Wireless Networks Flashcards
CSMA/CA is used in…
Carrier Sense Multiple Access with Collision Avoidance
Used in wireless networks, while CSMA/CD is used in wired networks
CSMA/CD is used in…
Carrier Sense Multiple Access with Collision Detection
Used in wired networks, while CSMA/CA is used in wireless networks
What is IBSS
Independent Basic Service Set
Also called ad hoc
A wireless network in which two or more wireless devices connect directly without using an AP
What is BSS
Basic Service Set
Wireless infrastructure in which clients connect to each other via an access point
What is ESS
Extended Service Set
Connects BSS’s to each other via a switch stack over a wired network.
WGB/uWGB
Universal Workgroup Bridge is an 802.11 standard which allows a device to be bridge onto a wireless network (like a wifi adapter)
WGB is a Cisco-proprietary version of a uWGB
DS
Distributed System
The upstream wired network that connects the wireless network to the MDF
What are the 3 802.11 connection states?
Not authenticated, not associated
Authenticated, not associated
Authenticated, and associated
What is the authentication process?
A client sends a probe request to learn about what APs and BSSs are available
An AP sends a probe response
A client sends a authentication request (password)
AP authenticates it
Probe sends association request
AP sends association response
What are the 802.11 message types?
Management: Beacon, Probe request, Authentication, Association, etc.
Control: Used to control access to the medium (RF) Assists with delivery of management and data frames
RTS, CTS, ACK, etc. CSMA/CD
Data: Used to send actual data packets
Lightweight AP is also called
split-MAC architecture
Tunnels created between the AP and WLC use port#:
UDP 5246/7
Bridge/Mesh mode
A lightweight AP deployment. Can be a dedicated bridge between sites, even over long distances. A mesh can be made between the access points
WEP uses which encryption method?
RC4
What are the three main entities of 802.1x?
Supplicant: The device that wants to connect to the network
Authenticator: The device that provides access to the network
Authentication Server (AS): The device that receives client credentials and permits/denies access
How does LEAP work?
Lightweight Extensible Authentication Protocol
Both clients and server exchange challenge phrases and use those to authenticate. It is Dynamic, meaning the keys frequently change.
How does EAP-FAST work?
A PAC (Protected Access Credential) is generated and passed from server to the client.
A secure TLS tunnel is established between the client and auth server
In the tunnel, the client and server communicate to authenticate the client.
EAP-TLS
EAP-TLS requires every client on the AS to have a certificate
Most secure, but most difficult to implement
How does PEAP (Protected EAP) work?
Establishes a TLS tunnel
Instead of PAC, it uses a digital certificate to establish a tunnel
Uses MS-CHAP to authenticate in the tunnel
What is a MIC
Message Integrity Check
What is TKIP
Temporal Key Integrity Protocol
Used as a solution to WEP. More secure
Used in WPA1
What is CCMP
Counter/CBC-MAC Protocol)
Used in WPA2
Uses AES
Uses CBC-MAC (Cipher Block Chaining Message Authentication Code) is used as a MIC
What is GCMP
(Galois/Counter Mode Protocol)
AES counter mode for encryption
More secure and efficient than CCMP
Used in WPA3
GMAC for MIC
