WGU D315 NETWORK AND SECURITY - FOUNDATIONS
OBJECTIVE ASSESSMENT PRE STUDY 2024/2025/GRADED A+
TCP/IP
model that is a common set of protocol standards that permits the appropriate
transmission of data; used for practical application when locating specific protocol
TCP/IP layers
application, transport, network, network interface
OSI
model that enables transmission of data among hosts on a network; widely used in
network documentation and discussions
OSI layers
Application, Presentation, Session, Transport, Network, Data Link, Physical
Open Systems Interconnection (OSI)
OSI acronym
TCP and OSI
set of procedures that sends data from one host to another. Can be done over the
internet, network, or any form of communication
TCP Network Interface Layer
Physical cabling and wireless spectrum
OSI - Physical Layer
cables and connectors; establishes how a signal is transmitted via wires or airwaves;
responsible for the physical connections of the devices in a network; use hubs,
repeaters, modem devices and cabling
OSI - Data link layer
contains network card and Media Access Control (MAC) address; responsible for error-
free delivery of data to the receiving device or node; switches, bridges, or wireless/wired
network cards
Network Layer (TCP and OSI)
,Internet Protocol and Internet Control Message Protocol (ICMP); define one protocol
versus another for connecting networks
Transport Layer (TCP and OSI)
ensures data is transferred to the correct application; Transmission Control Protocol
(TCP) or User Diagram Protocol (UDP)
Transmission Control Protocol (TCP)
type of transport layer; verifies data and resends if not delivered
User Diagram Protocol (UDP)
type of transport layer; unreliable to the extent that it does not guarantee redelivery of
the data; preferred in audio streaming
TCP - Application Layer
HTTP for a web broswer; SMTP for email; DNS; Secure Shell (SSH); network time
protocol (NTP); communication protocol between nodes
OSI - Session Layer
establishes the session and ensures things are working correctly end-to-end
OSI - Presentation Layer
takes care of data encryption; translating data from the application layer into format
required to transmit data;
OSI - Application Layer
HTTP; DNS; File transfer protocol (FTP); responsible for network application; production
of data to be transferred over the network
OSI layers by number
Physical 1; Data Link 2; Network 3; Transport 4; Session 5; Presentation 6; Application
7
TCP Transport Layer
responsible for end-to-end transport data; TCP and UDP
TCP Network Layer
logical transmission protocols for the whole network; IP, Internet Control Message
Protocol (ICMP), address resolution protocol (ARP)
TCP Network Interface Layer
establishes how the data should be physically sent through the network
, OSI - Network Layer
responsible for the transmission of data between hosts in different networks as well as
routing data packets; use routers and some switches
OSI - Transport Layer
receives services from network layer and provides services to the application layer;
responsible for reliable delivery of data; segments and reassembles data in the correct
order for it to be sent to the receiving device; handle reliable delivery of data that are
lost or corrupted (TCP does this); heart of OSI
Switch
found with OSI data link; standalone or integrated with other devices; keeps traffic
between the source and destination ports from interfering with other devices on the
network;
Router
found with OSI network layer; connect home network to the internet; connect web
server to database server;
Firewalls
found in OSI layers data link, network, transport, session, and application; defines what
traffic should go between two networks; can be software that runs in virtual machine or
physical server like hardware
Firewall Layer 4
operates the network and transport layers;
Firewall Layer 7
operates at session, presentation, and application layers; decrypt and analyze the
content flowing through
Modem
A device necessary for sending and receiving data. Allows computers to transport digital
information over analog lines, such as phone or cable lines; DSL or satelite; found in
data link and physical
Repeater
OBJECTIVE ASSESSMENT PRE STUDY 2024/2025/GRADED A+
TCP/IP
model that is a common set of protocol standards that permits the appropriate
transmission of data; used for practical application when locating specific protocol
TCP/IP layers
application, transport, network, network interface
OSI
model that enables transmission of data among hosts on a network; widely used in
network documentation and discussions
OSI layers
Application, Presentation, Session, Transport, Network, Data Link, Physical
Open Systems Interconnection (OSI)
OSI acronym
TCP and OSI
set of procedures that sends data from one host to another. Can be done over the
internet, network, or any form of communication
TCP Network Interface Layer
Physical cabling and wireless spectrum
OSI - Physical Layer
cables and connectors; establishes how a signal is transmitted via wires or airwaves;
responsible for the physical connections of the devices in a network; use hubs,
repeaters, modem devices and cabling
OSI - Data link layer
contains network card and Media Access Control (MAC) address; responsible for error-
free delivery of data to the receiving device or node; switches, bridges, or wireless/wired
network cards
Network Layer (TCP and OSI)
,Internet Protocol and Internet Control Message Protocol (ICMP); define one protocol
versus another for connecting networks
Transport Layer (TCP and OSI)
ensures data is transferred to the correct application; Transmission Control Protocol
(TCP) or User Diagram Protocol (UDP)
Transmission Control Protocol (TCP)
type of transport layer; verifies data and resends if not delivered
User Diagram Protocol (UDP)
type of transport layer; unreliable to the extent that it does not guarantee redelivery of
the data; preferred in audio streaming
TCP - Application Layer
HTTP for a web broswer; SMTP for email; DNS; Secure Shell (SSH); network time
protocol (NTP); communication protocol between nodes
OSI - Session Layer
establishes the session and ensures things are working correctly end-to-end
OSI - Presentation Layer
takes care of data encryption; translating data from the application layer into format
required to transmit data;
OSI - Application Layer
HTTP; DNS; File transfer protocol (FTP); responsible for network application; production
of data to be transferred over the network
OSI layers by number
Physical 1; Data Link 2; Network 3; Transport 4; Session 5; Presentation 6; Application
7
TCP Transport Layer
responsible for end-to-end transport data; TCP and UDP
TCP Network Layer
logical transmission protocols for the whole network; IP, Internet Control Message
Protocol (ICMP), address resolution protocol (ARP)
TCP Network Interface Layer
establishes how the data should be physically sent through the network
, OSI - Network Layer
responsible for the transmission of data between hosts in different networks as well as
routing data packets; use routers and some switches
OSI - Transport Layer
receives services from network layer and provides services to the application layer;
responsible for reliable delivery of data; segments and reassembles data in the correct
order for it to be sent to the receiving device; handle reliable delivery of data that are
lost or corrupted (TCP does this); heart of OSI
Switch
found with OSI data link; standalone or integrated with other devices; keeps traffic
between the source and destination ports from interfering with other devices on the
network;
Router
found with OSI network layer; connect home network to the internet; connect web
server to database server;
Firewalls
found in OSI layers data link, network, transport, session, and application; defines what
traffic should go between two networks; can be software that runs in virtual machine or
physical server like hardware
Firewall Layer 4
operates the network and transport layers;
Firewall Layer 7
operates at session, presentation, and application layers; decrypt and analyze the
content flowing through
Modem
A device necessary for sending and receiving data. Allows computers to transport digital
information over analog lines, such as phone or cable lines; DSL or satelite; found in
data link and physical
Repeater
