Dynamic DNS in Wireless CCTV Systems (For Beginners)

Wireless internet CCTV, also known as IP CCTV, communicates through your broadband line and onwards to the internet.  This can cause problems if your home broadband has a dynamic IP address, because when you want to connect to your cameras from outside, you won’t know what that address is.  This article shows you how to overcome the problem by using Dynamic DNS.

Most home ADSL packages still give you a dynamic or changing IP address, which is simply the address of your home’s network on the internet.  These addresses are allocated from a pool of available addresses and allow the internet provider to have fewer addresses than customers, saving money. 

This used to work well because early broadband modems “dialled” a connection when the attached computer requested it, rather like the old dial-up modems.  Nowadays, though, modern wireless modem/routers tend to remain connected permanently, so we are reaching the point where the internet provider is having to allow one IP address per customer, and may as well allocate a static or unchanging one.  However, as of today most people have dynamic addresses and this is an obstacle to contacting your wireless internet camera from the outside world, as I will explain in the next section.

Just as your broadband line has an IP address, so your camera has its own address or port.  For example, if your home IP address is 91.103.218.59 and the camera’s port is 8765, assuming your router is set up with port forwarding (outside the scope of this article) you can contact your camera by typing “http:// 91.103.218.59:8765” into a browser window.  This may work today, but by tomorrow that  91.103.218.59 IP address could have been allocated to someone else, and you will not find your camera on the end of it any more.  This is where Dynamic DNS or just “DDNS” comes in.

DDNS allows you to contact your wireless internet CCTV camera using an address that never changes, even when your broadband’s IP address changes.  It requires two things in order to work: a DDNS service provider and a router or camera that offers DDNS support.

Most modern wireless routers offer DDNS support, but few internet CCTV cameras do.  As long as either the camera or the router offers this feature, all is well.  First, you visit the website of the DDNS service provider and sign up for an account.  The most popular provider is dyndns.com and it’s free.  You choose your own unique internet address such as “mywirelesscamera.dyndns.org” and you will also have a user name and password.  (Incidentally, the purpose of this service is simply to make that link between your IP address, whatever it happens to be at the time, and a fixed address or domain name.)  Having registered a DDNS account, next you log into your router’s administration pages and find the DDNS section.

Here you simply key in the DDNS provider name, your account details and the address that you chose.  Now, whenever your broadband provider changes your home IP address, your router will tell dyndns.com, and this means you can always contact your camera from wherever you happen to be, by keying the same unchanging address into a browser window, in our example: “http://mywirelesscamera.dyndns.org:8765”.

Cable, DSL, 3G or Satellite Broadband?

If you are looking at wireless internet CCTV for the first time, you may also be faced with the decision of which type of broadband package to go for: DSL, cable, 3G or satellite? This article aims to help you choose.

If you have decided that you want to see your property from wherever you happen to be, by using CCTV over the internet, you may also be faced with trying to choose a broadband package if you don’t already have one. There are so many types of broadband on the market that it is a daunting task, but I am here to give you some information that should make this task easier.

Here are the main types of broadband available to the domestic customer:

1. DSL Broadband. (The most common form is ADSL.) This is broadband via your existing phone line.
2. Cable Broadband. This uses the line provided by a cable company.
3. 3G/Mobile Broadband. The connection is made through the mobile phone network.
4. Satellite Broadband. This comes through a satellite dish.

Items three and four are really problematic and not recommended for hosting wireless CCTV cameras. Without going too far into the technical details, these types of broadband often block the ports (the specific addresses) through which you connect to the camera from the internet. If you have no choice but to use one of these two options, be prepared for the fact that your wireless CCTV camera may not be viewable from the internet even after a long process of trial and error, reading forums and spending time on the phone to a helpdesk. For this reason alone, this article is going to focus on comparison between the most popular two types of broadband: cable and DSL.

Broadband speeds and packages are changing all the time, but companies always use the download speed as one of the headline selling points. This is unhelpful when it comes to wireless internet CCTV, because the cameras use mostly upload rather than download capacity, as almost all of a camera’s data traffic is made up of images sent up the line. So, when considering broadband for internet CCTV cameras, you need to dig deeply into the broadband provider’s website until you find the upload speed, and believe me, you will need to dig deeply because the upload speed is usually pitifully unimpressive. In home packages and most small business packages, it is often 10 or even 20 times slower than the download speed. In the next section we’re going to look at some of the numbers.

Cable broadband can in theory have a download speed of up to 30Mbps, but most packages offer something between 1 Mbps and 6 Mbps. On the upload side, cable offers between 128Kbps and 1Mbps. DSL comes in at between 2Mbps and 24Mbps on the download side and between 128Kbps and 1Mbps on the upload. Looking at the upload side of the equation which is what we’re interested in for internet CCTV, you can see that there is no difference between the ranges for cable and DSL. However, there will be a big difference in performance from a package with 128Kbps upload speed compared to one offering 1Mbps. Let’s say your camera produces a series of images that, when viewed one after another, appear as video.

If each of these images is 15Kb in size, the broadband upload speed has the following effect on the number of frames per second or fps:
Upload speed 128Kbps: 1fps
Upload speed 1Mbps: 8fps

This really makes a big difference. Viewing streaming images from an internet CCTV camera at 8fps gives a real approximation of movement, whereas 1fps certainly does not. So, whether you choose cable or DSL, be careful to get the best upload speed that you can.

Pricing for cable and DSL packages is very competitive these days, and as with upload speed, there is no clear winner. Suppliers are bundling in all sorts of other services that makes a direct comparison more complicated. All I can say is that it is definitely worth spending an hour on the internet looking at current offers and taking note of reviews, especially bearing in mind that you may have to sign up for as long as 18 months.

Overall then, for internet CCTV I would rule out 3G broadband and satellite broadband unless you have no other choice, and even then it is a gamble. As for the remaining options, either cable or satellite will work well with wireless CCTV cameras, but please get the very fastest upload speed that you can afford.