June 16, 2012

1.6.12 Power Level Controls

Power level controls

Some access points (AP) include power level controls that allow you to adjust the amount of output provided.

Antenna power level controls are typically set by the manufacturer to a level suitable for an average environment. However this power level can be changed as informed by a site survey and antenna placement adjustments. The power level can be increased to strength the signal or it can be decreased for example to keep wireless signals from leaking outside the coverage area.

1.6.11 Antenna Placement

Antenna Placement

The performance of a wireless network greatly depends on signal strength of the wireless access point (AP) and the location of the wireless clients. Antenna placement can be crucial in allowing signals from the AP to reach the clients. This signal can be affected by the construction materials of walls, the network range, and the strength, sensitivity and quality of the antennas.

Signal strength depends on the environment in which the access point is placed. As a general rule, the greater the distance the signal travels, the more it will attenuate. Factors such as construction materials of walls, the network range, and the strength, sensitivity and quality of the antennas can further affect the signal strength.
In general, the AP should be at the center of a circle (or sphere) with a minimum radius.

Clients situated near the edge of the network range will likely experience network performance issues or dropped connections.

Avoid placing AP near objects that can absorb or reflect the signal.

References:
  • http://en.wikipedia.org/wiki/CCMP
  • alt.internet.wireless

1.6.10 CCMP

CCMP

Counter Cipher Mode with Block Chaining Message Authentication Code Protocol (CCMP) is an encryption protocol designed for Wireless LAN products that implement the full IEEE 802.11i standard (IEEE 802.11i-2004). CCMP is a data cryptographic encapsulation mechanism designed for data confidentiality and based upon the Counter Mode with CBC-MAC (CCM) of the AES standard. It was created to address the vulnerabilities presented by TKIP, a protocol in WPA, and WEP.

CCMP is an AES-based encryption mode introduced with WPA2 and it is more secure than the WEP protocol and TKIP protocol of WPA. It provides the following security services:
  • Data Confidentiality; ensures only authorized parties can access the information
  • Authentication; provides proof of genuineness of the user
  • Access control in conjunction with layer management
CCMP uses 128-bit AES encryption with a 48-bit initialization vector.

CCMP computes a Message Integrity Check (MIC) using the well known, and proven, Cipher Block Chaining Message Authentication Code (CBC-MAC) method. Changing even one bit in a message produces a totally different result.

Advanced Encryption Standard (AES) is the cipher system used by Robust Security Network (RSN). It is the equivalent of the RC4 algorithm used by WPA. CCMP is the security protocol used by AES. It is the equivalent of TKIP in WPA.

In the beginning there was WEP. It’s security protocol was weak. WPA (with TKIP) fixed some of the issues with WEP, however it was an intermediate solution, implementing a portion of the 802.11i standard. WPA2 (with CCMP) was a full implementation of the 802.11i standard.

References:
  • http://en.wikipedia.org/wiki/CCMP
  • http://www.openxtra.co.uk/articles/wpa-vs-80211i