Tài liệu môn Thiết Kế Mạng - Võ Tấn Dũng (votandung) CCNA_WLAN tài liệu, giáo án, bài giảng , luận văn, luận án, đồ án,...
Chapter 7: Basic Wireless Concepts and Configuration CCNA Exploration 4.0 Objectives • Describe the components and operations of basic • • • wireless LAN topologies Describe the components and operations of basic wireless LAN security Configure and verify basic wireless LAN access Configure and troubleshoot wireless client access Học viện mạng Bach Khoa - Website: www.bkacad.com The Wireless LAN Học viện mạng Bach Khoa - Website: www.bkacad.com Why Use Wireless? • Business networks today are evolving to support people • • • who are on the move Mobility environment: where people can take their connection to the network along with them on the road There are many different infrastructures (wired LAN, service provider networks) that allow mobility like this to happen, but in a business environment, the most important is the WLAN People now expect to be connected at any time and place Học viện mạng Bach Khoa - Website: www.bkacad.com Wireless Technologies Học viện mạng Bach Khoa - Website: www.bkacad.com Wireless Will Be Everywhere WAN (Wide Area Network) MAN (Metropolitan Area Network) LAN (Local Area Network) PAN (Personal Area Network) Học viện mạng Bach Khoa - Website: www.bkacad.com Wireless LAN Học viện mạng Bach Khoa - Website: www.bkacad.com Comparing a WLAN to a LAN • In an 802.3 Ethernet LAN, each client has • a cable that connects the client NIC to a switch The switch is the point where the client gains access to the network In a wireless LAN, each client uses a wireless adapter to gain access to the network through a wireless device such as a wireless router or access point Học viện mạng Bach Khoa - Website: www.bkacad.com What is WLAN RF Technology? Học viện mạng Bach Khoa - Website: www.bkacad.com Modulation Học viện mạng Bach Khoa - Website: www.bkacad.com 10 Systematic Approach to WLAN Troubleshooting • Step - Eliminate the client device as the source of the • • problem Step - Confirm the physical status of WLAN devices Step - Inspect wired links Học viện mạng Bach Khoa - Website: www.bkacad.com 61 Updating the Access Point Firmware Học viện mạng Bach Khoa - Website: www.bkacad.com 62 Incorrect Channel Settings Học viện mạng Bach Khoa - Website: www.bkacad.com 63 Incorrect Channel Settings: Solution Học viện mạng Bach Khoa - Website: www.bkacad.com 64 Solving RF Interference Học viện mạng Bach Khoa - Website: www.bkacad.com 65 Solving RF Interference • Site Surveys Học viện mạng Bach Khoa - Website: www.bkacad.com 66 Site Survey • Two categories: Manual and utility assisted • Manual site surveys can include a site evaluation to be followed by a more thorough utility-assisted site survey A site evaluation involves inspecting the area with the goal of identifying potential issues that could impact the network Specifically, look for the presence of multiple WLANs, unique building structures, such as open floors and atriums, and high client usage variances, such as those caused by differences in day or night shift staffing levels • Note: you not conduct site surveys as part of this course Học viện mạng Bach Khoa - Website: www.bkacad.com 67 Access Point Misplacement Học viện mạng Bach Khoa - Website: www.bkacad.com 68 Access Point Misplacement: Solution Học viện mạng Bach Khoa - Website: www.bkacad.com 69 Access Point Misplacement: Solution • Ensure that access points are not mounted closer than 7.9 inches (20 • • • • • • cm) from the body of all persons Do not mount the access point within feet (91.4 cm) of metal obstructions Install the access point away from microwave ovens Microwave ovens operate on the same frequency as the access point and can cause signal interference Always mount the access point vertically (standing up or hanging down) Do not mount the access point outside of buildings Do not mount the access point on building perimeter walls, unless outside coverage is desired When mounting an access point in the corner of a right-angle hallway intersection, mount it at a 45-degree angle to the two hallways The access point internal antennas are not omnidirectional and cover a larger area when mounted this way Học viện mạng Bach Khoa - Website: www.bkacad.com 70 Problems with Authentication and Encrytion Học viện mạng Bach Khoa - Website: www.bkacad.com 71 Problems with Authentication and Encrytion Học viện mạng Bach Khoa - Website: www.bkacad.com 72 Problems with Authentication and Encrytion Học viện mạng Bach Khoa - Website: www.bkacad.com 73 Summary Học viện mạng Bach Khoa - Website: www.bkacad.com 74 Học viện mạng Bach Khoa - Website: www.bkacad.com 75 ... Học viện mạng Bach Khoa - Website: www.bkacad.com 11 802.11b Direct Sequence Modulation Học viện mạng Bach Khoa - Website: www.bkacad.com 12 2.4-GHz Channel Sets Học viện mạng Bach Khoa - Website:... viện mạng Bach Khoa - Website: www.bkacad.com 17 802.11a 5-GHz Frequency Bands Học viện mạng Bach Khoa - Website: www.bkacad.com 18 802.11a Access Point Coverage Học viện mạng Bach Khoa - Website:... UNII-1 and UNII-2) Học viện mạng Bach Khoa - Website: www.bkacad.com 20 Wireless standards Học viện mạng Bach Khoa - Website: www.bkacad.com 21 Wireless Infrastructure Components Học viện mạng