Commonly Used Terms

The adoption of IP continues to grow worldwide, and in the video surveillance industry it is predicted that implementation of IP video surveillance will grow over 200% from 2010-2012 (IPVideoMarket.info). To keep up with this growing trend, you are going to need to understand some of the most common terms being used in the industry:

IP Camera

An Internet protocol camera, or IP camera, is a type of digital video camera commonly employed for surveillance, and which unlike analog closed circuit television (CCTV) cameras can send and receive data via a computer network and the Internet.

Although most cameras that do this are webcams, the term “IP camera” is usually applied only to those cameras used for surveillance. This type of camera is connected via an Ethernet cable and does not require the Coax cable used with standard analog cameras.

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Internet Protocol (IP)

IP is the principal communications protocol used for relaying datagrams, or packets, across an inter-network using the Internet Protocol Suite. It is responsible for routing packets across network boundaries, and it is the primary protocol that establishes the Internet. In layman’s terms, this is set of rules which tells computers, IP cameras, and anything connected to a network how to talk to each other.

IP Address

An IP address is a unique identifying number for a device on the network. Without an IP address, a network device cannot send or receive data. Just like your postal address tells your mailman where to deliver your mail, the IP address tells the network where to deliver data.

Two types of IP addresses:

1. Local (or private) IP address These are IP addresses on the local network which cannot be accessed from other locations. They do not have to be unique from site to site.
2. External (or public) IP address These are addresses which are accessible from anywhere on the internet. Because there are a limited number of these in existence, one office with many computers may have a single External IP address. These DO have to be unique.

Subnet Mask

In short, this defines how many devices are on a given network and which devices share that network. Having the correct value of subnet mask (usually in a form similar to 255.255.255.0) is critical to effective network connectivity.

Default Gateway

This is the first stop for any network traffic sent from the device onto the network. Similar to how your local post office decides how to pass along any letters you send out, the Default Gateway is the first network device to receive your network data and decide where it should be passed along. Typically all devices on the same local network (LAN) will share the same Default Gateway.

Static vs. Dynamic IP addressing

IP addresses can be assigned to a device in two different ways:

Static IP addresses require an administrator to manually enter an IP address into the device and that value will not change unless manually modified. When entering this information, the administrator will also have to enter additional data points such as the Default Gateway and the Subnet Mask.

Dynamic IP address allow another device on the network (a DHCP server) to assign an IP address (as well as the Subnet Mask and Default Gateway) to a device. When a camera or computer is set to dynamic (sometimes labeled as ‘Automatic IP address assignment’) it will reach out to anyone on the network who can provide it IP address settings. This is normally provided by the router or perhaps by a server in a corporate environment.

It is also important to note that Dynamic IP addresses can change without notice as the router or server providing these IPs accounts for more or less devices on the network. For this reason, security cameras are often recommended to be set to a Static IP address.

LAN

Short for Local Area Network, this is defined as a set of devices or computers who can communicate without sending their data out to the internet. Placing your security cameras and your recording server on the same LAN will help to ensure fast communication between them and avoid lag or delay in video.

Switch

This is a machine which can connect a number of devices to the LAN. The switch can be managed (having its own interface to control configuration) or unmanaged (sometimes called a dumb switch or a hub). These devices can help to direct traffic and keep organization within larger LAN environments.

Router

A router is a device which organizes and arranges communication between networks. Routers will often function as the Default Gateway as well as providing communication between the LAN and the internet.

PoE

Power over Ethernet is a way to provide power to devices such as security cameras via the same Ethernet cable which is transmitting data. This allows us to connect an IP camera to a PoE enabled switch and not have to run any additional wires.