10 ways to prepare for a wireless rollout

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    Version 1.0March 17, 200810 ways to prepare for a wireless rollout

    By Debra Littlejohn Shinder, MCSE, MVP

    There are a number of reasons for a company to implement wireless networking. Wi-fi makes it much easier for

    workers to connect to the LAN from their laptops in conference rooms, break rooms, and other areas that may nothave wired Ethernet jacks (or may not have enough for the number of people present). A wireless network alsoprovides a way for you to allow visitors to access the Internet with their laptops or handhelds (for example, tocheck their e-mail).

    Rolling out a wireless LAN within your organization, however, is more complicated than just plugging in a wirelessaccess point (WAP). You need to address a number of factors in the planning stage to ensure both accessibilityand security. Here are some of the things you should consider as you prepare to go wireless.

    Determine who will use your wireless network

    The first step in planning your wi-fi deployment is to determine who will be using your wireless network. This canaffect network design. If the wireless network is primarily to give visitors Internet access, you will want to isolate itfrom your wired LAN, perhaps by placing it in a DMZ. If the wireless LAN is for the use of your workers, you willneed to give them access to resources on the wired corporate network without compromising the security of themain LAN.

    If both outsiders and employees need wireless, you may want to establish two separate WLANs to meet theneeds of each.

    Define the purpose(s) of your wireless network

    The next step is to look at what type of traffic will flow over the WLAN. This analysis is necessary before you canproperly plan for a reliable user experience. For example, if you plan to implement real-time communications suchas VoIP over the wireless network (VoWLAN) or engage in video conferencing over wireless, you will need toconsider quality of service (QoS) and network management tools to ensure that voice transmissions workproperly.

    Determine bandwidth needs

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    Remember that wireless is a shared bandwidth technology. Thus, bandwidth needs are dependent on the numberof simultaneous users as well as the type of network traffic being transmitted. You can use a packet analyzer to

    help calculate the amount of bandwidth required for specific applications. Some wireless equipment vendorsprovide planning tools that can help you estimate your bandwidth needs. You can also use the method describedat http://www.techworld.com/mobility/features/index.cfm?featureid=774&pagtype=samechan&categoryid=21 tocalculate the bandwidth capacity you need. Be sure to plan not just for current needs but for future growth, aswell.

    11Copyright 2008 CNET Networks, Inc. All rights reserved.

    For more downloads and a free TechRepublic membership, please visit http://techrepublic.com.com/2001-6240-0.html

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    10 ways to prepare for a wireless rollout

    Compare wireless standards

    There are several different wireless standards, commonly identified by the numbers assigned to them by theInstitute of Electrical and Electronics Engineers (IEEE). IEEE 802.11 defines wi-fi standards, and there are

    basically four standards in use. 802.11b was the most common; it provides for the lowest cost but is limited to 11or 22 Mbps data transfer speed. It has now been replaced in many cases by 802.11g, which is backwardlycompatible with b and provides for faster performance: up to 54 Mbps. Many modern laptops come with wirelessnetwork cards that support both b and g.

    802.11a also supports up to 54 Mbps, but it has a shorter range than b/g. Because it operates on the 5 GHzfrequency, while b and g operate at 2.4 GHz, it uses equipment that is not compatible with b and g. It does,however, have the advantage of less potential interference from the wide variety of devices that also use the 2.4GHz frequency.

    The newest wi-fi standard is 802.11n. It is also backwardly compatible and offers speeds of 100 Mbps and over. Ithas a somewhat longer range, but it is currently the most costly. Wi-fi equipment (access points and networkadapters) that support n are just beginning to become available.

    There are other wireless technologies such as Bluetooth (for very short range communications) and WiMax (for

    longer range networking), but companies will generally use one of the varieties of wi-fi for their wireless LANs. Ifyoure rolling out a brand new wi-fi network now, it may be best to go with 802.11n; however, youll also want toconsider existing equipment (such as laptops and handhelds that only support b/g).

    Consider coverage issues

    In a large building, youll need multiple access points to provide wi-fi coverage throughout. Youll need to do a siteassessment to determine where access points and repeaters (devices that boost the signal) should be placed toeliminate gaps in coverage. High gain antennas can also extend the wireless signal range, and they come in bothomnidirectional and bidirectional varieties.

    You should also consider whether there are areas that you dont want covered, such as the parking lot. Itspossible to use certain materials on walls to block RF signals. There is even a type of coating that can be paintedon to block signals ( http://emsectechnologies.com/press_releases/press1.php ).

    Address interference issues

    Because wi-fi is transmitted via radio signals, those transmissions can experience interference if other devices inthe vicinity are transmitting on the same frequency. The 2.4 GHz frequency thats used by 802.11b, g, and ntechnologies is also used by many common electronic devices, such as microwave ovens, cordless phones, andgarage door openers. You may be able to set the equipment to different channels to avoid interference.

    You should perform a site survey before deploying the wireless network to ensure that devices operating on thesame frequency are not placed in close proximity to your WAPs. Spectrum analysis tools can provide graphicdiagrams of existing RF signals.

    Choose a wireless equipment vendor

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    Selecting a vendor of wireless equipment is an important step in planning your wi-fi rollout. There are manyhardware vendors that make WAPs, wireless routers, repeaters, antennas, and wireless network adapters. Theseinclude Cisco, D-Link, and many others.

    2Copyright 2008 CNET Networks, Inc. All rights reserved.

    For more downloads and a free TechRepublic membership, please visit http://techrepublic.com.com/2001-6240-0.html

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    10 ways to prepare for a wireless rollout

    The Wi-Fi Alliance ( http://www.wi-fi.org/ ) certifies products to ensure that these products have been tested andmeet their reliability and compatibility standards. Although certified products from different vendors should worktogether, you may find that using products from the same vendor makes deployment go more smoothly andmakes technical support of users easier.

    Select the best security mechanisms8

    Security is a big issue that must be considered in rolling out a wireless network. Because wi-fi signals aretransmitted over the air, they are more vulnerable to interception and deliberate disruption than are packets sentover a wired network.

    Wireless security mechanisms include strong authentication and encryption schemes. Wi-Fi Protected Access 2(WPA2) encryption with Extensible Authentication Protocol/Transport Layer Security (EAP-TLS) authenticationusing RADIUS servers as defined by the 802.1x standard is a good practice for protecting wireless networks fromunauthorized access and interception. For even stronger security, you can use two-factor authentication via smartcards or tokens.

    For more information on securing wireless networks, seehttp://www.networkcomputing.com/channels/wireless/security/

    Ensure that IT personnel are trained to maintain your WLAN9

    Before rolling out the wireless network, you need to make sure that your IT personnel have the knowledge andskills to maintain, administer, and troubleshoot the wireless LAN. Wireless equipment vendors offer training andcertifications. For example:

    Cisco certification for Advanced Wireless LAN Field Specialist(http://www.cisco.com/web/learning/le3/le2/le41/le86/learning_certification_type_home.html ).

    Planet3Wi reless Certified Wireless Networking Professional (CWNP) and Certified Wireless NetworkAdministrator (CWNA) certifications in wireless networking ( http://www.cwnp.com/community/ )

    Conduct a pilot program before rollout

    Finally, before rolling out wireless access throughout the organization, its a good idea to conduct a pilot i, offeringwi-fi in a limited area to a limited group of users. This will allow you to identify potential issues and detect securityor usability problems. You can then address them on a smaller scale.

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    Debra Littlejohn Shinder is a technology consultant, trainer and writer who has authored a number ofbooks on computer operating systems, networking, and security. These include Scene of the Cybercrime: Computer Forensics Handbook , published by Syngress, and Computer Networking Essentials , published by Cisco Press. She is co-author, with her husband, Dr. Thomas Shinder, ofTroubleshooting Windows 2000 TCP/IP , the best-selling Configuring ISA Server 2000 , and ISAServer and Beyond .

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    Copyright 2008 CNET Networks, Inc. All rights reserved.For more downloads and a free TechRepublic membership, please visit http://techrepublic.com.com/2001-6240-0.html

    http://www.wi-fi.org/http://www.networkcomputing.com/channels/wireless/security/http://www.cisco.com/web/learning/le3/le2/le41/le86/learning_certification_type_home.htmlhttp://www.cwnp.com/community/http://www.cwnp.com/community/http://www.cisco.com/web/learning/le3/le2/le41/le86/learning_certification_type_home.htmlhttp://www.networkcomputing.com/channels/wireless/security/http://www.wi-fi.org/
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    10 ways to prepare for a wireless rollout

    Additional resources

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    Check out all of TechRepublic's free newsletters

    Build a secure and reliable Wireless LAN

    10 things you should know about VoIP over wireless

    Design a successful, secure wireless LAN (WLAN)

    Version historyVersion : 1.0 Published : March 1 7 , 2008

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    Copyright 2008 CNET Networks, Inc. All rights reserved.For more downloads and a free TechRepublic membership, please visit http://techrepublic.com.com/2001-6240-0.html

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