Remote Access Control Technology Research

No stranger to remote access technology. To put it bluntly, it is P2P Technology (what I mean here ).

For example, QQ or MSN. The most representative is Skype, which brings P2P and DHT networks to the extreme.

 

Remote access control is used to remotely operate the desktop and file system of the other party. You can remotely enable the camera and operate sound card recording. This is a required technology for remote teaching and technical support.

 

The popular remote control software (non-Trojan Horse) on the market has a foreign team viewer, such as netman in China. Early software such as glaciers. In fact, this type of technology can be used for Trojans, remote technical support for users, video conferences, etc. The so-called "benevolent sees Benevolence" and "Obscenity.

 

VNC is an excellent open-source screen control project. I recently studied it at the invitation of a friend. VNC is characterized by the area change screen capture technology. It is highly efficient and fast to drive screen capture, compared with QQ remote assistance, it was found that the same bandwidth is much better than QQ Remote Assistance.

 

There is a small software for testing, www.gnetcom.com. If you are interested, you can check it out.

 

Note the following key technologies:

 

1) For NAT firewall traversal, the common method is the so-called holes, as well as the HTTP tunnel, UPnP. trun stun, which can be implemented by the server. In addition, you can modify the HTTP tunnel for firewall traversal. However, deploying trun servers is expensive.

2) for large concurrency, this type of system certainly includes several basic types of servers. The trun/stun server mentioned earlier must also include the Presence Server, that is, the login server. Responsible for user logon and online status. For the background of large-scale im, the common practice is to hash the back-end database tables + cache + distributed servers. The presence servers must be connected through a certain message bus, or you can directly operate on the backend cache. In this way, users can log on to different servers for interaction. The architecture of high concurrency does not care how many users are supported by a single machine (of course, it cannot be too much). TCP can support at least 3 W, UDP... The key lies in service scalability to achieve real-time resizing.

3) real-time transmission of video and audio. Generally, videos can be hh264 codec, and audios can be in gips or other formats. I have purchased gips for piracy on the Internet. I don't know if it is credible. It is said that it can be used for 10 years, the price is more than 1000 yuan. Gips should have the best voice effect. Video and audio must be recorded in real time.

 

4) P2P support, supporting popular P2P live broadcast and DHT networks, which can save a lot of server bandwidth. It is said that the Improved Chord algorithm is better. But I have never tried it.