmitter address
MAC address of whatever has just transmitted the frame
How long is a single address field
6 octets , because they only contain MAC addresses
Where is the sequence field in the 802.11 field located?
Between the transmitter and receiver address field
What are the last two fields in the 802.11 frame?
Payload, then frequency checksum value
Ad-Hoc network
Wireless network where nodes speak directly to each other
Wireless LANS
One or more wireless access points act as a bridge between a wireless and a wired network
Mesh networks
Hybrid of ad-hoc and WLAN network
Channels
Individual, smaller sections of the overall frequency band used by a wireless network
Wired Equivalent Privacy (WEP)
An encryption technology that provides a very low level of privacy
How many bits in a WEP encryption key?
40
How many bits in WiFi Protected Access?
128
What is the most common wireless encryption algorithm? How many bits does its key have?
WPA2
256
MAC filtering
You configure your access points to only allow for connections from a specific set of MAC addresses belonging to devices you trust
