User's Guide

Introduction
8
See “Set up and join ad hoc networks” on page 17 for how to set up an ad hoc
network.
SIM services
SIM services refers to a service which enables you to access the Internet via your
wireless service provider’s own public network. Your wireless provider may, for
example, offer you the possibility to check data from your company intranet, send
and receive e-mail, and save documents. SIM services are usually available in
public places such as hotels, airports, railway stations, business centers, and
corporate buildings.
Note: Before you can take advantage of the SIM services, you must
subscribe to these services from your wireless provider and obtain
instructions for use.
A SIM card is used as a means for user identification: the data stored on the SIM
card is read, and if valid, you are allowed to connect to the Internet and intranets.
The SIM card is provided by the wireless provider.
Accounting data, such as used access time and/or transferred data, is passed from
the network on to the wireless provider for billing purposes. Accounting begins
when the wireless station is authenticated and ends when the wireless station
logs off.
Note: The actual invoice for services from your wireless provider may vary,
depending upon network features, rounding-off for billing, taxes and so
forth.
Security in WLAN
Security issues should always be carefully considered to ensure the secure
transmission of data in both wired and wireless LANs. In current wireless systems,
for example, WLAN access points need to authenticate wireless stations to
Figure 2 - Ad hoc network