Basics of Wireless Networking

Wireless Networking

1. Wireless networking:

Wireless LAN technology conforming to standard 802.11b is being used increasingly as the main standard for corporate internal wireless LAN networks. The bandwidth of 802.11b is 11 Mbps and operates at 2.4 GHz Frequency. The successor of this current 802.11b standard is 802.11a and it is designed to operate at faster speed and at a different frequency. Though 802.11a standard and the technology behind it has become available, 802.11b is still widely used today. Both 802.11b and 802.11a are compatible with each other and many companies deploying dual 802.11b and 802.11a devices.

Wireless networks can provide the following benefits:

• A cost efficient network deployment alternative. Installing a wireless network can be easier, less time consuming, and is frequently less expensive to install that a wired network because it eliminates the need to run Ethernet cable through walls and ceilings.
• A means to scale your client access resources with agility. Compared to a wired network, it is relatively easy to expand or decrease the size of a wireless network by adding or removing wireless APs. By contrast, to expand service in a wired network typically requires the installation of additional network switches or hubs as well as installing cable.
• The elimination of recurring telecommunications charges. To connect the networks in two buildings separated by a physical, legal, or financial obstacle, you can either use a link provided by a telecommunications vendor (for a fixed installation cost and ongoing recurring costs), or you can create a point-to-point wireless link by using WLAN technology (for a fixed installation cost but no recurring costs).
• The availability of network resources without the constraints associated with connecting client computers directly to the wired network. Some kinds of buildings, such as historical buildings, might be governed by building codes that prohibit the use of wiring, making wireless networking an important alternative. Additionally, a WLAN lets you extend your network into areas that cannot be easily included in the wired network; examples include courtyards and cafeterias.

Wireless network pros

• Very convenient in the home, especially for laptops
• Easy to set up (you can get your Internet Service Provider, or “ISP”, to set it up for you if you’re having problems, for an additional fee).
• Less clutter

Wireless cons

• Slower transfer rate
• Can ‘drop out’ occasionally
• Not as secure

Wired network pros

• Faster transfer rate
• More secure

Wired cons

• Requires a little knowledge to set up (but it could be argued that configuring wireless networks also requires at least a basic computer knowledge)
• Not convenient if you wish to use your laptop anywhere in the house

2. Benefits of wireless networking:

2.1 Useful in organizations such as hotels, hospitals, and manufacturing units that have constraints for laying cables.

2.2 Useful for small and medium companies that intend to relocate their premises according to needs. There are no cabling costs involved when relocating the Company premises when wireless networking is used.

2.3 Wireless networks are also useful for notebook users in an office environment. Having a wireless LAN in place saves mobile users the hassle of plugging into a docking station every time they want to access the network. Instead, they can access the network from anywhere in the building.

2.4 Warehouse Inventory management: It is possible to update the inventory in real time by using notebook computers with barcode readers. The inventory is updated in real time as the products come and go out of the storage space.

2.5 You can use PDA (Personal Digital Assistant) to access the network resources.

3. Security Concerns:

Being a wireless network, a wireless LAN has a few security risks that need to be taken care of while designing the network. Typical security risks can be broadly categorized below:

Insertion Attacks- Process of placing unauthorized devices on the wireless network without going through a security process and review.

Interception and monitoring wireless traffic: An attacker can sniff and capture legitimate traffic. By encrypting the data this type of attack can be minimized.

Jamming: Similar to DoS (Denial of Service) attacks, a wireless network may be subjected to jamming, where legitimate traffic gets jammed because illegitimate traffic overwhelms the frequencies, making it impossible for timely flow of legitimate traffic.

Comparison of Wireless LAN protocols

IEEE 802.11 is divided primarily into three sub-standards, viz. 802.11a, 802.11b, and 802.11g. The following table distinguishes the differences and similarities between these standards and Bluetooth. Bluetooth is an alternative wireless network technology that followed a different development path than the 802.11 family of standards.

Though 802.11a and 802.11b standards have been developed around the same time, 802.11b has become very popular due affordability of the hardware for small business and home networking. However, considering any future expansion, it is desirable to buy equipment that is capable of operating in duel modes (802.11 a/b).

Bluetooth supports a very short range (approximately 10 meters) and relatively low bandwidth (1 Mbps). In practice, Bluetooth networks PDAs or cell phones with PCs but not used widely for general-purpose Wireless LAN networking. The very low manufacturing cost of Bluetooth makes it a viable solution for wireless devices like PDAs and Cell phones. Note that the 801.11 and Bluetooth standards are incompatible with each other.

802.11a Wireless LAN Protocol Features

The first wireless LAN (WLAN) standard was created by the IEEE committee in 1997, and was called 802.11. However, 802.11 standard supported only up to 2 Mbps of bandwidth, and quickly became obsolete. Subsequently, IEEE created the 802.11a, and 802.11b standards. The following are the advantages of the IEEE 802.11a standard compared to 802.11b:

1. 802.11a uses 5GHz frequency band which is less crowded and hence has relatively smaller interference problem.

2. 802.11a supports up to 54Mbps of bandwidth, which is much faster than the 11Mbps bandwidth provided by 802.11b standard devices.

3. 802.11a offers as many as 12 non-overlapping channels. With more channels, larger number of users can be accommodated with no performance degradation.

Some of the disadvantages of using the 802.11a standard are:

1. Not many client devices such as note book computers, PDAs support 802.11a standard. Most of these support either 802.11b or Bluetooth standards.

2. It is more expensive compared to other contemporary technologies like 802.11b and Bluetooth.

3. 802.11a standards are not compatible with 802.11b. Hence, devices manufactured complying with 802.11a and 802.11b respectively, are not interoperable.

3. The distance covered will be slightly less compared to 802.11b due to higher operating frequency (5 GHz). Note that, higher the radio frequency, lower the propagation distance for a given output power.

You may consider using 802.11g in place of 802.11a for reasons of cross compatibility.

802.11b Wireless LAN Features

The first wireless LAN (WLAN) standard was created by the IEEE committee in 1997, and was called 802.11. However, 802.11 standard supported only up to 2 Mbps of bandwidth, and quickly became obsolete. Subsequently, IEEE created the 802.11a, and 802.11b standards. The following are the advantages of the IEEE 802.11b standard compared to 802.11a and Bluetooth wireless LAN:

· The 802.11b WLAN standard is widely supported by manufacturers, and very cost effective.

· Easy to set-up and maintain.

· Suits well for home segment due to lower costs and simple set-up.

The following are some of the disadvantages:

· Supports only up to 11Mbps bandwidth. Though the speed is sufficient for most applications, it limits the number of simultaneous users to a far less number compared to 802.11a.

· It operates in 2.4GHz frequency band, which is normally used by many appliances. Hence, it is more interference prone compared to 802.11a.

· Doesn't provide suitable scalability required in business environment.

802.11g Wireless LAN Protocol Features

The IEEE's 802.11g standard is a higher-bandwidth successor to the popular 802.11b, or Wi-Fi standard. 802.11g operates at a maximum speed of 54Mbps whereas 802.11b has a maximum speed of 11Mbps (Megabits/sec). An 802.11g access point compatible with both 802.11b and 802.11g clients. As a result, a laptop computer with an 802.11g card will be able to access existing 802.11b access points as well as new 802.11g access points.

The following are the main advantages of 802.11g over 802.11b:

· Higher bandwidth at 54 Mbps,

· Cheaper than 802.11a, and costs close to 802.11b. 802.11g uses 2.4GHz frequency band, just like 802.11b.

· Backward compatible with 802.11b standard

The main disadvantages are:

· Higher cost compared to 802.11b (at least by 50%)

· Not yet widely supported by the client machines such as laptops, and PDAs.

Consider the availability of dual band devices while making any procurements. Devices compatible with both 802.11a and 802.11g (inherently compatible with 802.11b) are a good buy considering future expansion and compatibility in diverse network environments.

Bluetooth Wireless Networking

Bluetooth is an alternative wireless network technology that followed a different development path than the 802.11 family of standards. Bluetooth offers more flexibility than 802.11b but on a smaller range and speed. Its bandwidth is only 500Kbps, and its range is only 10 meters (30 feet). Devices with a Bluetooth radio and an antenna can speak to each other with little or no preparation. For example, conference attendees can readily transfer files across a table using their Bluetooth-enabled notebooks. You can also send a file to a Bluetooth-enabled printer without downloading drivers. Bluetooth may soon be a standard interface on many cell phones, handheld computers, and even home appliances. However, it is going to take sometime before the hardware and software issues are resolved completely. Bluetooth operates at 2.4GHz, and is subject to the same interference problems as 802.11b and 802.11g. Compare the WLAN technologies.

IP Telephony

Business organizations have traditionally separated their voice and data networks, doubling the cost of equipment and maintenance, support staff and training. However, voice over IP networks is being increasingly used by Individual and Corporate users. With IP telephony, it is possible to remove the costly PBX and replace it with a voice and data gateway implementing IP Telephony. Now a days, most routers that are used with data networks are coming with voice capability.

By using appropriate gateway, voice and data can be multiplexed and carried together without the need for a separate voice carrier. This in turn reduces the equipment, maintenance, and running costs significantly. Typical applications include Central office and branch office communications, call centers, and remote communications.

Benefits of IP telephony:

· Significant reduction in the cost compared to discrete voice and data networks.

· Reduction in the maintenance, support and training of personnel associated with voice and data networks

· Unified messaging using state of the art technology

· Better return on investment (ROI).

· Increased functionality with value added services such as SMS, and others.