TCP/IP

Question 1

The Link layer

Answer 1

The Link layer includes all of the complex engineering required to move data across a single “hop”, whether the hop is a wireless WiFi, wired Ethernet, fiber optic, or satellite connection.

Question 2

The Internetwork Protocol (IP) layer

Answer 2

The Internetwork Protocol (IP) layer is how data is routed across a series of hops to get quickly and efficiently from one of a billion source computers to any of a billion destination computers. The IP layer dynamically adjusts and reroutes data based on network load, link performance, or network outages. While the IP layer is highly reliable and fast, at times it loses or even throws away data. The IP layer is not responsible for ensuring the overall reliability of the network. It just moves the data the best that it can

Question 3

The Transport layer

Answer 3

The Transport layer compensates for any imperfections in the IP or Link layers. The Transport layer makes sure that any lost packets are retransmitted and packets that arrive out of order are put back into order before being passed on to the receiving application. The Transport layer also acts as flow control between the sending and receiving applications to make sure that data is moved quickly when the network is fast and the links are not overloaded, and to slow the transfer of data when using slower or heavily loaded links. The data flow and rate limitation in the Transport layer allow the Internet to continue to function smoothly even when it is heavily loaded. + encryption/decryption (Secure Sockets Layer - SSL, Transport Layer Security - TLS)

Question 4

The Application Layer

Answer 4

The other three layers make the use of the network very simple for the Application Layer. An application can make a network connection and send/receive data on that connection with just a few lines of code.