3.2 Connections (Ethernet shared media and point-to-point)
Computers connected by communication channels that each connect Exactly two computers with access to full channel bandwidth.
Forms a mesh or point-to-point network.
Allows flexibility in communication hardware, packet formats, etc.
Provides security and privacy because communication channel is not shared.
Number of channels grows as square of number of computers
Shared or Broadcast Channel:
All computers connected to a shared broadcast-based communication channel and share the channel bandwidth.
Security issues as a result of broadcasting to all computers.
Cost effective due to reduced number of channels and interface hardware components.
Ethernet: Ethernet is the most widely used LAN technology. Invented at Xerox PARC (Palo Alto Research Center) in 1970s. Defined in a standard by Xerox, Intel and Digital - DIX standard. Standard is now managed by IEEE - defines formats, voltages, cable lengths, etc., IEEE 802.3:
10BASE-T: Standard Ethernet 10Mbps.
100-BASE-T: Fast Ethernet 100Mbps.
1000-BASE-T: Gigabit Ethernet 1000Mbps.
One Ethernet cable is sometimes called a segment.
Limited to 500 meters in length for 10BASE-T.
Bus Topology: Single coax, cable forming a segment - the ether
Star Topology: Using hubs or switches (several segments).