Networking for Video Surveillance: IP addressing

A look at IPv4, subnets and public vs. private IP addressing

  • - (10/8 prefix)
  • - (172.16/12 prefix)
  • - (192.168/16 prefix)

For a device assigned one of the private IP address to be reachable over the Internet, the private address must be translated to a public address. Routers and firewalls use Network Address Translation (NAT/pNAT) to perform the translation.

In many instances, the organization does not have requirement to access cameras directly from the public Internet, so private addressing is ideal for IP video surveillance deployments. In fact, most surveillance management systems stream the camera feed first to a NDVR; viewing of live or archived video feeds are through the NDVR acting as a proxy to the cameras. The NDVR is allocated a public IP address, the cameras can be allocated private IP addresses, and viewing stations on the Internet access video directly from the public IP address of the NDVR.

This article examines how IP cameras communicate over an IP network by using IP addressing to transmit video feeds from cameras to servers. Routers and hosts like cameras and servers use the subnet mask of assigned along with the IP address to decipher which part of the address identifies the network verses the hosts of that network. Private IP addresses are ideal for cameras because in many instances, they need not be accessible directly outside the enterprise network. In next month's article, we will examine how IP video surveillance cameras obtain an IP address and the role of Dynamic Host Configuration Protocol (DHCP).