ENTERPRISE EQUIPMENT: The Ball Has Just Started

Buying tips

Regulatory Guidelines: An enterprise must be aware of the regulatory guidelines governing the deployment of WLAN in India. For the record, 802.11b WLAN can be set up without government permission within the campus. The moment an enterprise decides to cross its building or campus, it needs to ask the government for a license. Also, regulations in India specifically permit the use of only 802.11b. The usage of 802.11a or 802.11g would require government clearance.

WLAN (802.11b) Tips
l	Range and Coverage: This can vary from 100–300 feet
l	Throughput: Important because its limited (theoretically 11 Mbps but actual 5.5 Mbps or even less as the bandwidth would be shared by many users)
l	Compatibility: with the existing networks
l	Interoperability of Wireless Devices: Different technologies or products using different frequency bands may not interoperate. Systems from different vendors may not interoperate even if they employ the same technology and the same frequency band.
l	Interference and Co-existence: Co-location of multiple wireless LANs could pose problems.
l	Security: Difficult to snoop, but not impossible. This must be addressed during installation itself.
l	Cost: Cost will depend on number of users and access points
l	Network Design: Scalability and in-building design should be taken into consideration
l	Battery Life of Mobile Platforms: End-user wireless products are usually designed to run off AC or battery power from their host laptop so insist on products that have design techniques that can maximize the host computer’s energy usage and battery life.
Source: VOICE&DATA GoldBook 2003

Radio Survey: Enterprises must carry out a radio survey of the area it wants its WLAN to cover. A survey is important for two reasons: one, it will help an enterprise design its network better and two, it would ensure that one network’s signal does not interfere with other networks in and around the proposed deployment site. An enterprise must ensure that radio signals do not cross the defined limits within which it wants the WLAN to work.
Site Survey and Network Design: Once the radio survey is done, the next important consideration should be the interior design structure of the site where WLAN is going to be set up. WLAN systems use radio frequencies (RF). And the distance over which RF waves can travel is not the function of the product alone. It also depends on the propagation path of RF. Even though RF waves are capable of penetrating most indoor walls and other physical obstacles, their range of coverage does depend on the indoor architecture of a building. In open spaces, each wireless LAN access hub can cover up to 300 feet, while in places with physical barriers like walls, a hub may be effective only up to 130 feet. This would naturally mean that access points should be placed strategically so as to overcome all physical barriers inside the building. Otherwise, users will not be able to enjoy the advantage of mobility or roam around freely in a building with their connected laptops. The enterprise should get the site survey conducted for verifying the coverage and estimating the number of WLAN access points required at the premise. This would depend on the topology of the location and the amount of throughput required.

What You Need to Buy
Prices (in Rs) for 802.11b products	D-Link	Cisco Linksys	Multi-tech
Wireless Access Point	5,500	4,800	5,520
PCMCIA Card	2,850	3,750	1,920

Do You Really Need WLAN?: In other words, an enterprise needs to know why it should deploy WLAN. WLAN can be more beneficial and productive if it is being deployed for running applications rather than plain mobile Internet access within the campus. Also, if an enterprise knows beforehand what it will do with WLAN, it will be in a better position to calculate the RoI on it.
Integration with Existing LAN: How an enterprise integrates WLAN with the existing wired LAN is also very important. The integration should be such that it facilitates seamless movement of a user from WLAN to wired LAN and vice versa. Also, services should be enabled on the WLAN in the same way as they have been on wired LAN.
Security Issues: Wireless LAN networks are prone to unauthorized access, breaking of encryption, and loss of data integrity. And except for a few of the more well-known vendors of WLAN products and solutions, many do not use any accepted security standards. So, an enterprise must ensure that it deploys only those WLAN products that adhere to widely accepted and proven security standards.
QoS: An enterprise must also ensure that any network that it deploys should have QoS built in. Among other things, this should mean that the WLAN must allow an enterprise to prioritize voice, data, and video on the network. Also, the network should be scalable.
Manageability: Managing a WLAN network can be a challenge as the network grows and adds more and more users. An enterprise must manage WLAN in the same way it manages its traditional LAN. In other words, it must look at managing both WLAN and wired LAN together from the same platform.
Throughput: Practically 802.11b does not support more than 5.5 Mbps bandwidth. Moreover, in a multi-user environment, this 5.5 Mbps bandwidth is shared among all the users and is not dedicated to a single user. Besides, as the user keeps moving away from a wireless LAN access hub, the bandwidth output keeps on decreasing. Naturally, all this rules out high-bandwidth applications. WLAN throughput is sufficient for applications like electronic mail exchange, access to shared peripherals like printers, Internet access, and access to multi-user databases and applications.

Experts panel

Shridhar Kadam, general manager, development and production support, D-Link India

Sudhir Narang, vice president, Cisco Systems