Ad hoc network: A network consisting of nodes which communicate with each other over a wireless channel without any centralized control. The nodes may cooperate in routing each other's data packets. An ad hoc network is also called a multihop network for this reason.
An Ad hoc network is self-organizing and adaptive. This means that a formed network can be de-formed on-the-fly without the need for any system administration. The term “ad hoc” tends to imply “can take different forms” and “can be mobile, standalone, or networked.”
Bluetooth: A short-range wireless communication technology that communicates via a frequency hopping transceiver in the Industrial, Scientific, and Medical (ISM) band at 2.4 GHz. Bluetooth supports up to eight active devices in each subnet or piconet. One device in a piconet is picked as the Master and the rest serve as Slaves. The Slaves synchronize to the Master in time and frequency. Multiple piconets may interconnect to form a scatternet.
IEEE 802.11: The IEEE 802.11 specifications for WLAN technologies are focused on the two lowest layers of the OSI model because they incorporate both physical and data link components. All 802.11 networks utilize the same Medium Access Control (MAC), i.e., a set of rules that determines how to access the medium and send data.
802.11 defines multiple physical layers. The 802.11b physical layer uses Direct Sequence Spread Spectrum (DSSS). The 802.11b spec allows for the wireless transmission of approximately 11 Mbps of raw data in the unlicensed 2.4 GHz band. The spec has only 3 frequency channels that do not overlap.
The physical layers 802.11a and 802.11g both utilize Orthogonal Frequency Division Multiplexing (OFDM). The 802.11a and 802.11g specs allow for the wireless transmission of approximately 54 Mbps of raw data in the unlicensed 5 GHz and 2.4 GHz bands, respectively. 802.11a has 12 frequency channels that do not overlap, allowing denser installations then 802.11b. 802.11a has shorter range, but can often transmit at higher speeds at similar distances compared to 802.11b. Since 802.11g is backward compatible with 802.11b, only three non-overlapping channels are available.
PAN: The term Personal Area Network describes the small wireless networks facilitated by Bluetooth, which joins together a group of personal devices.
PKI: A Public Key Infrastructure can be set up to provide a wide range of
security services. As a minimum, a PKI should offer the following:
- Authentication:
- The proof of a binding of an identity to an identification tag. The binding is established by a trusted third party. An example of such a scenario in real life is the creation of a passport, where the person to whom the passport is issued represents the identity, and the passport itself is the identification tag. The trusted third party is the issuing government.
- Integrity:
- An assurance to the involved parties that the data were not modified or tampered with in transit.
- Confidentiality:
- Data travelling across a network should not be viewable or accessible for others than the sender and the intended recipient(s).
SSL: The Secure Socket Layer protocol is the most widely used mechanism to secure transmissions of data over the Internet. It was designed by Netscape Communications Corporation in the mid-90's, but its development and maintenance was taken over by the Internet Engineering Task Force in 1996. Now in version 3.1, SSL has been renamed Transport Layer Security
(TLS). TLS provides mutual authentication, data encryption, and data integrity services.
Wi-Fi: The Wi-Fi (“wireless fidelity”) Alliance started the Wi-Fi certification program to ensure that equipment claiming 802.11 compliance was genuinely interoperable. Wi-Fi-certified equipment has demonstrated standards compliance in an interoperability lab. Originally, the term was applied to devices that complied with 802.11b. The term is now also applied to 802.11a and 802.11g equipment that pass similar certification test suites.
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Last updated 15.06.08.
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