How IP Cameras Work

made easy to understand

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General

• IP cameras are in a way mini computers. IP cameras have their own local IP addresses just like any other computer and connect to routers in order to be found externally.


Local Connection

Local IP addresses such as 192.168.1.3 as an example are only used within a local network by the routers to recognise the computers in the network.
• When we want to connect to an IP camera locally (within our home/local network) we use the local IP address and a port number. The router, uses the port number to establish a connection with the desired computer or IP camera and does exactly that by using the local IP address.
• At this point we can only connect with an IP camera within a local network.


Remote Connection

• As local IP addresses are only visible and relevant within our home network, we need an additional setup so we can access our IP cameras remotely (from outside our home/local network).
• Using our IP address assigned by our ISP (internet service provider), we can establish a connection over the internet with our home router, and from here we use a port number for the router to know that we are intending to communicate with the IP camera and further the router uses the local IP address to send and receive data/information to and from the IP camera.
• The IP addresses assigned by the ISP can be either static or dynamic.
• A static IP address is a permanent address which doesn't change, so it is easy for us to use this address to connect to our IP camera. For security reasons and not only, most of us have a dynamic IP address.
• A dynamic IP address means that it changes all the time, may be after a few hours or days or weeks which makes it hard for us to connect to our home router externally as we need to know our home IP address. This is where a DDNS (dynamic DNS) service comes into play.


DDNS

DDNS is a service which stays in permanent connection with a router and checks the current IP address. When the IP address changes, the DDNS service knows about it and updates a URL address given by the DDNS service to represent the router's new IP address.
• Is a DDNS account strictly necessary? Short answer: NO. As long as we can find out what our current IP address is, we don't need a DDNS account. But if we want to connect to our IP camera remotely and we don't know what our home IP address is, becomes difficult to find out. It requires us to get in contact with someone at home to manually check the IP address and report it back to us.
• This is where the DDNS account comes in handy as it does the work for us. Most of IP cameras come with a free DDNS account but it is not guarranteed that will be available forever.
• There are some free and some paid DDNS services. The most popular paid service is DYNDNS.COM and a free or paid service I've found and use is NOIP.COM


Port Forwarding

Port forwarding is a process through which we tell the router and modem how to access our IP camera when we are away (not in within our home/local network).
• We do this by telling the router and modem that whenever we connect to the router from outside of our local/home network and use a specific port number, to establish the connection with our IP camera based on its local IP address.


Live Stream

• When we watch a live stream from an IP camera what it actually happens is the IP camera sends us a series of images/frames and based on the internet speed available the sequence of images may be smoother or choppier.
• The higher quality image and frame rate the stream is, the larger amount of data is being transfered/downloaded.
• A good advice is to monitor the data usage when on a 3G/4G device, unless an unlimited plan is in place.
ipCamControl-Lite FREE iPhone app » works over WIFI or 3G/4G and gives user the opportunity to change the image stream size between 320/240 and 640/480 and also the option to adjust the frame rate FPS (frames per second) where the IP camera firmware allows it.

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