MITRE

Cost Benefit Issues in WirelessLocal Area Network (WLAN) Implementation

Presented toThe Society of Cost Estimating and Analysis

National Conference and Training Workshop

June 11-14, 2002

Scottsdale, Arizona

Stephen GrossThe MITRE Corporation

Economic & Decision Analysis Center

Email: sgross@mitre.org

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Agenda

Introduction Objective Background How WLANS Work WLAN Technology Option Customer Design Issues User Benefits Enterprise Benefits Security Issues Cost Consideration Typical ROI Summary References WLAN Glossary

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Introduction

A fundamental challenge facing information technology (IT) decision makers is identifying and implementing architectures, technologies, and processes that reduce the total cost of ownership (TCO) of corporate networks - one way is the wireless LAN (WLAN).

WLAN is not a replacement for the wired infrastructure, but it is a significant complement to it. Schools, manufacturing companies, hospitals, and government offices purchase WLAN systems for two predominant reasons: increase in user and IT team productivity.

WLANs consist of Network Interface Cards (NICs) and access points/bridges (end-user-to-LAN and LAN-to-LAN) for communications. NICs provide an interface between the end-user device (desktop PC, portable PC, or handheld computing device) and the airwaves via an antenna on the access point/bridge.

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Objectives

• To obtain a more thorough understanding of how wireless LANs are being implemented, corroborating and enhancing previous qualitative research conducted by several leading technology corporations

• To provide in-depth insight into the costs and benefits of wireless LAN implementation, as well as offering input into the challenges experienced by organizations who have deployed wireless LANs

• To show how cost savings and/or benefit associated with the deployment of wireless LAN technologies can be obtained and presented for organizations aspiring to justify expenditure for the deployment of wireless LANs

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Background Wireless Networking is an exciting technology that enables

computer users to access files stored on a network while moving around or working in a temporary office space—or enable one to access a network in other locations

A variety of applications have benefited from the WLAN implementation. Among these are:

- Home Usage - Wireless networks can save time and money

- Small business - entrepreneurs focus on growing their businesses and WLAN can grow with them Enterprise - Many larger corporations and manufacturing facilities found that significant benefits of their WLANs. In most instances, only a portion of the network is wireless

- LAN to LAN Bridging - Installing buried cable between buildings to provide connectivity may be difficult at times, but with wireless many companies are finding a quick and reliable solution.

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How WLANs Work

Wireless LANs use electromagnetic airwaves (radio and infrared) to communicate information from one point to another without relying on any physical connection.

In a typical WLAN configuration, a transmitter/receiver transceiver) device, called an access point, connects to the wired network from a fixed location using standard Ethernet cable.

At a minimum, the access point receives, buffers, and transmits data between the WLAN and the wired network infrastructure. A single access point can support a small group of users and can function within a range of less than one hundred to several hundred feet.

End users access the WLAN through wireless LAN adapters, which are implemented as PC cards in note-book computers, or use ISA or PCI adapters in desktop computers, or fully integrated devices within hand-held computers. WLAN adapters provide an interface between the client network operating system (NOS) and the airwaves (via an antenna). The wireless connection is transparent to the NOS.

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WLAN Cells Attached to a Wired Network

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WLAN Technology Options

Most wireless LAN systems use spread-spectrum technology, a wideband radio frequency technique originally developed by the military for use in reliable, secure, mission-critical communications systems.

Spread-spectrum is designed to trade off bandwidth efficiency for reliability, integrity, and security. There are two types of spread spectrum radio: frequency hopping and direct sequence.

A narrowband technology -- radio system transmits and receives user information on a specific radio frequency. Narrowband radio keeps the radio signal frequency as narrow as possible just to pass the information. Undesirable cross talk between communications channels is avoided by carefully coordinating different users on different channel frequencies.

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Customer Design Issues

THROUGHPUT -- Factors that affect throughput include airwave congestion (number of users), range, the type of WLAN system used, as well as bottlenecks on the wired portions of the WLAN. Typical data rates range from (1 to 11 Mbps).

COVERAGE -- Function of product design including transmitted power and receiver design and the propagation path, especially in indoor environments. Coverage for typical WLAN systems varies from under 100 feet to more than 500 feet.

INTEROPERABILITY -- Industry-standard interconnection with wired systems, including Ethernet (802.3) and Token Ring (802.5). Wireless LAN nodes are supported by network operating systems in the same way as any other LAN node-via drivers.

RELIABILITY -- Wireless data technologies have been proven in both commercial and military systems. While radio interference can cause degradation in throughput, such interference is rare. WLANs provide data integrity performance equal to or better than wired networking.

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User Benefits

The three primary reasons for the deployment* of wireless network access mirror the top benefits to both companies and employees:

Mobility/ Not tied to a location

Elimination of cabling/ wiring and associated costs

Provide employees with access to e-mail/ servers when away from office

*Based on Survey Data conducted – See Reference 2

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Enterprise Benefits

Companies consider cabling and its associated costs to be the primary benefit of WLAN

A second widely cited benefit is increased mobility and information access followed by gains in productivity.

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Security Issues

Many WLAN devices today do not have adequate security. The optional 40-bit RC4 ciphers in the original IEEE WLAN standard has been shown to be breakable*.

Ciphers implemented in software are not certifiable (by the DIA and the NSA) as militarily secure.

Most ciphers today encrypt the data, they do not encrypt the headers

*The RC4 40-bit cipher can be broken in just a few seconds working with an expensive machine. (RSA Burt Kalinski 6/22/2002)

ORiNOCO, which is a subsidiary of Lucent Technologies (now called Avaya Corporation). Their “Gold PC Card” can use a 128-bit RC4 cipher, which is considered essentially unbreakable.

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Selected Major WLAN Manufacturers*

Vendor Product Technology

Rate(s) of Communication

Nos. of Users Security List Price

Avaya (formerly Lucent)

Silver PC Card DSSS 802.11b 11, 5.5, 2, or 1 Mbps 64-bit RC4 $179

Gold PC Card DSSS 802.11b 11, 5.5, 2, or 1 Mbps 128-bit RC4 $199

ISA/PCI Adapter PC Card PC Card PC Card $69

Ethernet Adapter PC Card PC Card PC Card $229

RS-232 Adapter PC Card PC Card PC Card $329

WavePOINT-II AP32 users per PC Card

PC Card PC Card PC Card $995

Cisco (Aironet)

340 PC Card DSSS 802.11b 11, 5.5, 2, or 1 Mbps 40/128-bit RC4 $369

ISA/PCI Adapter PC Card PC Card PC Card $369

340 Access Point2048 users

PC Card PC Card PC Card $1,299

3ComAirConnect PC Card DSSS 802.11b 11, 5.5, 2, or 1 Mbps 40/128-bit RC4 $219

PCI Adapter PC Card PC Card PC Card $329

AirConnect AP63 users per AP

PC Card PC Card PC Card $1295

*As of Dec. 2001. Figures represent vendor published quotes and may not correspond to individual situations

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Costs Considerations

Cost Element Structure (CES) for WLAN Implementation

- Investment Network Interface Cards Access Points WLAN Management SW Test and Evaluation Costs

- O&S User Training IT training License Fees (HW & SW) Infrastructure maintenance

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Typical WLAN ROIs*

   Retail

Manufacturing Healthcare

OfficeAutomation

Education

Benefits per company(TY$M)

5.6 2.2 .94 2.5 .5

Costs per company(TY$M)4.2 1.3 .90 1.3 .3

Payback(# of months) 9.7 7.2 11.4 6.3 7.1

  

*Based on data published by the WLAN Association

• ROI = (Present Value of Net Savings) / (Present Value of Net Investments)

• On an annualized basis, the ROI is that discount rate at which the present value of the savings is equal to the present value of the investment cost through the life cycle of the project being evaluated.

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Multi-Site Consistency -- IT staff need to ensure WLAN setup, settings and configurations are similar and thus transparent to the worker and remain consistent throughout offices

- users will be able to seamlessly connect to enterprise-wide resources with little to no re-configuration

- mobile workers experience less down time- IT staff will be relieved of technical support

requirements APs and Client Management -- partner with a company

that can support the entire wireless infrastructure, including services such as a 24/7 help desk, remote administration capabilities and RF diagnostics

Wireless Card Interoperability -- 802.11b cards from various vendors can provide very different range limits. This is the result of the basic radio frequency (RF) performance of the radio’s transmitter/receiver.

Best Practices for Deploying WLANS

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Best Practices for Deploying WLANS - concluded

Security – 802.11 based products have experienced a great deal of criticism due to their vulnerabilities; security features may not be interoperable among various vendors. Security solutions differ depending on control over client card deployment.

Site Survey (SS) – SS can provide details about coverage and bandwidth performance at different locations

- Indicates where access points should be located

- Access point density will increase if an all time 11Mbps coverage area is required

- Clearly indicate where the fall back data rate of 5.5, 2 and 1Mbps areas are

Antenna Selection – select antenna for flexibility and robustness to optimize your applications

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Summary

Wireless LANs should be a high growth market over the next five years, both in terms of new customers and deeper penetration.

- Adopters have realized, and Intenders recognize, important benefits/advantages at both the corporate and employee levels.

Security has been, and remains, the overriding concern regarding wireless networking deployments.

VPN functionality/support ranks second behind 802.1x in relative importance to Organizational adopters and intended users.

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References

1. Wireless LAN ROI/Cost-Benefit Study, Sponsored by The Wireless LAN Association, October 1998

2. Wireless LAN Benefit Study, NOP Worldwide, Fall 2001, Conducted on Behalf of CISCO Systems, Inc.

3. Bing, Benny, 2000, High-Speed Wireless ATM and LANs, Artech House Publishers.4. Van Nee, Richard, Geert Awater, Masahiro Morikura, Hitoshi Takanashi, Mark

Webster, and Karen Halford, December 1999, “New High-Rate Wireless LAN Standards,” IEEE Communications Magazine, pp. 82-88.

5. Bugala,, Paul, April 2001, “Wireless LANs Management: Forecast and Analysis,” IDC.6. IEEE 802.11-1997, November 18, 1997, “Information Technology—Telecommunications

and Information Exchange between Systems, Local and Metropolitan Area Networks, Specific Requirements—Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications.”

7. IEEE 802.11a & b-1999, January 20, 2000, “Supplement to IEEE Standard for Information Technology—Telecommunications and Information Exchange between Systems, Local and Metropolitan Area Networks, Specific Requirements—Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications, High-Speed Physical Layer in the 5-GHz Band.”

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W20LAN Glossary

Access Point — A device that transports data between a wireless network and a wired network (infrastructure).

IEEE 802.X — A set of specifications for Local Area Networks (LAN) from The Institute of Electrical and Electronic Engineers (IEEE). Most wired networks conform to 802.3, the specification for Ethernet networks. The 802.11 committee completed a standard for 1 and 2 Mbps wireless LANs in 1997 that has a single MAC layer for the following physical-layer technologies: Frequency Hopping Spread Spectrum, Direct Sequence Spread Spectrum, and Infrared. IEEE 802.11 HR, an 11 Mbps version of the standard.

Independent network — A network that provides (usually temporarily) peer-to-peer connectivity without relying on a complete network infrastructure.

Infrastructure network — A wireless network centered around an access point. In this environment, the access point not only pro-vides communication with the wired network but also mediates wireless network traffic in the immediate neighborhood.

Microcell — A bounded physical space in which a number of wireless devices can communicate. Because it is possible to have overlap-ping cells as well as isolated cells, the boundaries of the cell are established by some rule or convention.

Roaming — Movement of a wireless node between two microcells. Roaming usually occurs in infrastructure networks built around multiple access points.

Wireless Node — A user computer with a wireless network interface card (adapter).