TCP/IP Networking
WHAT IS TCP/IP?
Transmission Control Protocol/Internet Protocol (TCP/IP) is a set of networking protocols used to connect all types of computing devices to each other, from local area networks to the Internet. TCP/IP-based networks are used in home offices, small offices, large business offices, enterprises, and the world’s largest network, the Internet.
TCP VS. UDP
There are two main protocols used to move data around on TCP/IP networks: TCP and UDP. These two protocols are the workhorses of modern networks, moving data between systems. Almost every time that data is sent over the Internet or a local network, it is sent using either TCP or UDP. You need to understand the differences between the two.
TCP is a connection-oriented
protocol. When TCP protocol is used to transmit data, the sender must receive a response from the receiver that the information was received. If the response is missing or the receiver indicates that the information isn’t correct, the sender transmits the information again. TCP is like making a phone call; the call is not a success if the call isn’t picked up.
UDP is a connectionless protocol.
When UDP is used to transmit data, the data is sent, but there is no checking to make sure the data was received. UDP is like sending an SMS text message; there’s no way to know if it arrived if the receiver doesn’t reply.
Each of these approaches has their place on modern networks. Connection-oriented protocols provide guaranteed delivery of data but require extra work by networked devices, so they move a little more slowly. Connectionless protocols do move faster, but they don’t provide
that guaranteed delivery.
HTTPS and SSH.
HTTPS stand for Hypertext Transfer Protocol Secure (HTTPS) is the secure version of the HTTP protocol used by web browsers to request and receive web pages. Today, almost every website uses HTTPS instead of HTTP to provide secure, encrypted connections that are safe from
eavesdropping.
When a device requests a web page using HTTPS, it must receive an acknowledgment that the website is secure before the connection can continue.
SSH
Secure Shell (SSH) provides for secure login to servers and other types of remote services.
SSH uses encryption to create a secure connection after a user provides standard login information during the first login. The SSH information is stored in the connecting device and is used automatically thereafter.
Connectionless
While some protocols depend upon the guaranteed delivery of a connection-oriented protocol like TCP, other applications do not need this high level of service and can instead use the connectionless delivery offered by UDP. In cases where application protocols use UDP, they must be able to tolerate missing data either by retrying transmissions until they receive a response or by simply ignoring missing data.
There are many different UDP protocols. Let’s take a closer look at a couple to understand how they work.
DHCP
Dynamic Host Configuration Protocol (DHCP) is a protocol that assigns Internet Protocol (IP) addresses on demand to connected devices. IP places data into packets, adds source and destination information, and delivers network packets based on the IP addresses stored in data packets.
When a device connects to a TCP/IP network that uses DHCP, the DHCP server checks its list of available IP addresses and provides one for the device to use.
Trivial File Transfer Protocol
Trivial File Transfer Protocol (TFTP) is a stripped-down version of File Transfer Protocol (FTP).
It is used for the BOOTP bootstrap protocol for diskless workstations, for upgrading firmware in home network routers, and for software distribution on corporate local area networks.
It uses UDP for file transfer.
