100% Solved
Transmission Media Ethernet supports the following cable types:
• Unshielded twisted pair (UTP) cables with RJ45 connectors. This is the most common
transmission medium used for Ethernet.
• Fiber optic cables, most commonly used in high-speed applications, such as servers or
streaming media.
• Coaxial cables for older Ethernet implementations (often called thinnet or thicknet networks).
Media Access Method Ethernet uses a contention-based media access method defined by
the IEEE 802.3 standards called Carrier Sense, Multiple Access/Collision Detection
(CSMA/CD). Devices use the following process to send data:
• Because all devices have equal access (multiple access) to the transmission media, a device
listens to the transmission medium to determine if it is free before sending data (carrier sense).
• If it is not free, the device waits a random amount of time and listens again to the transmission
medium. If it is free, the device transmits its message.
• If two devices transmit at the same time, a collision occurs. The sending devices detect the
collision (collision detection) and send a jam signal to notify all other hosts that a collision has
occurred.
• Both devices wait a random length of time before attempting to resend the original message
(backoff).
, TestOut Networking Pro Ch 4 With Solutions
100% Solved
Devices with collision detection turned on operate in half-duplex mode; devices with collision
detection turned off operate in full-duplex mode
Half Duplex • Collision detection is turned on.
• The device can send or receive in only one direction at a time.
• Devices connected to a hub must use half-duplex communication.
Up to the rated bandwidth (10 Mbps for 10BaseT, 100 Mbps for 100BaseT, etc.)
Full Duplex • Collision detection is turned off.
• The device can send and receive at the same time.
• Requires full-duplex capable NICs.
• Requires switches with dedicated switch ports (a single device per port).
Double the rated bandwidth (20 Mbps for 10BaseT, 200 Mbps for 100BaseT, etc.)
Physical Addresses Ethernet devices are identified by using the MAC address, which is
burned into the network interface card.