Wireless Networking, Wireless Bridges, Wireless How-Tos and more

This is an excerpt from my blog post at securityinfowatch. For the entire post please click here.

Wireless Mesh seems to still be misunderstood so I though I would put down a couple of pointers explaining how it works at a high level and focusing on throughput of course, we are talking about video here…  Wireless mesh networks require a good amount of planning and unfortunately are not as easy to deploy properly as most vendors would like you to think, but can be useful for specific applications.  Here is a top down diagram of the different parts of a wireless mesh network.

A wireless mesh network normally spans a large area of land and therefore requires a distributed architecture in order to make it work.  The diagram above attempts to break down the typical components of a wireless mesh network.  You may notice that I used Motorola Canopy Visio stencils to make this diagram but I only did that because those were the only stencils I had and Moto has a nice representation on their website that helped me put this together.  I am not endorsing a specific manufacturer in this blog and recommend that you look through the many manufacturers and find the one that is right for your application.

For the entire post please click here…

It has been brought to my attention that I forgot to mention how to fix the problem of weak client side transmission, which I discussed back on August 18th. So I figured I would quickly fill in that void.

There are several ways to increase the range of your wireless client and each has its own benefits and drawbacks. Now, while you read this entry please remember that, like a standard wireless access point or bridge, there are always two parts to a wireless client, the “radio” and the “antenna“. The radio is the device creating the RF signal and the antenna amplifies that signal.

So that being said I am sure you can guess that the first way to increase the range of yourwireless client is…Add an antenna!

1) Add an antenna to your client device. In mobile applications you would want anomnidirectional antenna (signal is radiated in a 360 degree pattern) and for fixed environment you would be better served by a directional panel antenna or grid antenna (signal is more focused in a certain direction). Of course you need to have a client device (PC card or laptop card) that has an external antenna connector built in. The major issue is that most (99%) of laptops have integrated wireless cards and antennas that can not be upgraded in which case you might better be served by number 2 below.

2) The next step is to add a wireless card into your laptop or desktop that has the necessary external antenna connector and then add a high gain external antenna to really boost the signal. This is a pretty easy way to increase wireless transmission and is great for laptops however not so great for desktops. If you want to use this method to increase your wireless signal on your desktop you will normally be required to run a good amount of coaxial cable from the PC up and out to the external antenna. This is definitely the method of choice for laptops but I find it a little cumbersome for desktop machines. Below you can find a picture of cards with external antenna connectors.
The one of the left is made by Ubiquiti Networks and goes in the PCMCIA card slot on the side of your laptop. The one on the right is a PCI card for your PC. You can remove the rubber duck antenna that comes with the card and install coax cable that runs to the antenna you installed on your roof.

3) The third option is great for fixed environments like homes, RVs, boats, etc. Purchase anexternal wireless client that sits on the roof of whatever structure you are in. This client can be an all in one device with both the radio and the antenna built in to one unit or you can purchase one with an external connector for higher gain antennas. Here is what they look like…
Here is how you would use them…

Option 1: Install the external wireless client on your roof, point it at your ISP, run an Ethernet cable from the client to the power over Ethernet injector and then plug it in directly to you PC.

Option 2: Install the wireless client just like in option one but instead of plugging directly into your PC plug it into a wireless router! This will allow you to rebroadcast the signal from outside wireless INSIDE your house, giving you the best of both worlds!

Hope this helps!

1. Decide the number of cameras you need for your installation
2. Choose the codec or combination of codecs, frame rate, resolution and the estimated recording time for each camera.
   • Codecs: MJPEG, MPEG4, MXPEG, H.264
   • Frame rate: Up to 30 fps. From experience you will see that 4-6 frames per second will be sufficient in most security applications.
   • Resolution: CIF (320×280), 4CIF (640×480), 1.3MP (1280×1024), 2MP (1600×1200), 3.1MP (2048×1536), 5MP (2560×1920)
3. Use calculators to estimate amount of storage and server requirements.
   • MJPEG Storage Calculator
   • MPEG4 Storage Calculator
   • Server estimator
   • Lens Calculator
4. Order your server and configure the server according to calculated specifications. Below you will find some best practices. Please refer to the image below while reading this section.
   • Live database should be written to fast reliable SCSI or SAS hard drives.
   • Create a RAID1 logical drive using 2 physical SCSI or SAS disks. Then…
     • Carve out a 20GB or so partition for the operating system (C: drive) and then partition the rest for the live database (D: drive).
     • Depending on the number of cameras in your system you may not have enough capacity for the entire live database on the D: drive so extra disks will be required. These extra disks should be configured as individual RAID0 virtual disks in your RAID controller.
       • The RAID0 is important because it speeds up the write time which is critical in IP video where data is constantly being written to the media.



5. Setup physical archive storage. Your archive storage should be protected from loss so a RAID5 configuration is a good choice. In a small system you can use internal disks but in larger systems you will need either an external disk array, a NAS or a SAN. (see the figure above)
6. Install Milestone on C: drive
7. Through the Admin, install the DLKs provided to you by your Milestone Certified Partnerand add all the cameras to XProtect.
8. Set up camera parameters. With the recording server stopped go through each and every cameras configuration and recording, event and motion attributes. Be sure to set each camera’s live database directory to the appropriate disk. Please refer to step 4 and the image below.



9. Set up camera archive parameters. Go through and set up each cameras archive schedule and directory.



10. In the Image Server Administrator, set up users (basic or active directory) and give them access to view specific cameras on the Milestone XProtect system.

That’s it!