What are the classifications of WLAN _Shang pin China focuses on high quality website construction - 上海1314龙凤鲜花坊_上海419贵族宝贝

WLAN can be divided into two categories: one is with fixed infrastructure, the other is without fixed infrastructure.

1. Wireless LAN with fixed infrastructure

802.11 standard stipulates that the minimum component of WLAN is the Basic Service Set (BBS). A basic service set includes a base station and several mobile stations. All mobile stations can communicate directly within the BSS. To communicate with mobile stations other than the BSS, you must forward services through the base station of the BSS. The base station can also be called an Access Point (AP).
As shown in Figure 5-12, a basic service set can be isolated or connected to a distribution system (DS) through an access point AP, and then connected to another basic service set to form an extended service set (ESS). In an ESS, when Mobile Station A roams from one basic service set to another, Communication with another mobile station B can still be maintained.

The extended service set ESS can also provide wireless users with connections to other networks (non 802.11 WLAN) through a device called portal, such as connecting to the 802.13 LAN or the Internet, as shown in Figure 5-13.

2. Wireless LAN without fixed infrastructure

Wireless LAN without fixed infrastructure, namely Ad hoc Network. Ad hoc network does not have access point AP in the above basic service set, but is a temporary network composed of some mobile stations
Among them, all mobile stations have equal status, and both routing and data forwarding Website production Function.

Formation of mobile ad hoc network: within a certain range, several mobile devices connect and communicate with each other through the ad hoc network routing protocol, as shown in Figure 5-14

1) Problems to be solved in mobile ad hoc networks

(1) Routing protocol: Since each mobile station in the ad hoc network must participate in the route discovery and maintenance of other mobile stations in the network, and the network topology composed of mobile stations may change rapidly with time, some routing protocols that are effective in fixed networks are no longer applicable to mobile ad hoc networks.

(2) Multicast: This kind of multicast is more complex than fixed node network multicast, and requires a multicast protocol with good real-time performance and high efficiency.

(3) Security issues.

2) Application prospect of mobile ad hoc network

In the military field, soldiers with mobile stations can use the temporary mobile ad hoc network for communication. This networking mode can also be applied to the ground vehicle group, tank group, ship group on the sea and aircraft group in the air. When natural disasters occur, it is one of the most effective methods to use mobile ad hoc networks for timely communication during rescue and disaster relief.

3) MANET and Mobile IP are different

Mobile IP technology enables roaming hosts to connect to the Internet in a variety of ways, and roaming hosts can connect directly or through wireless links to another subnet of the fixed network.

The core network function of mobile IP is still based on various routing protocols used in the fixed Internet.

Mobile ad hoc network is an autonomous system that extends mobility to the wireless field. It has its own specific routing protocol and can not be connected to the Internet.

What are the classifications of WLAN

Date：2015-07-15 Source: Shangpin China Type: website encyclopedia
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