On the basis of CDMA mobile intelligent network, China Unicom has built a unique, large-scale and unified virtual private network-"Intranet". The "network in the network" uses the existing switches to realize the compatibility of different manufacturers' equipment, realize national roaming, and provide the function of reducing dialing. Providing differentiated services for users is a pioneering work of China Unicom and an important achievement of technological innovation of China Unicom in the field of mobile communication.

As a unique service provided by CDMA, "Network in Network" service is most suitable for companies and groups. Once a company or group applies for "in-network" service, internal employees can call each other on CDMA mobile phones, so they can talk to each other by dialing the last four digits or the number of the other party's extension, which reduces a lot of trouble. Another advantage of "net in the net" is that the tariff is cheap. "Net in the net" is cheaper than the current standard. At present, the "net in the net" has achieved nationwide coverage, which means that users belonging to the same "net in the net" can still enjoy low telephone charges even if they roam abroad. At present, China Unicom has several branches in Beijing and other places. , you can handle the "network in the network" business for users.