OSI Middle Layers Flashcards
What are the 7 main layers of the OSI model?
7 Application, 6 Presentation, 5 Session, 4 Transport, 3 Network, 2 Data Link, 1 Physical
What is the function of the Transport Layer?
Segmentation, transfer and reassemble, uses ports and sockets
What are the two main protocols of the Transport Layer?
TCP (Transmission Control Protocol), UDP (User Datagram Protocol)
How does TCP ensure reliable delivery?
Uses acknowledged delivery and other processes to ensure delivery
What is a disadvantage of using TCP?
Makes larger demands on the network – more overhead
What does UDP provide?
Just the basic functions for delivery – no reliability
What are the four basic processes of the Transport Layer?
- Message Segmentation
- Transfer & Reassemble
- Error Control
- Port Numbers
What is Message Segmentation?
Divides data from the application layer into smaller parts
What is the purpose of a port number?
A unique identifier assigned to network protocols to facilitate communication
Fill in the blank: Port 80 is the default port for _______.
Hypertext Transfer Protocol (HTTP)
Fill in the blank: Port 443 is used for _______.
Hypertext Transfer Protocol Secure (HTTPS)
What is a socket in networking?
Combination of the source and destination IP addresses and the source and destination port numbers
What is the role of the router in the Network Layer?
Select paths for and direct packets toward the destination host
What is Open Shortest Path First (OSPF)?
A link-state routing protocol that calculates the shortest path between routers using the Dijkstra algorithm
What are the two parts of an IP address?
- Network prefix
- Host part
What is the difference between public and private IP addresses?
- Public IP: Assigned to a device connected to the internet
- Private IP: Used within a private network
What is the difference between static and dynamic IP addresses?
- Static IP: Remains the same over time
- Dynamic IP: Assigned dynamically and can change
What are the two main versions of IP addresses?
- IPv4
- IPv6
Fill in the blank: An IPv4 address has _______ bits.
32
Fill in the blank: An IPv6 address has _______ bits.
128
What is a subnet mask?
A 32-bit number used to separate IP addresses into network and host portions
What is the purpose of subnetting?
Enables efficient use of IP addresses and enhances network security
What is error control in the Transport Layer?
Techniques such as acknowledgment, sequencing, and retransmission to detect and recover from transmission errors
