What are Some Different Types of Resource Centers?

There are different classification methods for networks from different perspectives, and each network name has a special meaning. The combination of several names or names plus parameters can more clearly see the characteristics of the network. Gigabit Ethernet represents a bus-type network with a transmission rate of up to Gigabit. Understanding the classification method and type characteristics of the network is one of the important foundations of familiarity with network technology.

Network Type

We often hear terms such as internet and star networks. What do they mean? How is it classified? The following lists common network types and classification methods and briefly introduces their characteristics.

The common wireless wide area communication networks in China mainly include CDMA, GPRS, CDPD and other network system types.
CDMA (Code Division Multiple Access), also known as code division multiple access, is a technology used in wireless communications. CDMA allows all users to use all frequency bands at the same time, and treats signals sent by other users as noise. There is no need to consider the problem of signal collision. The CDMA network is a network operated by China Unicom, and a more stable CDMA 1X network system has been introduced. CDMA 1X is an upgrade based on the original CDMA, with faster speed and higher capacity.
CDMA 1X can provide users with wider bandwidth. In addition to basic services, it also provides wireless data services. Wireless data services include the following services:
(1) Short message service: such as sending and receiving short messages, call charge inquiry, cell broadcast, ringtone download, LOGO picture download, Ruyi call, etc .;
(2) Wireless Internet services: such as WWW browsing, WAP browsing, sending and receiving E-mail, FTP, mobile QQ, information on demand, etc .;
(3) Mobile positioning services: such as emergency assistance, tracking services, navigation, city maps, location-based content broadcasts, mobile yellow pages, etc .;
(4) Mobile e-commerce business: such as e-banking, e-lottery, e-ticketing, mobile payment, booking services, mobile stock trading, etc .;
(5) Mobile multimedia services: such as video on demand, video phone, interactive games, etc .;
(6) Mobile VPN business, large group users such as banks and foreign companies can also directly use CDMA networks to build their own virtual private networks.
GPRS network standard GPRS is called "General Packet Radio Service" in English, and it means "General Packet Radio Service" in Chinese. It is a set of GSM-based wireless systems developed using the concept of "Packet-Switched" transfer method. The so-called packet exchange is to encapsulate the Date into many independent packets, and then transmit these packets one by one. The form is similar to sending a packet. The advantage of using packet exchange is that it only takes up bandwidth when there is data to be transmitted, and It can be priced based on the amount of data transmitted, which is a reasonable charging method for users, because most time bandwidth of data transmission such as the Internet is interlaced.

Compared with the circuit-switched data transmission method of the original GSM dial-up method, GPRS is a packet-switched technology that has the advantages of "real-time online", "charge-by-amount", "quick login", "high-speed transmission", and "free switching". The theoretical maximum transmission speed of GPRS is 171.2kbps. In actual use, the speed is affected by the external environment, especially it has a large correlation with the load of nearby base stations. Generally, the transmission rate is 30-70kpbs, which can meet most M2M and SCADA system data transmission. GPRS network is widely used in industrial remote measurement and control and the Internet of Things.

CDPD network format CDPD is an abbreviation of Cellular digital packet data, that is, a cellular digital packet data exchange network. It is a wireless mobile data communication technology based on packet data communication technology and using a cellular digital mobile communication network. For true wireless internet.
CDPD network is a mobile wireless data communication network based on digital packet data technology and cellular mobile communication as the networking mode. To use CDPD, you only need to connect a dedicated wireless modem to the portable computer. Even if you are sitting in a car with a speed of 100 kilometers per hour, it will not affect the Internet. CDPD has a dedicated wireless data network, and the signal is not susceptible to interference and can be accessed on any website. Compared with other wireless Internet access methods, the CDPD network can reach 19.2 kilobits per second. CDPD also has many features in use: easy installation, users do not need to apply for a telephone line or other lines; communication connection response is fast, such as in the business card, using MODEM connection time is 20-45 seconds, and CDPD only 1 second; The terminal system is divided into two types: mobile and fixed, which can realize local and remote roaming.
CDPD can support mobile Internet access, remote telemetry, vehicle scheduling, bank withdrawals, wireless stock trading, field services, commercial POS systems, and more.