Wireless

Benefits of Wireless

A Wireless LAN (WLAN) is a type of wireless network that is commonly used in homes, offices, and campus environments.

WLANs make mobility possible within the home and business environments

Wireless Standard

Radio Frequencies

All wireless devices operate in the range of the electromagnetic spectrum. WLAN networks operate in the 2.4 and 5 GHz frequency bands.

  • 2.4 GHz (UHF) – 802.11b/g/n/ax
  • 5 GHz (SHF) – 802.11a/n/ac/ax

AP Categories

  • Autonomous APs – Standalone devices configured through a command line interface or GUI. Each autonomous AP acts independently of the others and is configured and managed manually by an administrator.

AP Categories

  • Controller-based APs – Also known as lightweight APs (LAPs). Use Lightweight Access Point Protocol (LWAPP) to communicate with a LWAN controller (WLC). Each LAP is automatically configured and managed by the WLC.

Wireless Antennas

  • Omnidirectional – Provide 360-degree coverage. Ideal in houses and office areas.
  • Directional – Focus the radio signal in a specific direction. Examples are the Yagi and parabolic dish.
  • Multiple Input Multiple Output (MIMO) – Uses multiple antennas (Up to eight) to increase bandwidth

Ad hoc mode

Used to connect clients in peer-to-peer manner without an AP

Infrastructure mode

Used to connect clients to the network using an AP

Tethering

Variation of the ad hoc topology is when a smart phone or tablet with cellular data access is enabled to create a personal hotspot

Basic Service Set (BSS)

  • Uses single AP to interconnect all associated wireless clients.
  • Clients in different BSSs cannot communicate.

Extended Service Set (ESS)

  • A union of two or more BSSs interconnected by a wired distribution system.
  • Clients in each BSS can communication through the ESS

CSMA/CA

WLANs are half-duplex and a client cannot “hear” while it is sending, making it impossible to detect a collision.
WLANs use carrier sense multiple access with collision avoidance (CSMA/CA) to determine how and when to send data.
A wireless client does the following:
1.Listens to the channel to see if it is idle, i.e. no other traffic currently on the channel.
2.Sends a ready to send (RTS) message the AP to request dedicated access to the network.
3.Receives a clear to send (CTS) message from the AP granting access to send.
4.Waits a random amount of time before restarting the process if no CTS message received.
5.Transmits the data.
6.Acknowledges all transmissions. If a wireless client does not receive an acknowledgment, it assumes a collision occurred and restarts the process

Passive mode

  • AP openly advertises its service by periodically sending broadcast beacon frames containing the SSID, supported standards, and security settings

Active mode

  • Wireless clients must know the name of the SSID. The wireless client initiates the process by broadcasting a probe request frame on multiple channels.

CAPWAP

CAPWAP

  • CAPWAP is an IEEE standard protocol that enables a WLC to manage multiple APs and WLANs.
  • Based on LWAPP but adds additional security with Datagram Transport Layer Security (DLTS).
  • Encapsulates and forwards WLAN client traffic between an AP and a WLC over tunnels using UDP ports 5246 and 5247.
  • Operates over both IPv4 and IPv6. IPv4 uses IP protocol 17 and IPv6 uses IP protocol 136.

DTLS Encryption

  • DTLS provides security between the AP and the WLC.
  • It is enabled by default to secure the CAPWAP control channel and encrypt all management and control traffic between AP and WLC.
  • Data encryption is disabled by default and requires a DTLS license to be installed on the WLC before it can be enabled on the AP

Flex Connect APs

FlexConnect enables the configuration and control of Aps over a WAN link.
There are two modes of option for the FlexConnect AP:
Connected mode – The WLC is reachable. The FlexConnect AP has CAPWAP connectivity with the WLC through the CAPWAP tunnel. The WLC performs all CAPWAP functions.
Standalone mode – The WLC is unreachable. The FlexConnect AP has lost CAPWAP connectivity with the WLC. The FlexConnect AP can assume some of the WLC functions such as switching client data traffic locally and performing client authentication locally.

Channel Selection of 2.4 Ghz

A best practice for 802.11b/g/n WLANs requiring multiple APs is to use non-overlapping channels such as 1, 6, and 11.

Channel Selection of 5 Ghz

Non-overlapping channels are 36, 48, and 60

WPA 3 (802.11Ax) wifi6

Because WPA2 (802.11AC)is no longer considered secure, WPA3 is recommended when available. WPA3 Includes four features:

  • WPA3 – Personal : prevent against brute force attacks by using Simultaneous Authentication of Equals (SAE).
  • WPA3 – Enterprise : Uses 802.1X/EAP authentication. However, it requires the use of a 192-bit cryptographic suite and eliminates the mixing of security protocols for previous 802.11 standards.
  • Open Networks : Does not use any authentication. However, uses Opportunistic Wireless Encryption (OWE) to encrypt all wireless traffic

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Wireless Quiz

This quiz to test Your understanding of Wireless Concept if you didn’t get the pass score I highly recommend to read the article or leave your comment on the post or ask me on live chat ! Do Your best To Be IT Professional

Kindly Fill Your Information Before Taking The quiz

1 / 9

When designing an extended service set (ESS) wireless network, which of the following represents a design best practice?

2 / 9

ESS is a collection of multiple BSS:

3 / 9

Which wireless encryption protocol uses AES as the encryption algorithm?

4 / 9

Which of these standards is called as WiFi 6?

5 / 9

Which wireless standard runs at 54 Mbps?

6 / 9

Which AP solution would you use if you wanted to ensure that the AP could still serve clients when communication to the WLC has failed?

7 / 9

What is SSID (Service Set Identifier) in a Wireless Network?

8 / 9

Which ones of below list are valid Wireless LAN standards?

9 / 9

What type of APs are managed by the WLC?

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