extensive, large, vast, wide, widespread
an extensive network of underground tunnels

complex, elaborate, intricate
dense
global, local, national, nationwide, regional, worldwide
neural
the structure of the brain's neural networks

bus (esp. BrE), motorway (in the UK), rail, railroad (AmE), railway (BrE), road, train
distribution
integrated

build up, construct, create, develop, establish, set up
They are establishing a network of pumps and pipelines to move the oil.

launch
form
The new rail services will form a network connecting the capital and major cities.

join
Once a supplier joins the network, its shipping systems are integrated with the others.

use
operate, run
maintain, manage
expand
destroy, dismantle
We are dismantling the financial networks that have funded terrorism.

infrastructure

in a/the network
one of the depots in the company's network

through a/the network
Drinking water is brought to the town through a network of underground pipes.

via a/the network
The newspapers are sent out via a national distribution network.

network of
a network of threads

strong
a strong network of friends

supportive
informal
grass-roots
social
old boy (BrE,informal)
support
terror, terrorist
We must fight terrorist networks and all those who support them.

build up, create, form

in a/the network
Members are all linked together in a network.

network of
a network of friends

computer
cellphone (esp. AmE), communications, mobile, phone, telephone
high-speed
corporate
peer-to-peer
Wi-Fi, wireless
laptops connected to wireless networks

wired
file-sharing, local area (abbreviated to LAN), wide area (abbreviated to WAN)
broadband, VoIP

install, set up
maintain, manage, operate, run
software to help you manage your network
They were unable to run the telephone network economically.

upgrade
access
secure
Administrators can secure the network by segmenting it into zones.

administrator, controller, engineer, operator
access, address, connection, device, protocol, provider, security, server, traffic

across a/the network
Users can access data across a network.

on a/the network
All computer users are connected on a network.

over a/the network
The files are accessible over a network.

broadcast, news, radio, television
cable, digital, satellite

news, newscast (esp. AmE), show (esp. AmE), television
anchor (esp. AmE)

on a/the network
The show was first aired on the cable network Showtime.