Ethernet Basics

Question 1

Ethernet IEEE standard, which became open-source at the time of transferal

Answer 1

IEEE 802.3

Question 2

7-byte alternating ones and zeros that precede a frame, added by the sending NIC

Answer 2

preamble

Question 3

1-byte positioned after the preamble that precedes a frame

Answer 3

start frame delimiter

Question 4

the result of a cyclic redundancy check place at the end of frame in order to detect if a frame was received undamaged; the receiving NIC performs the same check on the data and compares its results to this

Answer 4

frame check sequence (FCS)

Question 5

a special mathematical function performed on the data in a frame at both the receiving and sending in; used to detect damaged frames/data

Answer 5

cyclic redundancy check (CRC)

Question 6

signaling type for networking - cable carries multiple channels or signals; used with cable TV, cable Internet

Answer 6

broadband

Question 7

system in which computers/nodes examines a shared cable to see if it detects traffic before sending a frame; all nodes have equal access to the shared cable

Answer 7

carrier sense multiple access/collision detection (CSMA/CD)

Question 8

group of nodes that have the capability of sending frames at the same time

Answer 8

collision domain

Question 9

device that acts like a repeater in order to connect two networks; it it filtered forwarded traffic based on MAC addresses between the two segments and preserved bandwidth

Answer 9

bridge

Question 10

device used to interconnect nodes in a network by creating point-to-point connections using a table of MAC addresses; each port is its own collision domain, and incoming frames can be buffered to prevent collision

Answer 10

switch

Question 11

the table of MAC addresses stored inside of the switch; it copies the source MAC addresses of incoming frames to fill in the table

Answer 11

source address table (SAT)

Question 12

ports on older switches used to interconnect multiple switches; one would plug one end of a straight-through cable into this port and then plug the other end into any regular port on another switch

Answer 12

uplink port (switch)

Question 13

IEEE 802.1d, protocol enabled by default in switches to detect and mitigate any potential bridging loop using bridge protocol data units

Answer 13

spanning tree protocol (STP)

Question 14

frame in a switch used to establish a topology, with one switch acting as the center switch; any potential bridging loop is avoided by blocking a port from receiving traffic except for these

Answer 14

configuration bridge protocol data units (BPDUs)

Question 15

frame in a switch that activates when a failed device or interface occurs, causing blocked ports to function in a forwarding state to work around the failed device or interface

Answer 15

topology change notification (TCN) BPDU

Question 16

setting in a switch for a port connected to a PC; allows the interface to come up right away without the normal STP latency and prevents BPDUs from being sent out the port every time a PC turns on or off (possibly causing switches to flush their source address tables)

Answer 16

PortFast

Question 17

setting/flag in a switch that transfers a port configured with PortFast to an errdisable state if it receives a BPDU; usually requires an admin to enable it again

Answer 17

BPDU Guard

Question 18

mechanism in a switch that transfers a port to a root-inconsistent state if received BPDUs indicate another switch is trying to become the root bridge; automatically changes back when frames stop

Answer 18

root guard

Question 19

IEEE 802.w, protocol that replaced STP with faster convergence time after a network change

Answer 19

Rapid Spanning Tree Protocol (RSTP)