Section 11: Wireless Networks

Question 1

WiFi IEEE Standard

Answer 1

802.11 (Standard for Local Area Networks)

Question 2

AdHoc Mode

Answer 2

▪ Wireless devices communicate directly with each other without the need for a centralized access point
▪ Peer-to-Peer connections

Question 3

Infrastructure Mode

Answer 3

▪ Wireless devices communicate with other wireless or wired devices through a wireless router or access point

Question 4

AP or WAP

Answer 4

Access Point or Wireless Access Point (Layer 1)
▪ Extends wired LAN into the wireless domain
● Does not interconnect two networks (not a router)
● Functions as a hub
▪ Connects wired LAN and wireless devices into the same subnet
▪ All clients on an access point are on a single collision and broadcast domain

Question 5

Wireless Router

Answer 5

▪ Gateway device and base station for wireless devices to communicate with each other and connect to the Internet
▪ Often combines many features into one device:
● Wireless Access Point (WAP or AP)
● Router
● Switch
● Firewall
● Fiber, Cable, or DSL modem

Question 6

WLAN IBSS

Answer 6

Independent Service Set - No access points. AdHoc Mode.

Question 7

WLAN BSS

Answer 7

Basic Service Set - Only one AP connected to the network. (Infrastructure Mode)

Question 8

WLAN ESS

Answer 8

Extended Service Set - Multiple APs connected to network. (Also Infrastructure Mode.) (Same Wirless Network Name)

Question 9

Wireless Mesh Topology

Answer 9

▪ May not use a centralized control
▪ Uses WiFi, Microwave, Cellular, and more

Question 10

Spread Spectrum Wireless Transmission Terms to know for exam

Answer 10

▪ Direct-Sequence Spread Spectrum (DSSS)
▪ Frequency-Hopping Spread Spectrum (FHSS)
▪ Orthogonal Frequency-Division Multiplexing (OFDM)
▪ Only DSS and OFDM are commonly utilized in today’s WLANs

Question 11

Which 2.4 GHz channels avoid overlapping frequencies for b/g/n networks?

Answer 11

1, 6 and 11 (Provides enough separation to keep 20MHz of use and fit within the 72MHz of allowable spectrum.)

Question 12

What is the 5GHz spectrum feature that allows for combining channels?

Answer 12

Channel Bonding
▪ Allows you to create a wider channel by merging neighboring channels into one

Question 13

802.11a: Operating band / max bandwidth?

Answer 13

5 GHz / 54 Mbps

Question 14

802.11b: Operating band / max bandwidth?

Answer 14

2.4 GHz / 11 Mbps

Question 15

802.11g: Operating band / max bandwidth?

Answer 15

2.4 GHz / 54 Mbps

Question 16

802.11n: Operating band / max bandwidth?

Answer 16

2.4 and 5 GHz / 150 Mbps and 600 Mbps (MIMO)
(aka Wi-Fi 4)

Question 17

802.11ac: Operating band / max bandwidth?

Answer 17

5 GHz / 3 Gbps (MU-MIMO)
(aka Wi-Fi 5)

Question 18

802.11ax: Operating band / max bandwidth?

Answer 18

2.4, 5, and 6 GHz / 9.6 Gbps (MU-MIMO)
(aka Wi-Fi 6)

Question 19

Wireless Security: Four things to know for exam.

Answer 19

Open = No security/protection
WEP = Initialization Vector (The flaw with WEP, Weak)
WPA = TKIP (Replaced the initialization vectors) and RC4 (Encryption - Weak)
WPA2 = CCMP-(Integrity Protocol); AES-(Encryption Mechanism)

Question 20

EAP

Answer 20

Extensible Authentication Protocol - Authentication using 802.1x (3 Modes)
▪ EAP-FAST - Flexible Authentication via Secure Tunneling
▪ EAP-MD5
▪ EAP-TLS

Question 21

MAC Filtering

Answer 21

For exam considered a reasonable security measure. Not so much in the real world.

Question 22

NAC

Answer 22

Network Access Control - Permits/denies access based on devices characteristics.
▪ Checks the OS and antivirus version of client

Question 23

Captive Portal

Answer 23

▪ Web page that appears before the user is able to access the network resources
▪ Webpage accepts the credentials of the user and presents them to the authentication server

Question 24

Geofencing

Answer 24

▪ GPS or RFID defines boundaries which can be active or passive
▪ Device can send alerts if it leaves area
▪ Network authentication can use it to determine access

Question 25

Disable SSID Broadcast

Answer 25

Server Set Identifier
▪ Configures an AP to not broadcast the name of the wireless LAN
(Minor security feature because it can be easily determined. But, can be a layer when using other security features.)

Question 26

Rogue Access Point

Answer 26

▪ Malicious users set up an AP to lure legitimate users to connect
▪ Can then capture all the packets (data) going through the rogue access point