Best Wireless Network Devices
Wireless Local Area networks (WLANs) are the basis for most wireless networks. They allow mobile users and devices to connect to a Local Area Network (LAN) through a wireless connection which transmits data using high frequency radio waves. The process is similar to establishing a wireless Internet connection for home computers and laptops; likewise, a company can establish a WLAN allowing devices like computers and network cameras to connect to the network and transmit video.
WLAN standards are well defined, and devices from different vendors can work together, which allows for the vendor neutrality that end-users often request. The most commonly used standard is 802.11g, which provides higher transfer rates over greater distances than 802.11a and 802.11b. Keep in mind that higher frequencies shorten the distance that radio waves can reach.
While 802.11g is sufficient for full frame rate video, it operates at only 25 percent of a typical 100 Mbps wired connection. The next generation WLAN standard will be 802.11n and the “n” standard will greatly increase the speed of wireless data trans-missions. This will improve the functionality of wireless IP surveillance systems as it will be possible to transmit video at even higher frame rates.
Wireless Networks Types
There are three major types of wireless networks, each providing different benefits and functionalities. All three utilize wireless radio waves as the primary method for transmitting data, although there are a few other means of transmission.
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. 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.
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. Deploying a wireless point-to-multipoint system is much more cost efficient than a wired sys-tem 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. 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.
Networking Design -IP Surveillance System
Networks allow devices such as network cameras, servers and PCs to communicate with each other, sharing information and, in some cases, a common Internet connection. Network designs can take many forms and vary in terms of performance and security.
It is useful to think of building a network as a layering process, beginning with the physical cabling configuration and connections. The number of cameras, the physical environment, the sensitivity of the application, and the protocols and software will impact the operation of the IP surveillance network.
Networks Types
Networks can be local area networks (LANs), metropolitan area networks (MANs) or wide area networks (WANs). Each network covers a progressively larger area. For example, LANs exist within a building or company, while MANs could cover a campus or city center. WANs cover the largest areas—anything from multiple distant areas to the entire world. WANs of-ten connect several smaller networks, such as LANs and MANs. The largest WAN is the Internet.
Basic Network Layout
Networks are made up of cabling such as Ethernet or fiber, and equipment such as servers, routers and hubs. There are many ways to physically lay out networks, but the main four designs are bus, ring, star and mesh. You can determine (10,000 Mbit/s), which will soon be incorporated into network backbones. IP surveillance systems work with all of these standards, so as networks become faster, they will be able to support higher-quality video.
Another benefit of Ethernet cabling is Power over Ethernet (PoE), which powers devices through the network cables. This eliminates the need to install power outlets at camera locations and enables a more continuous power supply.
Sometimes a non-wired solution is beneficial, particularly for buildings where cable installation will damage the interior, or where cameras will be regularly moved. Another common use of wireless technology is to bridge two buildings or sites with-out expensive and complex ground works. Wireless LANs are available in a number of well-defined standards that allow for vendor neutrality. The most common standard is 802.11g, which provides higher transfer rates at greater distances than 802.11a and 802.11b.
Power Over Ethernet is a system which allows electrical power to be passed from a PSE (Power Sourcing Equipment) device along the ethernet connection to supply power to a PD (Powered Device). This allows a single cable to be used to provide both data connection and electrical power to compatible devices.
PoE Classifications:
PSE devices detect the indicated power range / classification of connected PDs and allocate the necessary maximum power based on the PDs classification
The PoE classifications are as follows:
Class 0: Current (mA) 0 to 4 Power (W) 0.44 to12.94
Class 1: Current (mA) 9 to 12 Power (W) 0.44 to 3.84 Class description: Very low power
Class 2: Current (mA) 17 to 20 Power (W) 3.84 to 6.49 Class description: low power
Class 3: Current (mA) 26 to 30 Power (W) 6.49 to 12.95 Class description: Mid power
Class 4: Current (mA) 36 to 44 Power (W) 12.95 W to 25.5 W Class description: High power
The PSE will always allocate the maximum power based on the classification of the Power Device.
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), Wi-Fi Protected Access (WPA), and Wi-Fi 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.
WPA — WPA was created as a response to flaws in WEP. WPA works with most wireless network interface cards. 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). AES is the best encryption available for wireless networks today and is currently being used by the U.S. Government.
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 man-age 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. Using the wireless IP surveillance system, AIS deployed a wireless option and later discovered an extensive drag racing operation that was using the industrial park late at night for races.
While wireless networks have many benefits, there are still a few drawbacks. Wireless networks can affect the frame rate and latency of video delivery, and bandwidth is affected by the distance from the device to the access point. Wireless networks are also susceptible to interference by other wireless technologies and systems.
However, wireless networks allow for cameras and other devices on the network to be moved quickly and easily without the need for expensive cabling. While there are still limitations and security concerns, they can still prove advantageous when used correctly for installations that would otherwise be too difficult or costly with wired networks. It is important to understand the benefits and challenges and analyze whether a wireless solution will meet your organization’s demands before installing the network.
