CCNA Wireless 200-355 Official Cert Guide (2016)

As shown in Figure 17-2, you can enter the network name (SSID) and security and encryption types. You can also specify whether the PC should automatically connect to the network each time the SSID is detected, even if the SSID is not broadcast in any beacon frames.

Figure 17-2 Manually Configuring a New Wireless Network

The built-in Windows wireless client does not offer many specific configuration options; however, you might find more options by configuring the wireless adapter. From the Network and Sharing Center, select Change Adapter Settings to display a list of installed adapters. Right-click a wireless adapter and select Properties to display the adapter properties and a list of installed protocols, as shown in Figure 17-3. Click the Configure button to bring up a window of adapter driver properties. Finally, display the Advanced tab to display a list of parameters and values, as shown in Figure 17-4. The list of parameters varies from one adapter to another, depending on what settings the manufacturer offers.

Figure 17-3 Configuring Wireless Adapter Properties

Figure 17-4 Configuring Advanced Wireless Adapter Settings

You can verify the status of a wireless connection by right-clicking the wireless icon, then selecting Open Network and Sharing Center. If the machine is connected to a wireless network, you can click the Internet connection as shown in Figure 17-5. A new window will display the current network state, including IPv4 and IPv6 connectivity, the SSID, the wireless data rate offered, the signal quality, and a count of bytes sent and received. You can click the Details button to see more detailed information, as shown in Figure 17-6.

Figure 17-5 Displaying the Wireless Connection Screen

Figure 17-6 Displaying Detailed Connection Status Information

From the Wireless Network Connection Status window shown on the left side of Figure 17-6, you can click the Wireless Properties button to access configuration information about the wireless network profile that is in use. The Disable button can be used to disable the wireless network adapter, while the Diagnose button runs a series of tests that can be helpful in troubleshooting connection issues.

Usually it is a good practice to keep the wireless network adapter updated with a current driver version. You can verify the driver version in use by clicking the Properties button, then selecting the Driver tab as shown in Figure 17-7.

Figure 17-7 Verifying the Network Adapter Driver Version

Understanding Android Wi-Fi

Devices based on the Android operating system use a built-in driver and utility to manage connections to wireless networks. Android devices can discover a list of available networks and can manage manually configured networks too.

First, you should enable the wireless adapter by selecting Settings > Wi-Fi and then sliding the Wi-Fi switch to the on position, as shown in Figure 17-8. You can manage individual wireless connections from the same screen. The list shows the SSIDs of networks that have been discovered, in addition to those that are locally configured. After a network has been learned and connected to at least once, the device will automatically try to use it again in the future.

Figure 17-8 Displaying a List of Wireless Networks on an Android Device

You can manually add a new network by selecting the Add Wi-Fi Network link at the bottom of the network list. Enter the SSID and security parameters as shown in Figure 17-9, and then select the Save button. After a network has been learned, you can edit its properties by selecting the network from the list with a long-press and then selecting Modify Network Config. You can also delete a network profile by selecting it with a long-press and then selecting Forget Network.

Figure 17-9 Adding a Wireless Network on an Android Device

Android natively supports both WPA and WPA2 Personal and Enterprise security. Enterprise security commonly includes Transport Layer Security (TLS), Protected Extensible Authentication Protocol (PEAP), and Tunneled TLS (TTLS). Also, Android devices support Wi-Fi Direct, allowing direct communication with a small number of other devices in a peer-to-peer fashion, without requiring an AP. Although Wi-Fi Direct is derived from 802.11 ad hoc networks, it is incompatible with ad hoc networking because it supports additional negotiation and security features.

You can verify the status of a wireless connection by going to Settings > Wi-Fi. One of the Wi-Fi network names should be listed as “Connected.” You can display more information about it by selecting it, as shown in Figure 17-10.

Figure 17-10 Displaying the Wireless Status on an Android Device

Understanding MacOS X Wi-Fi

Apple devices use a built-in wireless adapter and a configuration utility to manage networks that are discovered and manually defined. You can view a list of discovered networks by clicking the wireless icon at the top of the screen, as shown in Figure 17-11. To connect to one of the networks, click its name. You can also turn the Wi-Fi adapter off and on from the links at the top of the list.

Figure 17-11 Displaying Discovered Wireless Networks in MacOS X

To access the wireless configuration utility, select System Preferences, and then select Network. Figure 17-12 shows an example, with all available network adapters listed down the left side. From this window, you can enable or disable the wireless adapter.

Figure 17-12 Accessing the MacOS X Network Properties

You can also select Wi-Fi and then click the Advanced button to display and edit the network connection configurations. The advanced settings window, as shown in Figure 17-13, has seven tabs across the top. The Wi-Fi tab contains a list of preferred networks—SSIDs that have already been configured. The networks will be tried in sequential order; you can change the order by dragging networks up or down in the list.

Figure 17-13 Displaying a List of Preferred Wireless Networks

You can create a new wireless network by clicking the + (plus sign) button. As shown in Figure 17-14, you can enter an SSID and security parameters for the new network profile.

Figure 17-14 Creating a New Wireless Network Profile

Sometimes you might need to verify the network adapter software version or wireless capabilities. You can do that by clicking the Apple logo in the upper-left corner of the screen. Next, select About This Mac and the Overview tab, as shown in Figure 17-15. Detailed wireless information can be displayed by clicking the System Report button. In the report output, select Network > Wi-Fi, as shown in the example report in Figure 17-16.

Figure 17-15 Displaying System Information in MacOS X

Figure 17-16 Displaying a Report of Wi-Fi Network Parameters

Understanding Apple iOS Wi-Fi

Apple iPhones running iOS can connect to Wi-Fi networks using a built-in network adapter and driver. You can view and control the Wi-Fi connectivity by pressing the home button and selecting Settings, as shown in Figure 17-17. Select Wi-Fi to manage the connections.

Figure 17-17 Accessing Wireless Settings on an iOS Device

Figure 17-18 shows an example list of wireless networks that have been discovered. If the device is connected to a network, a check mark will be shown to the left of the network name. You can select a network name and then select the Join or Forget link to connect or disconnect from the SSID. You can also manually define a network by selecting Other at the bottom of the network list. Enter the network name and security parameters as shown in Figure 17-19, then select Join to connect.

Figure 17-18 Displaying a List of Wireless Networks on an iOS Device

Figure 17-19 Manually Defining a New Network on an iOS Device

When the iOS device is connected to a network, you can display basic information about it by selecting the network name in the Wi-Fi settings screen. Figure 17-20 shows the IP addressing parameters for the connection named “foxtail.” The device will not display detailed information about the wireless adapter and the current RF parameters natively; you have to install a third-party application to do that.

Figure 17-20 Displaying Connection Information on an iOS Device

iOS devices support WPA and WPA2 Personal and Enterprise security and EAP-TLS. Wi-Fi Direct is also supported for impromptu peer-to-peer communication with other devices, without the need for an AP.

Cisco Compatibility Extensions

The wireless clients described in the previous sections are fairly straightforward; the client has a wireless network adapter and controls the SSID and wireless security that are used to associate with an AP. Beyond that, the AP can make a safe assumption that the client complies with the 802.11 standard and supports certain data rates, but it knows little else about the client and its capabilities. Just like the AP, the client device is likely certified by the Wi-Fi Alliance for one of the 802.11 rate protocols (as in 802.11b/a/n/ac), making them compatible.

For example, without thorough testing, how do you know whether a wireless client and its driver software release support Wi-Fi Protected Access Version 2 (WPA2) with EAP Transport Layer Security (EAP-TLS) or some other security scheme? How do you know whether a client can optimally transport audio and video over wireless? Suppose that your enterprise just purchased several hundred wireless communication or medical devices. How can you be certain which wireless functions and security features the devices support?

To remove some of the unknowns, Cisco created the Cisco Compatibility Extensions (CCX) program. Cisco defines a set of features as part of a specific CCX version. Wireless device manufacturers can implement the features in their devices and then submit their devices for testing and validation. If a device passes the interoperability tests, it receives a “Cisco Certified Compatibility” designation.

The CCX program really has two goals:

Take advantage of Cisco enhancements and innovations above what is defined in the 802.11 standard

Verify that a client supports each enhancement correctly

Over time, Cisco has developed CCX in phases or versions. To date, there are five versions, each building on its predecessor with an increasing set of features. Table 17-4 lists some of the 70 features, along with the CCX versions that support them. Notice how the more traditional and general features such as 802.11 are supported in all versions, essentially over a long period of time as WLAN technology has evolved. Features available only in v4 and v5 tend to be interactive, where the client works with the wireless infrastructure to report information about itself.

Table 17-4 Feature Support in CCX Versions 1–5

For example, management frame protection (MFP) addresses an inherent weakness in the management frames that an AP transmits. When a client receives a management frame, it implicitly trusts that the frame came from an AP and that the frame contents have not been tampered with. To secure management frames, both the AP and the client must participate to encrypt and authenticate each frame. Only CCXv5 clients are equipped to use frames protected with MFP.