Network Interface Configuration
Configure radio interfaces via GUI

The Radio0-802.11A/B Settings are applicable to the 1100 and 1200 IOS APs. The 802.11B configuration page is shown in Figure , while the 802.11A is shown in Figure . Many of the IOS configuration tasks as settings can be applied in VxWorks .

If the Enable Radio is enabled, the access point sends packets through its 802.11a/b radio interface and monitors when other devices use the 802.11a/b radio interface to send packets. To change the administrative state of the Radio from up to down, choose Disable. To change the administrative state of the radio from down to up, choose Enable.

The Current Status Software indicates whether the interface has been enabled or disabled by the user. The Current Status Hardware indicates whether the line protocol for the interface is up or down.

The Role in Radio Network is where the role of the access point can be selected. Choose one of the three access point (root) settings if the access point is connected to the wired LAN .

Use the Data Rates setting to choose the data transmission rates. The rates are expressed in megabits per second. The device always attempts to transmit at the highest rate selected. If there are obstacles or interference, the device steps down to the highest rate that enables data transmission. For each of the rates, choose Require, Enable, or Disable .

The Transmit Power (mW) setting determines the power level of the radio transmission. The default power setting is the highest transmit power allowed in a regulatory domain. Government regulations define the highest allowable power level for radio devices. This setting must conform to established standards for the country in which the device is used. To reduce interference, limit the range of the access point, or conserve power, select a lower power setting.

Use the Limit Client Power (mw) to set the maximum power level allowed on client devices that associate to the access point. When a client device associates to the access point, the access point sends the maximum power level setting to the client. All settings are in mw.

Use the Default Radio Channel to define the channel. The available selection of radio channels are determined by the regulatory domain. The default setting is the least congested frequency. With this setting, the device scans for the radio channel that is least busy and selects that channel for use. The device scans at power-up and when the radio settings are changed. A specific channel setting can be selected from the Default Radio Channel drop-down menu.

The Least Congested Channel Search selection list is available only when the Default Radio Channel is set to the Least Congested Frequency. By default, all channels are selected and searched. To select more than one channel, hold down the Ctrl or Shift keys to highlight multiple channels.

When enabling World Mode Multi-Domain Operation (802.11B only), the device adds channel carrier set information to its beacon. Client devices with world-mode enabled receive the carrier set information and adjust their settings automatically.

The Radio Preamble (802.11B only) is a section of data at the head of a packet that contains information the access point and the client devices need when sending and receiving packets. Keep the setting on short unless there is a need to test with long preambles. If the radio preamble is set to short and a client that does not support short preamble associates, the access point will only send long preamble packets to this client .

The Receive Antenna and Transmit Antenna settings are shown in Figure . These will be covered more in depth in Module 7.

Select Enable to use Cisco Aironet 802.11 extensions. This setting must be set to Enable so that load balancing, MIC, and TKIP can be used.

For the Ethernet Encapsulation Transform, choose 802.1H or RFC1042 to set Ethernet encapsulation type. Data packets that are not 802.2 packets must be formatted to 802.2 with 802.1H or RFC1042. Cisco Aironet equipment defaults to using RFC1042 because it provides optimum interoperability .

Normally, an access point treats a workgroup bridge as an infrastructure device and not as a client. The access point uses the reliable multicast protocol to ensure delivery of all multicast packets. The extra traffic caused by reliable delivery limits the number of workgroup bridges that can be associated. Using the Reliable Multicast to WGB setting, select Disable to allow the workgroup bridge to be treated as a non-infrastructure device and thus allow the maximum number of workgroup bridges to be associated.

Public Secure Packet Forwarding prevents exchange of unicast, broadcast, or multicast traffic between protected ports. Choose Enable so the protected port can be used for secure mode configuration. To prevent communication between clients associated to different access points on the wireless LAN, protected ports must be configured on the switch connected to the access point.

The Beacon Period is amount of time between beacons in Kilomicroseconds. One Kusec equals 1024 microseconds.

The Data Beacon Rate (DTIM) setting, always a multiple of the beacon period, determines how often the beacon contains a delivery traffic indication message (DTIM). A traffic indication map is present in every beacon. The DTIM tells power-save client devices that a packet is waiting for them. If power save clients are active, the access point buffers any multicast traffics and delivers them immediately after the DTIM beacon. Power save nodes always wake for the DTIM beacons. The longer the time, the more buffering the access point does, and the longer the multicasts are delayed. If the beacon period is set at 100 (its default setting), and the data beacon rate is set at 2 (its default setting), then the device sends a beacon containing a DTIM every 200 Kusec.

Packet settings are shown in Figure . Advanced Repeater settings are shown in Figure .


Lab Activity

Lab Exercise: Configure Radio Interfaces through the GUI

In this lab, the student will use the Radio 802.11b-setting page to enter basic channel and data rate information for the AP radio. The Radio 802.11b page will also be accessed to enter basic settings for the transmit power, antennas, and operating thresholds on the AP.

Interactive Media Activity

Demonstration Activity: AP Radio Advanced

In this activity, students will learn about AP Radio Advanced.