Hiperlan

As for encryption, WEP uses a 24-bit initialization vector which is added to the WEP key. This vector changes in each packet sent by providing a basic data encryption level. Unfortunately both security forms in WEP have some problems.

In terms of authentication,

WEP supports no more than four keys and there is no mechanism for updating them regularly.

The same keys are used by several clients and access points and are never changed. This means that bad users can hear the flow of communication and using SWs that are easily found they can be authenticated at access points.

In terms of encryption,

WEP uses an RC4 algorithm which is of the onetime-pad type. According to this type of algorithm the process is repeated at least every 224 packets. For access points with significant amounts of traffic this amount of packages is only a matter of hours. Consequently, attackers monitoring data flow can identify two messages that are encrypted with the same 24-bit initialization vector and thus can find the keys and decrypt the original text.

Companies need to understand that WEP is not designed to create end-to-end security. WEP should be used in conjunction with other existing security mechanisms such as firewall, VPN and application-level security. Here are some criteria to consider when using WEP as part of WLAN security:

Companies need to understand that WEP is not designed to create end-to-end security. WEP should be used in conjunction with other existing security mechanisms such as firewall, VPN and application-level security. Here are some criteria to consider when using WEP as part of WLAN security:

• Use a firewall to separate the wireless network from the cable network.

• Make wireless users authenticate to VPNs before accessing the corporate network.

• Incorporate security even at the application level for confidential information.

• Implement dynamic WEP key refresh.

• Do not assume that WEP guarantees complete data security.

However, not all security issues in WLAN are attributed to WEP problems. Many of the problems have turned out to have occurred because companies have misused this mechanism or have not used it at all.

802.11a

802.11a is the alternative standard of 802.11b but at higher speeds. This standard transmits in the 5 GHz spectrum and at a speed of 54 Mbps. Unlike 802.11b it uses OFDM modulation technology. This fact makes the standards a and b unsuitable for each other. Practically creates communication barriers between networks and devices that use different standards a and b. However both standards can even coexist by combining the two into a single chip.

802.11g

It is a fast wireless communication standard that uses the 2.4 GHz spectrum and reaches speeds of up to 54Mbps. For speeds up to 11 Mbps it uses DSSS as a modulation technique, while for higher speeds it uses a more effective technique such as OFDM. In addition to high speed, one of its most important advantages is its compatibility with the popular 802.11b standard. But if such a communication occurs, the network speed does not exceed 11Mbps because it is limited by 802.11b.

802.11n

They offer a wider range of wave distribution and operate at 2.4GHz and 5GHz frequencies. The first product was approved in 2009.

Other standard 802.11 are

• 802.11

• 802.11f

• 802.11h

• 802.11i. Improves security and authentication mechanisms using the MAC level.

HomeRF

It is a wireless technology designed for home networks. HomeRF uses the SWAP (Shared Wireless Access Protocol) protocol. One of the most important improvements to SWAP is its support for high quality voice communication.

This allows cordless phones to use the same network infrastructure as computers and provide telephone services such as phone calls, call identification, ringtones, and more.

HomeRF networks use the 2.4 GHz frequency and encounter the same interference as the 802.22b networks. They have coverage up to 50 meters and a maximum speed of 10 Mbps. However this standard did not spread much due to the massive spread of the 802.11b standard.

ETSI proposed the HIPERLAN (High-Performance Radio Local Area Network) standard in 1992 to meet the needs for fast communication in wireless communication with a narrow range. The first version called

HIPERLAN / 1 is based on Ethernet standards, while radio transmission is obtained from GSM. Use the 5-GHz spectrum. Since this standard did not recognize commercial success and therefore it is difficult to give an accurate estimate of its speed. According to the specification it should reach up to 23.5 Mbps.

HIPERLAN / 2 is the next specification of ETSI. It continues to use the 5-GHz spectrum but with OFDM technology. Reaches up to 54 Mbps with coverage area up to 150m. HIPERLAN / 2 was designed to be used in offices, homes, high traffic 3G points.

QoS (Quality of Service) is built for multimedia communication in real time,

efficient energy consumption for mobile devices,

high security and

good interaction with Ethernet and 3G systems. This specification also allows roaming between HIPERLAN / 2 access points making it suitable for corporate environments.

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