In daily work, we often encounter scenarios where we need to transfer documents between computers. If there is no network device such as router in the scenario, computers cannot be connected to each other through wired LAN, and there is no storage tool such as USB flash drive, how should we achieve the transfer of document information between computers? We can set up an AD-Hoc wireless network through a wireless network card to easily achieve the fast transfer of document information.

What is Ad-Hoc network?

AD-Hoc is also known as wireless mobile self-organizing network. The principle is that one computer host in the network establishes a point-to-point connection, which is equivalent to a virtual AP, and other computers can interconnect directly through this point-to-point connection, eventually realizing the function of simple network file sharing.

Ad-Hoc structure is a peer-to-peer network structure built by eliminating the need for a wireless intermediary device, AP. As long as a wireless network card is installed, computers can be connected to each other wirelessly. Mobile self-assembly network is a build-as-you-go network, a collection of mobile nodes that can form a network without any pre-deployed fixed network facilities. Nodes are always on the move and can join or leave the network at any time. The nodes in the network can act as both hosts for communication and represent routers. A mobile self-organizing network can exist as an independent network or can be connected to the Internet through a gateway.

Characteristics of Ad-Hoc network

Compared with ordinary mobile and fixed networks, AD-Hoc network has the following characteristics:

1. Centerless

Ad-Hoc networks do not have a strict control center. All nodes have equal status, i.e., it is a peer-to-peer network. Nodes can join and leave the network at any time. The failure of any node does not affect the operation of the whole network and is highly resistant to destruction.

2. Self-organization

The deployment or unfolding of the network does not need to depend on any pre-defined network facilities. Nodes coordinate their behavior through hierarchical protocols and distributed algorithms, and nodes can quickly and automatically form an independent network once they are powered on.

3. Multi-hop routing

When a node wants to communicate with nodes outside its coverage area, multi-hop forwarding of intermediate nodes is required. Unlike multi-hop in fixed networks, multi-hop routing in Ad-Hoc networks is done by ordinary network nodes rather than by dedicated routing devices (e.g., routers).

4. Dynamic Topology

Ad-Hoc network is a dynamic network. Network nodes can move anywhere and can be turned on and off at any time, which can cause the topology of the network to change at any time. These features make Ad-Hoc networks significantly different from ordinary cellular mobile communication networks and fixed communication networks in terms of architecture, network organization, protocol design, etc.

How to configure a Ad-Hoc network?

Ad-Hoc network is mainly used for temporary interconnection of two computers, there is no wired infrastructure to support Ad-Hoc network, there is no wireless AP in the network, the nodes in the network are made up of mobile hosts. No matter desktop or laptop, as long as there are two or more computers equipped with wireless LAN cards, you can connect to a wireless LAN anytime and anywhere with a simple setup. This article introduces how to set up an Ad-Hoc network using a TP-LINK wireless card as an example.

1. Setting up Ad-Hoc Network

1.1. Install TP-LINK wireless card driver: After plugging the TP-LINK wireless card into the computer, install the driver and client program.

1.2. Configure the IP address for the wireless card: Since there is no DHCP server under the Ad-Hoc network, you need to configure the IP address for the wireless card manually. The method of manually configuring the IP address may be different for different operating systems.

1.3. Set up Ad-Hoc network: After the installation of NIC driver and client program is completed, open the client application and click “Profile >> Add”. In the pop-up dialog box, customize the configuration file name, set the network name, select “Point-to-Point” as the network type, select “WEP” as the security mode (Ad-Hoc network only supports WEP encryption), and enter the password in the security key. After adding, select the profile in the configuration file and click “Connect”. The system prompts to activate the profile, click “Confirm”. After activating the profile, you can view the relevant parameters and information in “Status”. At this point, the setup in Ad-Hoc network is completed.

Note: The length of the passwords corresponding to different key formats does not depend, as follows.

ASCII_64, where the security key can only be set with a 5-bit ASCII code (arbitrary characters).

ASCII_128, where the security key can only be set to 13-bit ASCII code (arbitrary characters).

Hex_64, the security key can only be entered in 10-bit hexadecimal (0-9, A-F) characters.

Hex_128, the security key can only be entered in 26 hexadecimal (0-9, A-F) characters.

Ad-Hoc network only supports WEP encryption, and the wireless rate can only match up to 54M.

2. Connecting to the Ad-Hoc network

After the Ad-Hoc network is set up, the wireless terminal can connect to the Ad-Hoc network for mutual access.

Double-click the wireless network connection icon in the lower-right corner of the computer, find the Ad-Hoc signal in the pop-up dialog box, and click Connect. Enter the wireless key. After a few moments, the wireless connection is successful. After manually configuring the IP address of the computer to be in the same network segment as the front-end TP-LINK wireless card, you can realize LAN access.

3. Frequently Asked Questions When configuring a Ad-Hoc network

  • How to determine whether the Ad-Hoc network is successfully set up?

After setting up according to the above document, open the command prompt on any computer and use the Ping command to test. If you can ping each other, it means the Ad-Hoc network is successfully set up.

  • What if the Ad-Hoc network is successfully set up but I can’t access each other on the LAN?

If two terminals can ping through each other but cannot access each other, please check whether the firewall is turned on on the computer, and it is recommended to test again after turning off the firewall. If one of the terminals is a mobile terminal (such as cell phone, pad, etc.), you need to borrow third-party software to realize sharing resources.

  • Can a wireless network card realize setting up an Ad-Hoc network while connecting to a wireless signal?

The point-to-point network (Ad-Hoc) and basic mode of wireless LAN card can only be set up one of them. Of the two applications, the application set up later takes effect. For example, if Ad-Hoc network is set first, and then the wireless card goes to connect other wireless signals, the Ad-Hoc network will not take effect.

  • How to disconnect the Ad-Hoc network?

There are two ways to disconnect the Ad-Hoc network.

1. Disconnect from TP-LINK wireless card

Open the client application of the wireless card and delete the configuration file of the Ad-Hoc network.

2. Disconnecting from other point-to-point terminals

Disconnect the Ad-Hoc signal on other point-to-point terminals, at which point the Ad-Hoc network is disconnected, but still exists.

Application areas of AD-Hoc network

Due to the special characteristics of Ad-Hoc network, its application areas are significantly different from those of ordinary communication networks. It is suitable for applications where it is impossible or inconvenient to lay network facilities in advance, or where it is necessary to quickly and automatically set up a network. Its applications are mainly in the following categories:

1. Military applications

Military applications are the main application area of Ad-Hoc network technology. It is the technology of choice for digital personnel battlefield communications because of its unique characteristics of no need to set up network facilities, rapid deployment, and high resistance to destruction. Ad-Hoc network technology has become the core technology of the U.S. Army’s tactical Internet. Ad-Hoc network technology is used in major communications equipment such as the U.S. Army’s recent digital radios and wireless Internet controllers.

2. Sensor Networks

Sensor networks are another major application area of Ad-Hoc network technology. For many applications sensor networks can only use wireless communication technology. Considering the size and energy saving, the transmitting power of sensors cannot be very high. The use of Ad-Hoc networks for multi-hop communication is a very practical solution. Sensors scattered in various locations form an Ad-Hoc network, which enables communication between sensors and with the control center. This has a very promising application in areas such as explosive residue detection.

3. Emergency Applications

After an earthquake, flood, strong tropical storm or other disasters, fixed communication network facilities (such as wired communication networks, cellular mobile communication networks such as base stations, satellite communication earth stations and microwave relay stations, etc.) may be completely destroyed or unable to work properly, and for disaster relief, Ad-Hoc networks, which do not rely on any fixed network facilities and can Ad-Hoc network is a self-organizing network technology that does not depend on any fixed network facilities and can be deployed quickly. Similarly, in remote or isolated field areas, which also cannot rely on fixed or preset network facilities for communication, Ad-Hoc network technology is the best choice for communication in these situations due to its independent networking capability and self-organization feature.

4. Personal Communication

Personal Area Network is another application area of Ad-Hoc network technology. It can be used not only for communication between personal electronic communication devices such as PDA, cell phone and laptop, but also for multi-hop communication between personal LANs. A typical example is the Scatternet in Bluetooth technology.

5. Other

Ad-Hoc network can also be combined with cellular mobile communication system to use the multi-hop forwarding capability of mobile stations to expand the coverage of cellular mobile communication system, equalize the services of adjacent cells, improve the data rate at the cell edge, etc. In practical application, Ad-Hoc network can not only form a separate network to realize local communication, but it can also be used as an end subnet to access other fixed or mobile communication networks through access points to communicate with hosts outside Ad-Hoc network. Therefore, Ad-Hoc network can also be used as one of the wireless access means for various communication networks.