After your network device has been configured correctly, control the Internet dial-up with KInternet. On start-up, KDE loads KInternet. The program checks whether an Internet connection can be established. If this is possible, the application icon, a plug, automatically appears in the right part of the KDE panel. Depending on the state of the network connection, the panel icon changes appearance:

Right-click the KInternet panel icon to access its configuration menu. The YaST configuration dialog can be started via ‘Settings’+‘Configure with YaST’. After entering the root password, YaST starts. Depending on the access type, start the modem, ISDN, network, or DSL configuration of YaST.

If you are using an ISDN connection and you have selected ‘Channel Bundling’ in YaST, a second ISDN channel can be added to an existing connection with ‘Add link’. This doubles the transfer rate (although at a higher price). Activate channel bundling if you need to download large files. The activated channel bundling is evident from the red plus symbol at the top left corner of the KInternet icon.

If your computer has more than one network device and you have configured all of them with YaST, you can use the KInternet option ‘Interface’ to switch between these interfaces. You must have selected ‘User Controlled’ device activation in the appropriate YaST network dialog to do this. If you have multiple providers as well, choose them using ‘Provider’ in KInternet. Providers are also set in YaST.

Users who want to establish Internet connections automatically can use dial on demand (DoD). If this mode is selected, KInternet automatically connects to your Internet service provider (ISP) as soon as a request is submitted. After a certain time-out, the connection is terminated. A DoD connection is evident from the blue D at the bottom right corner of the KInternet icon.

	Cost Control
Note that DoD only makes sense if you have a flat rate Internet account. If that is not the case, connecting and disconnecting all the time can become very costly.

If you intend to use a wireless network card as your connection to the Internet, configure it using YaST as described in the Reference manual and make sure that the device activation in YaST is set to ‘User Controlled’. As soon as the interface is configured, you can use KInternet to control your wireless network connection, just as you would for normal network interfaces.

To access the WLAN functionality of KInternet, right-click the icon to open the menu. Select ‘Wireless Connection’ and a window showing two tabs opens. First, scan for suitable wireless networks you could connect to. Select the tab ‘Scan for Wireless Networks’, shown in Figure 4.6, “KInternet: Scanning for Wireless Networks”.

Figure 4.6. KInternet: Scanning for Wireless Networks

Start the scan with ‘Start Scan’. For KInternet to continuously scan the network environment, also select ‘Auto Refresh’. Acoustic feedback for each connection found can be activated via ‘Acoustic Scan’. Any connection found is displayed in the list window. Select one and click ‘Connect’ to connect to the selected network. If additional configuration efforts are needed to connect to the selected network, click ‘Start YaST’ to launch the YaST network module for wireless network devices.

The ‘Current Connection’ tab allows you to monitor the state of your current wireless connection. The left-hand view of this tab offers a summary of all connection parameters regarding network address and ESSID, signal quality, signal and noise level, channel frequency and speed, and encryption parameters, such as type of encryption and key length. Select any of these parameters in the tree structure and check the details displayed in the right part of the window.

Netapplet allows you to easily monitor and switch network connections available on your computer including wireless connections. Once the initial configuration of the network interfaces is done with YaST, Netapplet controls your Internet connectivity.

A typical Netapplet menu contains the following items that are displayed when you click the panel icon:

Successfully working on battery power requires a very sophisticated handling of the system resources by the operating system. Mobile hardware is optimized to allow a very flexible management of power usage by the CPU and other components. Depending on the environment in which the system is run, the power management can easily be adjusted in SUSE Linux using GNOME Battery Charge Monitor or KDE KPowersave.

Battery Charge Monitor allows you to send your machine into a hibernation state (‘Suspend Computer’) in which the entire system state is written to disk prior to shutdown. Once reactivated, this state is recovered. Configure the power management settings with ‘Power Management Settings’. The YaST Power Management module is launched enabling you to configure all power management settings centrally.

Using KPowersave, you can start the YaST Power Management module and issue both a suspend to disk or a suspend to RAM (if configured accordingly with YaST). You can change the CPU frequency policy, meaning your system either lets the CPU frequency drop when the system is idle and adjusts it dynamically if more CPU power is needed (set the CPU frequency policy to ‘Dynamic’), permanently keeps a low CPU frequency to save power (select ‘Powersave’ ), or permanently keeps a high CPU frequency for maximum CPU performance (select ‘Performance’). If you change the active power management scheme (‘Set Active Scheme’), all components of your system are part of the powersaving effort. A power management scheme includes settings for CPU frequency scaling, throttling, hard disk control, and system cooling. To start this program in a GNOME environment, enter kpowersave at the ‘Run Application’ prompt.

Your system needs to adapt to changing operating environments when used for mobile computing. A lot of services depend on the environment and the underlying clients must be reconfigured. Use the system configuration profile management (SCPM) framework to create different configuration profiles for all environments your machine is used in. Change the active profile using Profile Chooser. To modify your SCPM settings, select ‘Select YaST Profile Manager Module’ and enter the root password when prompted to do so. Start Profile Chooser in KDE using the main menu. In GNOME, enter profile_chooser at the ‘Run Application’ prompt.