CCNA Wireless 200-355 Official Cert Guide (2016)

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1. Suppose that you need to set up an autonomous AP so that it will offer three different SSIDs to clients. The AP will be connected to a wired network infrastructure. Which one of the following is a true statement about the AP?

a. It can support only one SSID, which must be carried over an access link.

b. It can support multiple SSIDs over an access link.

c. It can support multiple SSIDs over an 802.1Q trunk link.

d. An autonomous AP needs a centralized controller to support SSIDs.

2. Which one of the following is a true statement?

a. An autonomous AP cannot connect to a DS.

b. An autonomous AP connects through a centralized controller.

c. An autonomous AP operates in a standalone fashion.

d. None of these answers are correct.

3. Which of the following ports are available on an autonomous AP? (Choose all that apply.)

a. Console port

b. Service port

c. Ethernet port

d. Dynamic interface

4. After looking at a sticker on the back of an autonomous AP, you see MAC C4:7D:4F:12:34:56 listed. Which one of the following is a safe assumption?

a. The string of numbers is the 2.4-GHz radio base MAC address.

b. The string of numbers is the 5-GHz radio base MAC address.

c. The string of numbers is the Ethernet port MAC address.

d. All of the above are correct.

5. Which methods can be used to assign an IP address to an autonomous AP? (Choose all that apply.)

a. DHCP

b. Static through the CLI

c. TFTP

d. DNS

6. If the IP address of an autonomous AP is not yet known, which of the following methods could you use to find it? (Choose all that apply.)

a. DHCP server logs

b. CDP

c. AP console CLI

d. AP management GUI

7. In its default configuration, which of the following is true of an autonomous AP? (Choose all that apply.)

a. Both radios are enabled.

b. Both radios are disabled.

c. No SSIDs are configured.

d. One SSID (“Cisco”) is configured.

8. Which of the following are correct statements about autonomous AP configuration? (Choose all that apply.)

a. Each AP radio must offer an identical set of SSIDs.

b. Each AP radio can offer a unique set of SSIDs.

c. Each AP must be configured with the IP address of its controller.

d. An IP address must be configured on the Ethernet0 interface.

e. An IP address must be configured on the BVI1 interface.

9. To convert an autonomous AP into a lightweight AP, which of the following is needed? (Choose all that apply.)

a. Enter the convert lightweight command in the AP CLI

b. A TFTP or FTP server

c. An appropriate lightweight code image

d. An appropriate autonomous upgrade image

10. To upgrade an autonomous AP to lightweight mode, which one of the following initial command keywords should be used from the CLI?

a.upgrade download-sw

b.copy flash: tftp:

c.archive download-sw

d.download upgrade-sw

11. Which one of the following methods can you use to manage a Cisco Meraki AP?

a. Console port

b. CLI via Telnet

c. Web browser opened to the AP’s IP address

d. Web browser opened to the Cisco Meraki cloud

12. When a new Cisco Meraki AP is first powered on, it automatically connects with which one of the following?

a. A Cisco wireless LAN controller

b. A TFTP server located at 10.0.0.1

c. The Cisco Meraki cloud network

d. Nothing; as an autonomous AP, it waits for you to configure its IP address

Foundation Topics

Autonomous APs are commonly used in small networks, such as a small office or a remote site. Because the APs are self-contained and self-sufficient, they are fairly easy to set up and configure. The end result is a decentralized, distributed architecture, where each wireless AP touches the wired network independently. Each AP is configured and managed independently too, which can lead to a management nightmare as the number of APs grows.

You can think of an AP as a translational bridge, where frames from two dissimilar media are translated and then bridged at Layer 2. In simple terms, the AP is in charge of mapping a service set identifier (SSID) to a VLAN, or in 802.11 terms, mapping a basic service set (BSS) to a distribution system (DS). This is shown in Figure 9-1, where the AP connects a client that is associated to the SSID “Marketing” with the wired network on VLAN 10. On the wired side, the AP’s Ethernet port is connected to a switch port configured for access mode and mapped to VLAN 10.

Figure 9-1 Bridging an SSID to a VLAN

This concept can be extended so that multiple VLANs are mapped to multiple SSIDs. To do this, the AP must be connected to the switch by a trunk link that carries the VLANs. In Figure 9-2, VLAN 10 and VLAN 20 are both trunked to the AP. The AP uses the 802.1Q tag to map the VLAN numbers to SSIDs. For example, VLAN 10 is mapped to SSID “Marketing,” while VLAN 20 is mapped to SSID “Engineering.”

Figure 9-2 Bridging Multiple SSIDs to VLANs

In effect, when an AP uses multiple SSIDs, it is trunking VLANs over the air to wireless clients. In the 802.11 space, the VLAN tag is replaced by the SSID. The autonomous AP then becomes an extension of an access layer switch because it bridges SSIDs and VLANs right at the access layer.

Initially Configuring an Autonomous AP

As a wireless engineer, you will likely have to install and configure an autonomous AP. Many Cisco APs can operate in autonomous mode by running an IOS image—much like many other Cisco products. You can configure an AP through any of the following methods:

A terminal emulator connected to the AP’s console port

Telnet or Secure Shell (SSH) to the AP’s IP address

Use a web browser to access a graphical user interface (GUI) at the AP’s IP address

As you read through this chapter, think about the different parameters you might have to configure on an autonomous AP. At a minimum, you would have to configure one or more SSIDs and some wireless security settings. In addition, you would have to set the transmit power level and channel number for each of the AP’s radios. Now think about your wireless network as it grows—manually configuring a handful of autonomous APs might not be difficult, but working out the channel reuse layout for 50 or 100 APs in the same building might become a nightmare.

Connecting the AP

Figure 9-3 shows the ports that are available on a typical access point. You should connect the Ethernet port to a switch port on the wired network. The console port can remain disconnected unless you need to use it. A sticker on the AP provides the model and serial numbers, as well as the Ethernet port’s MAC address.

Figure 9-3 Ports Available on an Autonomous AP

By default, an AP will try to use Dynamic Host Configuration Protocol (DHCP) to request an IP address for itself. If it is successful, you can connect to it and interact with its GUI or command-line interface (CLI). If not, the AP will use the static IP address 10.0.0.1/26. You can also use the console port to configure a static IP address on the BVI1 interface of the AP, but it is usually more flexible and convenient to let it request an address on its own.

The AP’s IP address will not be readily visible because the AP has no way to display it, other than through its user interface and configuration. To find the IP address, you can query the DHCP server that assigned it and look for the AP’s MAC address.

Suppose that an AP has MAC address 00:22:bd:19:28:dd. From the output listed in Example 9-1, the MAC address is bound to IP address 192.168.199.44.

Example 9-1 Finding an Autonomous AP’s IP Address