Bits & Bytes: Week 1, V - the Data Link Layer Flashcards
What is the most type of network used in the workplace and data centers?
Ethernet
ACRONYM:
CSMA/CD
Carrier Sense Multiple Access with Collision Detection
acronym
A technique used to determine when communications channels are clear, and a device is free to transmit data
Carrier Sense Multiple Access with Collision Detection
definition
A network segment where all devices receive all communication across the entire segment.
A collision domain
A 48-bit number normally represented by six groupings of two hexadecimal numbers
A MAC Address
A way to represent numbers using 16 digits
Hexadecimal
What is 10 in hexadecimal numbers?
A
What is 11 in hexadecimal numbers?
B
What are 12 and 15 in hexadecimal numbers?
C and F, respectively
What are 13 and 14 in hexadecimal numbers?
D and E, respectively
What is a computer networking term for any number that can be represented by 8 bits?
An Octet
ACRONYM:
OUI
Organizationally Unique Identifier
What do the first 3 octets of a MAC address represent?
They are assigned to individual hardware manufacturers.
This means that you can identify who makes a device using just its MAC number.
ACRONYM:
IEEE
Institute of Electrical and Electronics Engineers
__________ uses __________ addresses to ensure that the data it sends has an address for both the sending and receiving devices of a transmission.
Ethernet; MAC
When one device transmits data to exactly one other device
A Unicast Transmission
When one device transmits to all devices on a local network signal
A Multicast Transmission
When one device sends data to all devices on a LAN
A Broadcast Transmission
What is the Ethernet broadcast address?
FF:FF:FF:FF:FF:FF
What is the term for an Ethernet Data Packet?
Ethernet Frame
A highly structured collection of information presented in a specific order in Ethernet protocol
Definition of an Ethernet Frame
The first part of an Ethernet frame
Preamble
How long is a preamble?
8 bytes (64 bits)
ACRONYM:
SFD
Start Frame Delimiter
acronym
What is the term for the last byte of the preamble of an ethernet frame?
Start Frame Delimiter
location and size
What signals to a receiving device that the preamble is over and that the actual frame contents will now follow?
Start Frame Delimiter
purpose
What part of the Ethernet frame follows the Start Frame Delimiter?
the Destination Address
location in an ethernet frame
What part of the Ethernet frame follows the Destination Address?
The Source Address
location in an ethernet frame
What part of the Ethernet frame often follows the Source address?
The VLAN Header
location in an ethernet frame
What part of the Ethernet frame follows the VLAN header, if present, or the Source Address, if no VLAN header?
The EtherType Field
location in an ethernet frame
ACRONYM:
VLAN
Virtual Local Area Network
acronym
This technique allows multiple logical LANS to operate on the same physical equipment.
VLAN; or Virtual Local Area Network
use of
What part of the Ethernet frame follows the EtherType Field?
The Payload
location in an ethernet frame
The data intended to be transmitted via the Ethernet Frame
The Payload
definition
How large is the data payload of a traditional ethernet frame?
46 to 1500 bytes
size of ethernet payload
What part if the Ethernet Frame follows the Payload?
The Frame Check Sequence
location in Ethernet frame
ACRONYM:
FCS
Frame Check Sequence
acronym
A 4-byte number that represents a checksum value for the entire Ethernet frame
Frame Check Sequence
definition
ACRONYM:
CRC
Cyclical Redundancy Check
acronym
This number, derived via a Cyclical Redundancy check, should match when calculated before data is sent and when calculated when data is received.
Checksum Value
use
A calculation used to find the Checksum Value
Cyclical Redundancy Check
definition
What does it mean when the Frame Check Sequence doesn’t match the number generated using the Cyclical Redundancy Check upon receipt of the message?
The data has been corrupted during transmission process.
What happens to data that fails the Cyclical Redundancy Check?
It’s discarded
