How is urban video surveillance organized?

Question

Computer networks

How in practice the connection of urban surveillance cameras is arranged.
Locally, on the territory of a house, office, enterprise, it is clear: Internet, wi-fi, static IP or SIM card and p2p - there are no problems here.
And what about within the city, over long distances? For example, the length of the city is 50-100 km.
How, say, 50-70 cameras scattered throughout the city, get access to one video recording server?

Answer 1

In small urban projects (100-200 cameras) they drive through the Internet and local providers. Software - usually premium versions of any ISS Securos or ITV Intellect.
Large projects are built on a fundamentally different principle. For example, "Safe City Moscow" now has 175,000 cameras. A list of equipment is formed, the quality and functionality of which suits and is supported by the API for communicating with the ECHD, regulations are made for video acceptance (bitrate, frame rate, camera coordinates and azimuth). ETsHD (Unified Data Storage Center) is being built - a storage room for 16 Pb.
Further, the provider (rtk, megaphone, akado) participate in tenders for the "delivery of video images". Their subcontractors mount cameras, providers transmit video streams to ECHD through their network. There are 2 types of integration, 1 - cameras give RTSP, storage in the ECHD, type 2 - storage on the DVR at the facility itself, the ECHD, if necessary, can pick up RTSP broadcasts and send archive export requests to the DVR.
The user part of the system consists of vpn clients up to the ECHD and a personal account.

Answer 2

How, say, 50-70 cameras scattered throughout the city, get access to one video recording server?

In short: nothing unusual - a routine at the level of "make a video at the enterprise."
Lines + video signal processing software with a bunch of their whistles + servers.