CMCC Learning

one。 DCN Data Communication Network data communication network

Transmit all kinds of management information of provincial network management centers to DGT.

two。 GSM Global System for Mobile communications Global system for Mobile Communications

At present, the most widely used mobile phone standard is being used in more than 200 countries and regions around the world. It is because of its widespread use that it is possible to roam in different parts of the world. This is also the origin of the name "GSM", an important business brand of Mobile.

Compared with analog communication technology, GSM is the second generation (2G) communication technology, which adopts time division multiple access (TDMA) technology and the transmission rate is 9.6Kbps.

Frequency band:

900MHZ

The effective bandwidth is 25MHZ (why), 124 carrier frequencies (what), and each carrier frequency has 8 channels.

1800MHZ

The effective bandwidth is 75MHz and 374 carrier frequencies, each with 8 channels.

three。 GPRS General Packet Radio Service General packet Radio Service

A mobile data service available to GSM mobile phone users, a network supporting high-speed packet data is added to the GSM network, and the transmission rate can be increased to 56 or even 114Kbps. GPRS is a technology between 2G and 3G, also known as 2.5G.

four。 CMNET & CMWAP

five。 Multiple access mode

six。 Shannon's theorem

SCG

EMOS

WVS scanner

Nessus scanner

Whether DNS is open DNS

Tamper-proof system for Web pages: principle and composition

URPF:Unicast Reverse Path Forwarding

Flow reinjection technology