Point-to-point - When it is necessary to connect two buildings or sites with a high-speed network, a point-to-point data link capable of long distances and high speeds is required. These connections can be wired -- using fiber cabling -- or wireless, using radio waves or an optical link. Point-to-point can be a good option to consider when you're faced with the challenge of trying to create a central security command center when buildings are spread out among a large campus, or are separated in a town and it suburbs.
Some wireless point-to-point links require direct line-of-sight (LOS) between the two points in order to establish a connection. This means there must be a direct, visible path between the transmitting antenna and the receiving antenna to establish a link. This can prove difficult in mountainous terrain or in urban areas where taller buildings may disrupt LOS. There are cost-efficient solutions for point-to-point in the 900 MHz range that can transmit data a few miles with non-line-of-site (NLOS), and up to 40 miles with LOS.
Point-to-multipoint - Point-to-multipoint distributes data from a single source to multiple targets. The typical range is up to 15 miles at data speeds up to 72 Mbps. Point-to-multipoint links can be done with LOS or NLOS technology, depending on the needs of the surrounding area. Deploying a wireless point-to-multipoint system is much more cost efficient than a wired system that can require laying cabling across vast distances.
Mesh networks - In a mesh networking setup, all or most devices on the network are connected directly to each other. If one device can no longer operate, all the rest still communicate with each other; it's the concept of a "self-healing" network. Mesh networks work well when cameras are located at scattered points, but can be very expensive to establish when using wired connections. A wireless network allows these devices to network together without the need for physical cabling.
Security in Wireless Networks
Wireless networks allow for added flexibility in the placement of cameras and other networked devices throughout the system, but they require added security measures. WLANs are not necessarily bound by the walls of the buildings they serve, which open them up to security issues not faced with wired solutions. Due to the nature of wireless communications, everyone with a wireless device within the area covered by the network can potentially access its applications.
To address these concerns, there are a number of different methods for securing wireless networks, including Wireless Equivalent Privacy (WEP), WiFi Protected Access (WPA), and WiFi Protected Access 2 (WPA2), plus a number of proprietary solutions.
WEP - WEP encrypts data transmitted over the WLAN. Once WEP has been established, other typical LAN security mechanisms such as password protection, end-to-end encryption, virtual private networks, and authentication can be put in place to further ensure privacy. WEP adds encryption to the communication and prevents people without the correct key from accessing the network. However, the encryption code in WEP is static, which makes it vulnerable to attacks with inexpensive off-the-shelf software. Therefore it should not be the only method used to secure a wireless network.
WPA - WPA was created as a response to flaws in WEP. WPA works with most wireless network interface cards. With WPA, the access key is changed with every transmitted frame using Temporal Key Integrity Protocol (TKIP). This makes it much more secure, and it is now considered the basic level of security necessary for wireless networks.
WPA2 - For even higher security, WPA2 should be used. WPA2 uses Advanced Encryption Standard (AES) instead of TKIP. AES is the best encryption available for wireless networks today and is currently being used by the U.S. Government to secure sensitive, but not classified information. WPA2 is also referred to as 802.11i.
Some vendors have established proprietary modes of securing information on a wireless network. While these systems may be very secure, keep in mind that these can become cumbersome and difficult to manage when working with a variety of vendors on an installation.
Wireless networks can have a profound affect when used in areas it would be otherwise impossible to deploy a surveillance system. Ace Internet Solutions (AIS) installed a wireless IP Surveillance system when it moved to an industrial park in Chicago. There had been a rash of vandalism and theft in the area, and to help combat the problem, the company wanted to install a surveillance system to monitor an area which encompassed nine square blocks.