Can anyone tell us about wireless LANs?

The architecture of a wireless LAN is slightly different from that of Ethernet, in that a wireless LAN adds a logical link control (LLC) sublayer to specify the data type.

The specific way to represent the data type is to add a 2-byte Ethernet type field with a fixed prefix aa03000000

The reason for this difference is that Ethernet and Wi-Fi use different standard-defined MAC frame types.

The smallest unit of a wireless LAN is the basic set of services.

Features:

The maximum transmission distance is 100 300 meters.

is a collision domain with a limited number of endpoints.

Created by one endpoint and joined by other endpoints.

Mac Frame Transfer Process:

The source terminal sends data to the destination terminal.

The destination terminal correctly receives the data and replies to the reply frame.

Features:

There is a device called an AP.

Endpoints are interconnected via APs.

BSS can be interconnected with other networks via APs.

Mac Frame Transfer Process:

If the source and destination terminals are in the same BSS, the communication between the terminals is confirmed through AP ** and segmented during transmission.

The geographic extent covered by the basic set of services is calledEssential Service Area (BSA).

Features:

A wireless LAN is equivalent to a network segment.

AP implements MAC frames between Ethernet and Wi-Fi**.

AP converts Ethernet MAC frame formats to and from Wi-Fi MAC frame formats.

Mac Frame Transfer Process:

Features:

Mac frame format

Note: The "To DS" bit is set to 1 when the receiver of the MAC frame is an AP, bridge, or other device

From DS" is set to 1 when the sender of the MAC frame is an AP, bridge, etc

BSSID is an abbreviation for Basic Service Set Identification and is known asBasic service set identifier, is a 48-bit number generated by IBSS when it is created, and is generally the MAC address of the AP, which is used to uniquely identify the IBSS

For APs, you need to configure:

For a terminal that needs to be connected to BSS, you need to configure:

During the synchronization process, the terminal needs to complete the following tasks:

The synchronization process is divided into:Passive synchronization processwithActive synchronization process

Passive synchronization process

Active synchronization process

The process by which an AP authenticates an endpoint

Open system identification

Shared key authentication

The endpoint is associated with the AP

Prerequisites: After the synchronization and authentication process is completed, the AP has the resources required for terminal access, such as the capacity of the association table and the number of terminals that can be associated.

Once the association is established, the AP adds the MAC address of the endpoint to the MAC address list, and only endpoints that have a MAC address in the MAC address list of the AP can pass the AP ** data.

Wireless LAN networking.

A Mac frame for a Wi-Fi network.

The process of connecting a terminal to a wireless LAN.

This is a hotspot for other iPhones, and when you pair with him, the phone will automatically connect to the hotspot. No different from normal wifi.

Just a normal phone hotspot.

WLAN is also the old age is the WiFi that we often contact in our lives, but it is not the same as WiFi, in fact, WiFi is a trademark of WLAN (Wireless LAN Alliance), the trademark only guarantees that the goods using the trademark can cooperate with each other, and the standard itself has nothing to do with it. In terms of inclusion, WiFi is a standard for WLAN, and WiFi is included in WLAN, which is a new technology that adopts the WLAN protocol.

For example, in an enterprise network, APs can be placed in offices, conference rooms, meeting rooms, and other places, while ACs can be placed in company computer rooms. Therefore, in large-scale networking, three-layer networking is generally used.