Module 30 Explaining Wireless Fundamentals
Which three channels in the 2.4-GHz band are non-overlapping?
1,6,11
What type of VLANs are required with WLANs
1. Management VLAN-is for the WLC management interface configured on the WLC 2. AP VLAN-use this VLAN to obtain IP address through DHCP and send their discovery request to the WLC management interface using those IP addresses. 3. Data VLAN-
What are the two main radio waves frequencies with wireless technology?
2.4 and 5Ghz
How wide are the 2.4-GHz ISM band channels?
22Mhz
How many available channels in 2.4Ghz for United States, Europe and Japan
22Mhz USA-11(1,6,11) Europe-13(1,6,11) Japan-14(1,6,11,14)
What are the wide channel for 5Ghz?
40,80,160MHz
Which IEEE 802.11 standard operate at 5Ghz
802.11a 802.11ac 802.11n 802.11ax
Which wireless solution is used for branch and remote office deployments and eliminates the need for a WLC on each location?
AP in FlexConnect mode
Why do clients and APs will need to create different subnets in a WLAN?
To break up the broadcast domain and segment for security and routing.
Is a network that exists within a relatively small area and connects electronic devices such as desktop computers, printers, scanners, fax machines, and notebook computers.
WPAN
Which wireless topology provides host connectivity within a maximum of 10 meters?
WPAN
Wi-Fi Direct is an example of which type of wireless topology?
WPAN
Infrastructure mode characteristic:
• The AP functions as a translational bridge between 802.3 wired media and 802.11 wireless media. • Wireless is a half-duplex environment. • A basic service area (BSA) is also called a wireless cell. • A BSS is the service that the AP provides.
Which three IEEE 802.11 amendments specify the 5-GHz frequency band for Wi-Fi operation? (Choose three.)
802.11n 802.11a 802.11ac
Which IEEE 802.11 standard operate at both 2.4Ghz and 5Ghz?
802.11n 802.11ax
On a wireless network the most secured way for each user to have its own identity is by what type of authentication?
802.1X
What is the central device in the BSA or wireless cell?
AP
Radio waves are characterized by three properties?
Amplitude -is referred to as the Power of the signal itself. Wavelength -is the distance from one peak in the wave to the next. Frequency -is how often a wave will oscillate per second measured in Hertz [Hz]. Wavelength is inversely proportional to Frequency.
The MAC address that derived from the radio MAC address and associated with an SSID is called what?
Basic Service Set Identifier (BSSID). The BSSid identifies the BSS that is determined by the AP coverage area.
What is Control and Provisioning of Wireless Access Points?
CAPWAP is an open protocol that enables a WLC to manage a collection of wireless APs. A CAPWAP tunnel uses the following UDP port numbers: Control plane uses UDP port number 5246 Data plane uses UDP port number 5247
Which device in a split MAC architecture is responsible for 802.11 association and reassociation?
Cisco WLC
What components wireless networks usually consist of:
Clients with wireless adapter • APs, which are Layer 2 devices whose primary function is to bridge 802.11 WLAN traffic to 802.3 Ethernet traffic. APs can have internal (integrated) or external antennas to radiate the wireless signal and provide coverage with the wireless network. • APs can be standalone or centralized: • Standalone (autonomous) APs, managed individually • Centralized APs, managed by a Cisco WLC • (Optional) A Cisco WLC that presents a central point for AP management, configuration of APs, and user traffic termination for centralized APs.
what type of interference does things like electrical equipment, such as generators, construction tools, and microwaves cause?
Electromagnetic interference
When using LAG on a switch connected to a WLC, which two options would be configured on the switch port? (Choose two.
Etherchannel mode on and trunk mode.
When the distribution system link two APs or two cells what is it called?
Extended Service Set (ESS).
When using a global AAA server there must be ______________ reachability between the WLC and the AAA server.
IP
How is the Service Set Identifier advertised?
In Wi-fi packets that are sent from the client, and SSID are advertised in Wi-Fi responses that are sent by the APs.
What is the Infrastructure Mode?
In the infrastructure mode design, an AP is dedicated to centralizing the communication between clients.
What is a Basic Service Set in an Ad Hoc network is called?
Independent Basic Service Set (IBBS).
What is a workgroup bridge (WGB)?
Is an AP that is configured to bridge between its Ethernet and wireless interfaces.
What is A Basic Service Set BSS?
Is the area within which a computer can be reached through its wireless connection
What is the most common wireless network?
Is the centralized APs, or lightweight architecture.
What is the characteristic of an ad hoc network:
It creates an Independent Basic Service Set (IBSS). • It exists when two wireless devices communicate. • It contains a limited number of devices because of collision and organization issues.
Which statement correctly describes an ad hoc wireless network?
It is referred to as an IBSS
What is DHCP Option 43?
It is used to identify the vendor type and configuration of a DHCP client. It can be used to include the IP address of the Cisco WLC interface that the AP is attached to.
The AAA server Functionality can be provided by?
Locally by a Cisco WLC Globally by an AAA server
What are Multiple Basic Service Set Identifier(MBSSID)?
MBSSIDs are basically virtual APs. All of the configured SSIDs share the same physical device, which has a half-duplex radio. As a result, if two users of two SSIDs on the same AP try to send a frame at the same time, the frames will collide. Even if the SSIDs are different, the Wi-Fi space is the same. Using MBSSIDs is only a way of differentiating the traffic that reaches the AP, not a way to increase the capacity of the AP.
An administrator can create several SSIDs on the same AP. The criteria by which a station is allowed on one or the other SSID will be different, but the AP will be the same. What is this configuration an example of?
Multiple Basic SSIDs
What are some of the wireless antenna types used in wireless devices?
Omnidirectional Directional Patch
What is the IPv6 version of Option 43
Option 52
Which DHCP option is used to send the DNS server IPv4 address to the client?
Option 6
A DHCP server can be configured with various options that are included inside the DHCP packet. If you have configured your DHCP server to provide with these two options. Both clients and APs can obtain this information from the DHCP option
Option 6 and 15
What option or method you could use when Aps and WLCs are on seperated subnets (no common broadcast domain)?
Options 43
What can large businesses use to view the status of the Cisco WLC, or to control it from a remote management station.
SNMP
Which information is used by a Cisco WLC to decide which VLAN to assign to a client?
SSID
To roam between different APs within a network the APs must share the same network name. what is that name called?
Service Set Identifier (SSID)
What size business can use HTTPs and manage their Cisco WLCs directly through the GUI.
Small to midsize businesses
What is split MAC?
Split MAC is an architecture for the Control and Provisioning of Wireless Access Points (CAPWAP) protocol defined in RFC 5415.
In a network, all wireless-capable devices are called what?
Stations, end devices are oftern called client station.
WLC and APs are usually connected to what?
Switches
By associating each SSID to a different VLAN you can group users on what?
The ethernet segment the same way that they were grouped in the WLAN.
What is Wi-Fi direct
The intent is the creation of peer-to-peer Wi-Fi connections between devices, without the need for an AP. It is another example of a WPAN.
The IEEE 802.11 header of a wireless frame typically has how many MAC addresses
The receiver is identified by MAC Address 1 The transmitter is identified by MAC Address 2. The receiver uses MAC Address 3 for filtering purposes MAC Address 4 is only present in specific designs in a mesh network.
What does the centralized or lightweight architecture allows?
The splitting of 802.11 functions between the controller-based AP, which processes real-time portions of the protocol, and the wLC which manages items that are not time-sensitive.
Which two ports must a firewall allow for CAPWAP operations? (Choose two.)
UDP 5246 UDP 5247
What are the two ways of implementing DHCP:
Using an internal DHCP server on the Cisco WLC. • WLCs contain an internal DHCP server. This server is typically used in branch offices that do not already have a DHCP server. • DHCP Option 43 is not supported on the WLC internal server. Therefore, the AP must use an alternative method to locate the management interface IPv4 address of the WLC, such as local subnet broadcast or DNS.
Assume that you have an autonomous AP that is connected to a switch. Based upon the following configuration, which statement correctly describes the implementation? switch# configure terminal switch(config)# interface GigabitEthernet1/0/3 switch(config-if)# description AP2 switch(config-if)# switchport mode trunk switch(config-if)# switchport trunk native vlan 12 switch(config-if)# switchport trunk allowed vlan 12,14
VLAN 14 is for client traffic.
In contrast to WPAN this network provide more robust wireless network connectivity over a local area, up to approximately 100 m (328 feet) between an AP and associated clients.
WLAN
VLANs provide an ideal way of separating users on different ______________ when they access the wired side of the network.
WLAN SSID
Wi-Fi compatible devices can connect to a network or the internet via?
WLAN or AP
Which device in a centralized wireless solution associates the SSID with a VLAN?
WLC
What does DHCP Option 43 provide for in a Cisco WLAN?
WLC IP address
This is a wireless communications network that covers a large geographic area, such as a city or a suburb. In this type of area, the wireless signal often provides a point-to-point or point-to-multipoint backbone.
WMAN
Which wireless technology provides host connectivity within a large geographic area, such as a city or a suburb?
WMAN
Network Time Protocol is used in a WLAN, much like it is in LANs. How does NTP play an important role in the AP join process?
When an AP is joining a Cisco WLC, the WLC verifies the AP embedded certificate and if the date and time that are configured on the WLC precede the creation and installation date of certificates on the AP, the AP fails to join the WLC. Therefore the WLC and AP should synchronize their time using NTP.
What does Wi-Fi direct device include which makes it easy to set up a connection and enable security protections.
Wi-FI Portected Setup (WPS)
What are some wireless topologies?
Wireless Personal Area Network Wireless Local Area Network Wireless Metropolitan Area Network
What is computer to computer wireless communication is most commonly referred to?
ad hoc network, IBSS, or peer-to-peer (wireless) network.
What is an AP that function as a standalone element without a Cisco WLC?
autonomous mode
Which AP usually connects to a switch access port (nontrunking)?
centralized AP (local mode)
How is the initial WLC configuration is accomplished with what two ways?
console port and CLI or WLC web interface.
Which device does not emit radio frequencies but can still interfere with wireless network operation?
fluorescent light
Any waves traveling through a medium are affected by phenomena such as:
• Absorption: Signal power degrades when moving from a less dense to a higher dense medium (moving through air and then passing through a solid object in its path). • Reflection: Radio waves partially bounce off objects that they come in contact with. • Refraction: Some mediums, such as liquids, will alter the path that the wave is taking as it passes through.
What are the feature of Split MAC?
• Centralized tunneling of user traffic to the WLC (data plane and control plane) • Systemwide coordination for wireless channel and power assignment, rogue AP detection, security attacks, interference, and roaming
What are the AP centralized modes of operation?
• Local mode, which is the default operational mode of APs when connected to the Cisco WLC. When an AP is operating in local mode, all user traffic is tunneled to the WLC, where VLANs are defined. • FlexConnect mode, which is a Cisco wireless solution for branch and remote office deployments, to eliminate the need for WLC on each location. In FlexConnect mode, client traffic may be switched locally on the AP instead of tunneled to the WLC.
