Có 140+ tài liệu thuộc chủ đề "định tuyến giao thức"
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62 CCNA Wireless Official Exam Certification Guide. As you can see, bridges are a good way to connect remote sites. However, suppose that you are operating in a point-to-multipoint topology, and the central site experiences con- gestion. Who suffers? Just the central site? Just the remote site? No. When two remote sites communicate through a central site, the central site...
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As soon as the real data gets there, it uses only one of the antennas.. Most of the time this happens with a single radio in the AP and two antennas connected to it. This is important because the two antennas cover the same area. You wouldn’t try to cover two different areas with the same radio. Additionally, the antennas...
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Note: For more information on the history of the Yagi-Uda antenna, see http://en.. You can clearly see the butterfly-type pattern in the figure. Notice that there is also some coverage on the back side of the antenna, even though it is designed as a directional an- tenna. This fact can be useful if you want to test under the antenna.....
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The 802.11 Protocol Family Overview: A brief overview of the 802.11 family of WLAN protocols.. The Original 802.11 Protocol: A look at the original 802.11 protocol.. The 802.11b Protocol: A look at the 802.11b protocol.. The 802.11g Protocol: A look at the 802.11g pro- tocol and how it operates with 802.11b clients.. The 802.11a Protocol: A look at the 802.11a...
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How 802.11g Interacts with 802.11b. One interesting point about 802.11g is that, although it is backward compatible with 802.11b clients, you probably do not want it to be because if you must support 802.11b clients, the entire cell suffers. In fact, if the average bandwidth is 22 Mbps in an 802.11g cell and an 802.11b client shows up, the cell...
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Wireless Frame Transmission: A discussion of how frames are transmitted on a wireless LAN.. Wireless Frame Headers: A look at the headers used in wireless transmissions.. Frame Types: Putting together how the frame types are used in managing and connecting to a network.. It is not likely that in your everyday activity you will be following the flow of traffic....
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In this situation, you can actively scan a network to deter- mine if the cell you are looking for is accessible. As you can tell in the figure, the client is looking for a wireless cell with the SSID of “Car- roll.” This client sends a probe request and the AP, upon receiving the probe request, issues a probe response....
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DECT devices in the U.S. How many Bluetooth devices can be paired?. Bluetooth operates in which frequency band?. Bluetooth 2.1 + EDR c. ZigBee operates in which frequency band?. True or false: WiMax interferes with 802.11 LANs because it operates on the same frequency band.. WiMax is defined in which IEEE specification?. 802.15.1 b. 802.16e c. Cordless Phones. Cordless phones...
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The Wireless Network Road Trip: A look at the packet delivery process on a wireless-to-wired net- work.. Delivering Packets from the Wireless to Wired Network. The Wireless Network Road Trip 1–4. This chapter focuses on delivery of packets to the wired network and the path that traffic will traverse. If you score 80 percent or higher, you may way to...
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That ARP response is sent back as a unicast message, so the switches in the path are going to forward it directly to the port that leads back to the wireless client, rather than flooding the frame out all ports. Eventually the frame is received by the WLC, and it must be re- built as an 802.11 frame. When the...
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Review the most important topics from this chapter, noted with the Key Topics icon in the outer margin of the page. ch09.qxp PM Page 162. 1 Configuring VLANs, http://tinyurl.com/588kw ch09.qxp PM Page 163. Describe the basics of the Cisco Unified Wireless Network architecture (Split MAC, LWAPP, stand-alone AP versus controller-based AP, specific hardware examples). Describe the Cisco Mobility Express Wireless...
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Access points. Network services APs in the CUWN. The lightweight AP is controlled and monitored by the Cisco Wireless LAN Controller (WLC). The AP com- municates using a special protocol called the Lightweight AP Protocol (LWAPP) to relay information to the WLC about the coverage, the interference that the AP is experiencing, and client data about associations, among other pieces...
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Figure 10-8 Cisco 4400 Series Wireless LAN Controller. This can be anywhere from six to 300 access points per controller. The Cisco 44xx Series WLC. The Cisco 44xx series Wireless LAN Controller, shown in Figure 10-8, is a standalone ap- pliance.. And it can support up to 5000 MAC addresses in its database.. You can manage the device via the...
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At a high level, and after the AP has an IP address, the phases of LWAPP operation include these:. An AP sends an LWAPP discovery request message. The AP chooses a controller based on the response received and sends a join request.. The WLC receiving the LWAPP join request responds to the AP join request with an LWAPP join response....
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You can also have a primary and backup port on a controller. If the primary goes down, you can use the backup.. Take the same example as N + N but add a third controller, WLC-BACKUP, that every AP points to as the tertiary.. The AP Is Joined, Now What?. You can change the mode by navigating to Wireless >....
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Figure 12-3 Edit All Page. In Figure 12-3, two controllers are listed on the Edit All page. So what happens if a user moves to another mobility domain? Because a controller in a different mobility domain does not have information about the client, the client must reassociate. When the client reassociates, it will most likely get a new IP address,...
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Controller Terminology: A discussion of the terminology used with Cisco controllers.. Connecting to the Controller: How to connect to a Cisco controller via the CLI and web interfaces.. Configuring the Controller Using the Web Inter- face: How to build a simple guest network, allow connections, and control where access is permitted.. Monitoring with the Controller: A look at the Monitor...
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When the HTML interface is accessible, you can upgrade the code on the controller. Of course, you can also manually update the image, as seen in Step 3. Alternatively, you can change the active boot image or clear the configuration file.. Initially, the controller looks for a configuration file. If the controller finds such a file, it loads it and...
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Figure 13-8 WLAN Configuration Tabs. Figure 13-9 Listing WLAN Profiles. Success! You now have a functional WLAN, as Figure 13-9 illustrates. One AP is in the lobby, and the other is in the research lab. You do not want anyone to access the AP in the research lab using the GUESTNET. To begin, though, you should identify which AP is...
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Figure 13-20 Radio Statistics. 802.11a/n Radios / 802.11b/g/n Radios: The 802 Radios links provide a list of APs with that specific type of radio.. Looking further into the 802.11a/n Radios and 802.11b/g/n Radios options, you can gain even more information by selecting the Details link for a radio from the Monitor Sum- mary page. Looking more closely at Figure 13-19,...