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Campus wireless

Footloose on campus

Wireless technologies provide a number of benefits over wireline technologies for campus connectivity. We look at the available technologies and the way ahead. by Soutiman Das Gupta

"Although a wireline infrastructure is prefer-able in the campus when it comes to deploying bandwidth-intensive applications, a wireless solution has its own advantages," says Anand Mehta, Manager, New Business Areas Development, D-Link India Limited.

Using wired connectivity in a campus isn't always convenient. You may want to construct a new building or unit on the existing campus, add capacity by linking up a temporary office, move a business unit from one location to another, or want to connect buildings separated by a road or railway lines.

In such cases, the use of a wireline infrastructure can work out to be prohibitively expensive as you will need to dig trenches, buy expensive cable, and sometimes you may even have to wait for licenses or permits before work can commence. The use of a leased line is neither cost-effective nor worth waiting for in such cases.

Wireless technology options that can be considered include 802.11x and Radio Frequency (RF).

Variants

 

Leased lines are not reliable at remote locations, and our telephone bills were high. The VoWLAN solution is both cost-effective and reliable. We plan to implement Video Conferencing next
Satyen Naik, Asst. Manager (IS) Sumul Dairy Ltd

802.11b and 802.11g are the preferred technologies for Wi-Fi in campuses. 802.11g offers higher bandwidth than 802.11b, but both operate in the same 2.4 GHz spectrum.

A wireless link in the campus can be extended beyond the building with the help of strategically placed Access Points (APs). One AP typically covers a radius of 300 feet. So the requisite number of APs can be used to wireless-enable the desired area within a campus.

Criteria for Deployment

"An organization has to first profile the campus' connectivity needs. Then it has to determine what applications will be used on the wireless network, the amount of bandwidth that will be required, and the area that needs to be covered," says Shrikant Patil, Director, Solutions Group, of Intel in India.

The APs can be inter-connected with a wired infrastructure or with the help of additional APs. So at each location, one AP will provide bandwidth, and a second one will connect it to the next AP acting as a repeater.

In case of building-to-building connectivity, APs can be placed on the top of each building. In case a building is more than 300 feet away, an AP kept mid-way will act as a repeater. Some companies prefer to substitute the AP with an omni-directional antenna. But the basic functions and technology remain the same in that scenario as well.

Issues with Wi-Fi

The issues with Wi-Fi connectivity are authentication, privacy, service qualilty, roaming problems, and access control.

The Wired Equivalent Privacy (WEP) security system which forms part of the 802.11b standard does not provide adequate security for sensitive data. Although a lot of the issues have been resolved, it is not yet entirely secure.

In order to provide better authentication and privacy measures an organization can use authentication based on username and password combinations, digital certificates, smart cards, and secure token technologies depending upon individual security needs.

Different levels of access control can be deployed with the use of a gateway that sits between the AP and the wired infrastructure. The gateway can use controls such as RADIUS and LDAP for security.

Service quality and roaming issues can be resolved by better network planning and strategic placement of APs in the campus.

Wireless campuses in India

A number of Indian organizations have deployed wireless links in their campus networks and found the going easier than what a wired infrastructure would have allowed them.

LG Electronics India Ltd. has deployed an 802.11b campus WLAN solution at its 47 acre campus in Noida. The campus WLAN hosts business-critical applications such as an internal ERP system and Lotus Notes, and it is used to provide Internet access to LGEIL's plant and executive employees.

Sumul Dairy in Gujarat, a part of the Surat District Cooperative Milk Producers' Union Limited, deployed 12 Access Points (APs) at its two square km (approx.) campus. The WLAN lets the company share mission-critical data within internal departments like the boardroom, veterinary department, by-products depart-ment, finished products sections, artificial insemination department, and the ERP servers.

Jindal Strips Limited, a part of the Haryana-based steel conglo-merate, wanted to connect its Cold Roll Division with its HR and Administration Division. The two divisional offices were across the road, but a railway track was planted squarely between them.

At first the company used optic fibre links, but these were not very useful as the roads were continuously dug up for repairs and the intense heat from the furnaces was too harsh for the fibre.

The company deployed an 11 Mbps WLAN building-to-building bridge, omni-directional antenna, and other Wi-Fi equipment at the premises. The connectivity links are always up, they let the company share vital business data without downtime.

Listen to the radio

Radio Frequency links are point-to-point Line-Of-Sight (LOS) links that are ideally suited for connecting two buildings in a campus. They offer a wide range of frequencies. That said, companies need a license from the government before they can use RF links.

Wireless transceivers on both ends with a clear line of sight can transmit data across large distances (more than 500 metres). A bi-directional amplifier unit can be used to boost signals over long distances.

Voice over WLAN

Voice over WLAN (VoWLAN), or telephony over a wireless link is set to become a popular enterprise application. The application can improve group communications and reduce call costs within offices.

Although VoWLAN technology is suitable for large enterprises, it could be around three years before the technology is cheap enough to be adopted by small and medium enterprises.

The issue of latency in wireless links can be a hindrance to voice transmission due to delay. But the use of a voice gateway and bandwidth prioritisation techniques can provide better service quality.

Sumul Dairy, a 425 Crore organization which is a manufacturing unit for Gujarat Co-operative Milk Marketing Federation Limited, uses 802.11b links to connect its Head Office with units located at remote locations in Gujarat.
The link is used to transmit Oracle database information and e-mail. The company has also procured a license for voice communication and set up a voice gateway to make VoWLAN possible.

Satyen Naik - Asst. Manager (IS), Sumul Dairy, says, "Leased lines are not reliable at remote locations, and our telephone bills were very high. The VoWLAN solution is both cost-effective and reliable. In the near future, we plan to implement Video Conferencing facilities on the same network."

A research team of Media Lab Asia (MLA) has created an 85 km-long multi hop wireless corridor between Kanpur and Lucknow, called the Digital Gangetic Plain. It uses the 802.11b protocol and uses VoIP technology to provide the rural population access to Internet-based applications and low cost phone calls.

The way ahead

With the increased use of wireless technology in the campus, enterprises have to stop viewing wireless as an 'add-on' to the network infrastructure.

Campus wireless networks must be integrated into existing wired networks and be able to scale to support hundreds or even thousands of users over great distances.

"Companies can use a framework called a Structured Wireless-Aware Network (SWAN) for better integration. A SWAN is a comprehensive framework for deploying, operating, and managing hundreds to thousands of access points," says Devendra Kamtekar - Prinicpal Consultant - Cisco Systems.

This approach combines the switch and router infrastructure with the wireless network, to create an integrated 'wireless-aware' network. It extends the same level of security, management, ease-of-deployment, scalability, and reliability that customers have come to expect in their wired LANs to the world of wireless LANs.

The use of applications such as Voice over WLAN (VoWLAN) and video over WLAN extend newer applications to the wireless ne-twork, something that wasn't possible just a few years ago.

Soutiman Das Gupta can be reached at: soutimand@networkmagazineindia.com

 
     
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