Ethernet Flashcards
Original designer of Ethernet
Robert Metcalfe and Xerox
Which layer is Ethernet
Layer 2 of OSI model (MAC addressing), Layer 1 OSI model (signaling)
Data encapsulation primary functions
Framing: group of bits making up a frame
Addressing
Error detection: CRC
Ethernet cables used today
UTP Copper and optical fiber
First versions of Ethernet used…
Coax cable
10BASE5
aka Thicknet; used a thick coaxial; cabling distance up to 500 m
10BASE2
aka Thinnet; smaller in diameter and more flexible than Thicknet
Hubs…
Take a group of nodes and allow the network to see them as a single unit; only one station could transmit at a time (half-duplex communication)
Switches…
only send frame only to its proper destination port (if it’s known) = full-duplex communication
Gigabit Ethernet
used to describe Ethernet implementations that provide bandwidth of 1000 Mbps (1 Gbps) or greater
Characteristic(s) of Ethernet MAC addresses
a 48-bit or 64-bit binary value expressed as 12 hexadecimal digits; use ipconfig/all
01-23-45-67-89-AB
Special value of Multicast addresses
01-00-5E
Detecting collisions on devices
all devices can detect an increase in the amplitude of the signal above the normal level causing a JAM SIGNAL
Response to JAM signal
invokes a backoff algorithm to all devices to stop transmitting for a random amount of time, allowing collisions to subside
Preamble
situation where a collision has not occurred during half duplex mode and the sending device transmits 64 bits of synchronization