A Cyber-network was the network that linked every Cyberman to one another. It contained their database and was used transfer files wirelessly. (TV: Rise of the Cybermen) It could also receive information from infostamps, giving Cybermen a means of exchanging information when their wireless systems were inactive. (TV: The Next Doctor)
To destroy the reviving Cybermen whose Cyber-ship crashed in Klimtenburg on Earth centuries before the 19th century, the Eleventh Doctor cut off a partially-converted Victor Ernhardt from the Cyber-network. Victor's Cyber-body was then charged with excess power from a lightning stike so when he was reconnected to the network, the other Cybermen overloaded and died. (PROSE: Plague of the Cybermen)
Marcus Bertrand, assimilated into the Borg Collective, set all Cyber-ships present in the Federation universe to self-destruct over the Cyber-web after the defeat of the Cyber-Controller. (COMIC: Assimilation²)
In the 2000s, the CyberMondans of the Forth Generation had a cyber-network. (AUDIO: The Forth Generation)
During the Cyber Wars of the 250th Millennium, the Cybermen of the Cyber Legions were connected via the Cyberiad, a particularly advanced Cyber-network, (PROSE: Ghost in the Machine, The Mondas Touch, TV: Nightmare in Silver) and, in one alternate timeline, dominated all of time and space. (COMIC: Supremacy of the Cybermen) A race of Cybermen from an alternate universe, who sought to upgrade the entire multiverse, were connected via the Cyber-Mainframe, a Cyber-network that connected billions of Cybermen to each other from across dimensions; the Mainframe also allowed the electricity generated from the worlds the Cybermen conquered and turned into batteries to power each individual Cyberman connected to the Cyber-Mainframe. (AUDIO: Code Silver, Master of Worlds)