TECH-Tips Week of 9-25 - Fieldbus Encapsulation - LEDs/Lasers-Transparent LAN Switches-RF Azimuth-Earth Buldge - MIM Poison Attacks

TECH-Tips Week of 9-25 - Fieldbus Encapsulation - LEDs/Lasers-Transparent LAN Switches-RF Azimuth-Earth Buldge - MIM Poison Attacks. Check it out:
TECHtionary TECH-Tips Week of September 25-29, 2006

Monday Fieldbus Encapsulation
Tuesday - LEDs versus Laser Diodes
Wednesday Transparent LAN Switches
Thursday RF Azimuth & Earth Bulge
Friday Man-in-the-Middle Poison Attacks

The animated tutorials are available at: http://www.techtionary.com
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Monday TECHtionary.com TECH-Tip Fieldbus Encapsulation
Here is the encapsulation process for Fieldbus. This is an example
of how protocols at different layers are used to provide data
communications. Fieldbus is a standard data communications protocol
using in ERP-Enterprise Resource Planning (manufacturing) and other
industrial applications. While Fieldbus can work with Ethernet,
Fieldbus has its own data protocol format (shown here) or use a
number of OSI Layers to provide for data communications.
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Tuesday TECHtionary.com TECH-Tip LEDs versus Laser Diodes
A few words on Light Sources The advantages of LED-Light Emitting
Diodes are: - Lower power - High spectral spread - Non-coherent
(LASER) light - Wide differential group delay (see Next)
The advantages of LD-Laser Diodes are:
- High power - Single wavelength frequency - Coherent LASER light -
Narrow modal dispersion LASER-Light Amplified Stimulated Emitted
Radiation

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Wednesday TECHtionary.com TECH-Tip Transparent LAN Switches
Transparent LAN Switches build Tables/Lists based on MAC-Media Access
Control (LAN card address) and then forward packet out port
associated with the MAC address unless address is unknown or
broadcast and then flood to all ports.
LAN switches and bridges are Layer 2-Datalink devices do NOT filter
broadcast traffic. That is, switches and bridges do NOT change the
broadcast domain (area of service). In other words, if the
switch/bridge does not know the MAC addresses, they will
flood/forward frames to ANYWHERE they don't know the MAC address. A
large number of flooded frames causes slow performance and is called
a Broadcast Storm in a broadcast domain. However, bridges/switches
can reduce the number of collisions without changing the broadcast
domain.
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Thursday TECHtionary.com TECH-Tip Azimuth & Earth Bulge
Azimuth refers to the angle of direction such as east is 90 degrees,
south is 180, degrees west is 270 degrees and north 360 or 00.
Degrees. Altitude refers to position relative to the horizon at 00
degrees with +90 degrees straight up and -90 degrees straight down.
Since we are talking about the earth issues, Earth Bulge is the
natural angle of the earth over distance. That is, antenna height
must be adjusted when towers are separated by more than seven miles.
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Friday TECHtionary.com TECH-Tip Man-in-the-Middle Poison Attacks
In a wireless network, Hackers can use ARP to mislead or poison other
hosts. Hacker Host C is now the "Man-in-The Middle" and can monitor
telnet (terminal emulation) sessions, intercept and read SMTP-Simple
Mail Transfer Protocol or POP-Post Office Protocol email, SSH-Secure
SHell encrypted data host-server transactions or upload viruses to
any or all hosts. Here are four scenarios which poison attacks may
likely occur.
Scenario 1 - Hacker attacks two or more wired hosts on the same AP-
Access Point and same LAN switch.
Scenario 2 - Hacker attacks two or more wired and wireless hosts on
the same AP-Access Point and same LAN switch.
Scenario 3 - Hacker attacks two wireless hosts on the same AP-Access
Point and same LAN switch.
Scenario 4- Hacker attacks two or more wireless hosts on multiple AP-
Access Points and multiple LAN switches.

ABOUT
TECHtionary.com produces dealer and customer training programs, online presentations including iPod and PC formats sales brochures, virtual installation manuals and animated online presentations. The company has more than 2,850+ free online presentations on data communications,, internet, wireless, VoIP-Voice over Internet Protocol, PBX Systems, central office switching, protocols, telephony, telecommunications, networking, routing, IPTV, WiMax, power systems, broadband, WiFi-wireless fidelity and other related technologies available at http://www.techtionary.com. TECHtionary also produces VoIP Dealer Training. Some of the key highlights are: Building a VoIP Business, Selling & Marketing VoIP, Customer and End User Training, VoIP Technology, Network Design, Provisioning, Customer Service, Dealer Portal, and Enhanced & Professional Services. VoIP training is also available as a one-day introduction to a five-day indepth course and can be customized and delivered via web seminar or online tutorial series. More details on VoIP Dealer training are available by calling Tom Cross at 303-594-1694 or [email protected] Thomas Cross is a magazine columnist with many key technology publications and a member of the Technical Board of Advisors for the VoIP-Security Alliance.

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