Function
What is the function of the Application Layer?
Connects users and apps (services)
What are some of the primary protocols at the Application Layer along with their common associated ports?
HTTP (80)
HTTPS (443)
SSH (22)
DNS (53)
DHCP (67/68)
What is the data unit for the Application Layer?
Data or Messages
What is used for addressing at the Application Layer?
Trick question! The Application Layer doesn't do any addressing.
What is a command you can use at the Application Layer for querying the Domain Name System to obtain domain name or IP address mapping?
nslookup
What is the function of the Transport Layer?
Connects processes from one host to another host (reliability)
What are the two main protocols at the Transport Layer?
Transmission Control Protocol (TCP), User Datagram Protocol (UDP)
What are the data units at the Transport Layer?
Segments (for TCP), Datagrams (for UDP)
What is used for addressing at the Transport Layer?
Port Number
What is a command you can use at the Transport Layer for network statistics?
netstat
What is the function of the Network Layer?
Connects networks; routes traffic across Internet
What are the two main protocols at the Network Layer?
Internet Protocol (IP), Internet Control Messaging Protocl (ICMP)
What is the data unit at the Network Layer?
Packets
What is used for addressing at the Network Layer?
IPv4 or IPv6
What is the primary piece of hardware that operates at the Network Layer
Router
What is the function of the Data Link Layer?
Connects hosts on the same local area network
What are some protocols at the Data Link Layer?
Ethernet (IEEE 802.3), WiFi (IEEE 802.11), LTE/5G
What is the data unit at the Data Link Layer?
Frames
What is used for addressing at the Data Link Layer?
Media Access Control (MAC) Address
What is the primary piece of hardware that operates at the Data Link Layer?
Switch
What is the function of the Physical Layer?
Connects two devices
How is information represented at the Physical Layer?
Voltages, RF Signals
What is the data unit at the Physical Layer?
Bits or Bytes
What is used for addressing at the Physical Layer?
Trick question! The Physical Layer does not do any addressing.
What is the primary piece of hardware that operates at the Physical Layer?
Hub