Vol 1 Part 8: Fundamentals of Wireless Networks Flashcards
What is the standard that wireless devices must adhere to?
802.11
Access Points operate in what mode, and what does this mode offer?
Infrastructure mode. It offers services necessary to form the infrastructure of a wireless network.
What is a basic service set?
The collection of devices that can communicate with each other in your wireless network.
What is the Service Set Identifier (SSID)?
The name of the wireless network
What is the basic service set identifier (BSSID)
?
The BSS ambassador (your access point)
Membership with the BSS is called a what?
An association
What must a host device send to the access point in order to join the basic service set?
An association request
The 802.11 standard refers to upstream wired ethernet as the BLANK for the wireless basic service set.
Distribution system (DS). This is essentially the connection that interconnects the wireless to the wired network.
The AP is in charge of mapping a BLANK to a BLANK
a VLAN to an SSID
What is an extended service set (ESS)?
Multiple APs that cover different geographic locations that are all interconnected by a switched structure
With respect to a wireless network, what is roaming?
The concept of moving to a different AP within the ESS
What is an independent basic service set (IBSS)?
Two or more wireless clients that can communicate directly with each other without the need for an access point. This is also known as an Ad-Hoc network, and is impromptu, scaling poorly after 8 to 10 devices are on the IBSS.
What is a repeater, what happens to signal that flows through a repeater, and how has this issue been remedied?
A repeater is configured to relay signal coverage to another area, useful when trying to get coverage to an area where the AP cannot reach. Throughput is halved when using a repeater, as the channel is now twice as long. To remedy this, some repeaters have multiple transceivers.
What is a workgroup bridge (WGB)?
An adapter used to bring in a device that only supports a wired connection into a wireless network
What are the two types of WGBs and what do they do?
Universal workgroup bridge (uWGB)- it allows a single wired device to be bridged
Cisco Workgroup Bridge- a cisco proprietary variant that allows multiple wired devices to connect to a wireless network.
What is a mesh network in regards to a wireless network?
A mesh of access points that leverage dual radios, with one channel in range of one frequency and another channel in range of a different range of frequencies. The BSS is on one channel, and the client traffic is bridge from AP to AP, kindof like RETRANS!
What are the two frequencies utilized by wireless networks?
2.4Ghz and 5 Ghz.
A range of frequencies is known as a what?
A band
What channels are used in wireless networks in order to avoid overlap?
1, 6, and 11
What are the pros and cons of the 2.4Ghz band vs the 5Ghz band?
2.4 has better range and barrier penetration
5 has more channels, meaning less overlap, and is faster, but has less range and less barrier penetration
Which wireless standard has very high throughput and does not use the 2.4 Ghz range?
802.11ac
Autonomous Access Points can have multiple BLANK residing in different BLANK
SSIDs residing in different VLANs
Cisco Meraki is a cloud based software that allows a network engineer to do what?
Manage the wireless, switched, and security networks through report generation, AP management, performance monitoring, and more.
Cisco Meraki will instruct APs to make changes if BLANK or BLANK is detected
interference or rogue access points
When functions of an AP are divided, the AP becomes a BLANK
A lightweight access point that only performs real-time functions
What is a wireless LAN controller (WLC)?
A device used to control the management functions on a wireless network
When the access points and a wireless LAN controller are implemented in order to divide labor on the network, the network is referred to as a BLANK
a split-MAC architecture network
The AP and WLC use this protocol in a split-MAC network
Control and Provisioning of Wireless Access Points Tunneling Protocol (CAPWAP)
CAPWAP has two separate tunnels. What are they, and what do they do?
CAPWAP Control Messages- carries exchanges to configure APs and manage it. This tunnel is authenticated and encrypted for security, forcing the AP to only communicate with the appropriate WLC
CAPWAP Data- sends packets to and from wireless clients on the access point. This data is not encrypted by default, and can be encrypted using Datagram Transport Layer Security (DTLS).
Each AP must BLANK with the WLC using BLANK
Authenticate with the WLC using digital certificates
Placing the WLC in a central location is referred to as BLANK or BLANK
unified or centralized WLC deployment
Placing the WLC in a central position in a data center in a private cloud is known as BLANK
cloud-based WLC deployment
What is meant by open authentication in regards to a wireless client?
No credentials are needed to join the network. Think of a Wi-Fi hotspot at Starbucks.
WEP uses what kind of encryption? Why is WEP considered weak?
RC4 cipher encryption. It is weak because the key used to encrypt and decrypt is the same and it is shared between the sender and receiver ahead of time.
802.1x, also known as the Extensible Authentication Protocol (EAP) does what in regards to authentication on a wireless network?
It requires a dedicated server used for authentication, usually a Radius server, that takes the client (supplicant) and the authenticator (network device giving access) and compares the credentials of the client based on its database.
In a WLAN, the WLC becomes an authenticator/middle man. What are the 4 methods of authentication in this configuration?
- LEAP
- EAP-FAST
- PEAP
- EAP-TLS (most secure and utilizes a public key infrastructure)
What is the temporal key integrity protocol (TKIP)?
A security protocal that authenticates using a message integrity check (MIC), time stamps, the client’s MAC address, and a key mixing algorithm.
What kind of encryption does the Counter/Chain Block Cipher-MAC protocol (CCMP) use, what are it’s advantages over TKIP, and what kind of security is this protocol used with?
CCMP uses AES counter mode encryption, allowing it to be more secure than TKIP. CCMP is used with WPA2.
What kind of encryption does Galois/Counter Mode Protocol (GCMP) use and what kind of security is this protocol used with?
GCMP uses AES counter mode encryption. GCMP is used in WPA3.
How do you configure a management IP on a Cisco Wireless LAN controller?
- Console Connection
- Web based GUI on HTTP/HTTPS
- SSH
REMEMBER! Authentication on a WLC can be either local or AAA!
What is Link Aggregation Group (LAG)?
EtherChannel for WLCs.
What are the 4 types of ports on a WLC?
- Service
- Distribution
- Console
- Redundancy
What is the management interface used for on a WLC?
Normal management traffic such as user authentication and the termination of CAPWAP tunnels.
What is the virtual interface used for on a WLC?
IP address facing wireless clients when the controller is relating client DHCP, authenticating, and roaming
What is a service Port Interface used for on a WLC?
Out of Band Management
What is the dynamic interface used for on a WLC?
To connect a VLAN to a WLAN
What are the 7 steps to configuring a WLAN?
- Define the WLAN on the WLC
- Set up a RADIUS server for AAA
- Create a dynamic interface
- Pick your security types
- Configure your Quality of Service settings
- Advanced WLAN settings as needed
- Finalizing the WLAN configuration
