Protocol
a defined set of standards that computers must follow in order to communicate properly
Computer Networking
The communication of information or services between computers using wireless or cable transmission media
Physical Layer
layer representing the physical devices that interconnect computers;
includes but is not limited to cables, jacks, patch panels, punch blocks, hubs, and MAUs.
Data Link Layer
layer responsible for defining a common way of interpreting these signals so network devices can communicate;
moves messages from one device to another
Network Layer
layer that allows different networks to communicate with each other through devices known as routers;
responsible for routing messages from one node to another
Internetwork
A collection of networks connected together through routers
Internet Protocol (IP)
a set of rules responsible for disassembling, delivering, and reassembling packets over the internet
Transport Layer
layer that sorts out which client and server programs are supposed to get what data;
ensures accurate delivery of data; solves transmission problems; provides error-free reassembly
Transmission Control Protocol (TCP)
provides reliable, ordered and error checked delivery of a stream of packets in the internet
User Datagram Protocol (UDP)
alternative communications protocol used primarily for establishing low-latency and loss tolerating connections between apps on the internet
Application Layer
layer that includes the software that we use, the part of the model that is closest to the user (gmail, browser, etc.)
cables
connect different devices to each other, allowing data to be transmitted across them
crosstalk
when an electrical pulse on one wire is accidentally detected on another wire - leads to data error
copper cable
cables made of insulated copper that uses electrical pulses to transmit data
fiber cable
contain individual optical fibers (tiny tubes made out of glass) that uses light to transmit data.
faster/longer data transmission but more expensive than copper
network hub
A hardware device that can have a number of devices/computers connected to it and each other.
data is transmitted to all connected devices
collision domain
network segment where data packets may collide with one another when being sent
network switch
a hardware device that can connect multiple nodes to each other;
can detect and route data to its intended destination (not everywhere)
Hubs/Switches
primary devices used to connect computers on a single local area network (LAN)
Network Router
A device that forwards data packets between computer networks
Border Gateway Protocol
protocol where routers share data with each other, allowing them to determine the most optimal path to forward traffic
Bit
The smallest representation of data that a computer can understand (1 or 0)
Modulation
a way of varying the voltage of a charge moving across a cable. This method is used to send bits across the network
Line Coding
a form of modulation specific to networking, that allows devices on either end of a link to understand the electrical charge states of 1 & 0
Duplex communication
The concept that information can flow in both directions across the cable
Simplex communication
unidirectional; information only flows in one direction
Full-Duplex communication
Information can flow both directions at the same time
Network Ports
ports attached to devices that make up a computer network. Allows attachment of network cables (RJ-45 cables)
Patch Panel
device that contains many network ports; used as a container for the endpoints of cables. Usually "patches" into switches/routers
Carrier Sense Multiple Access w/ Collision Detection (CSMA/CD)
protocol used to determine when communication lines are clear and when a device is free to transmit
MAC (Media Access Control) address
globally unique identifier attached to an individual network interface. 48-bit # represented by 6 groups of 2 hex #'s
Hexadecimal
a representation of numbers using 16 digits
Organizationally Unique Identifier (OUI)
1st 3 octets of a MAC address, used to uniquely identify a vendor, manufacturer, or organization
Unicast
transmission method where information is sent from one point to another
Multicast
transmission method where information is sent from one point to many "selected" receivers
Broadcast
transmission method where information is sent to all recipients
Data Packet
any single set of binary data being sent across a network link
Ethernet Frames
highly structured collection of information presented in a specific order
Preamble
1st part of an ethernet frame; acts as a buffer between frames and can be used by the network to regulate the speed at which the frame is sent
Start Frame Delimiter (SFD)
last byte of the preamble used to signal the receiving device that the preamble is over and the actual frame will follow
Destination address
hardware address of the intended recipient
Source Address
the hardware address of the sender
Ether-type Field
describes the protocol of the contents of the frame
VLAN
technique allowing multiple logical LANS operating on the same physical equipment
Payload
actual data being transported (anything not the header)
Frame Check Sequence (FCS)
represents a checksum value for the entire frame. Uses CRC code to check for errors w/in the frame
Protocol
a defined set of standards that computers must follow in order to communicate properly
Computer Networking
The communication of information or services between computers using wireless or cable transmission media
Physical Layer
layer representing the physical devices that interconnect computers;
includes but is not limited to cables, jacks, patch panels, punch blocks, hubs, and MAUs.
Data Link Layer
layer responsible for defining a common way of interpreting these signals so network devices can communicate;
moves messages from one device to another
Network Layer
layer that allows different networks to communicate with each other through devices known as routers;
responsible for routing messages from one node to another
Internetwork
A collection of networks connected together through routers
Internet Protocol (IP)
a set of rules responsible for disassembling, delivering, and reassembling packets over the internet
Transport Layer
layer that sorts out which client and server programs are supposed to get what data;
ensures accurate delivery of data; solves transmission problems; provides error-free reassembly
Transmission Control Protocol (TCP)
provides reliable, ordered and error checked delivery of a stream of packets in the internet
User Datagram Protocol (UDP)
alternative communications protocol used primarily for establishing low-latency and loss tolerating connections between apps on the internet
Application Layer
layer that includes the software that we use, the part of the model that is closest to the user (gmail, browser, etc.)
cables
connect different devices to each other, allowing data to be transmitted across them
crosstalk
when an electrical pulse on one wire is accidentally detected on another wire - leads to data error
copper cable
cables made of insulated copper that uses electrical pulses to transmit data
fiber cable
contain individual optical fibers (tiny tubes made out of glass) that uses light to transmit data.
faster/longer data transmission but more expensive than copper
network hub
A hardware device that can have a number of devices/computers connected to it and each other.
data is transmitted to all connected devices
collision domain
network segment where data packets may collide with one another when being sent
network switch
a hardware device that can connect multiple nodes to each other;
can detect and route data to its intended destination (not everywhere)
Hubs/Switches
primary devices used to connect computers on a single local area network (LAN)
Network Router
A device that forwards data packets between computer networks
Border Gateway Protocol
protocol where routers share data with each other, allowing them to determine the most optimal path to forward traffic
Bit
The smallest representation of data that a computer can understand (1 or 0)
Modulation
a way of varying the voltage of a charge moving across a cable. This method is used to send bits across the network
Line Coding
a form of modulation specific to networking, that allows devices on either end of a link to understand the electrical charge states of 1 & 0
Duplex communication
The concept that information can flow in both directions across the cable
Simplex communication
unidirectional; information only flows in one direction
Full-Duplex communication
Information can flow both directions at the same time
Network Ports
ports attached to devices that make up a computer network. Allows attachment of network cables (RJ-45 cables)
Patch Panel
device that contains many network ports; used as a container for the endpoints of cables. Usually "patches" into switches/routers
Carrier Sense Multiple Access w/ Collision Detection (CSMA/CD)
protocol used to determine when communication lines are clear and when a device is free to transmit
MAC (Media Access Control) address
globally unique identifier attached to an individual network interface. 48-bit # represented by 6 groups of 2 hex #'s
Hexadecimal
a representation of numbers using 16 digits
Organizationally Unique Identifier (OUI)
1st 3 octets of a MAC address, used to uniquely identify a vendor, manufacturer, or organization
Unicast
transmission method where information is sent from one point to another
Multicast
transmission method where information is sent from one point to many "selected" receivers
Broadcast
transmission method where information is sent to all recipients
Data Packet
any single set of binary data being sent across a network link
Ethernet Frames
highly structured collection of information presented in a specific order
Preamble
1st part of an ethernet frame; acts as a buffer between frames and can be used by the network to regulate the speed at which the frame is sent
Start Frame Delimiter (SFD)
last byte of the preamble used to signal the receiving device that the preamble is over and the actual frame will follow
Destination address
hardware address of the intended recipient
Source Address
the hardware address of the sender
Ether-type Field
describes the protocol of the contents of the frame
VLAN
technique allowing multiple logical LANS operating on the same physical equipment
Payload
actual data being transported (anything not the header)
Frame Check Sequence (FCS)
represents a checksum value for the entire frame. Uses CRC code to check for errors w/in the frame