Networking Protocols
Core Transport & Network Protocols: TCP, IP, UDP
IP (Internet Protocol)
-
Operates at the Internet/Network layer, responsible for routing packets based on source and destination IP addresses people.cs.pitt.edu+1sitepoint.com+1.
-
Two versions:
-
IPv4: 32-bit addresses (≈4.3 billion addresses).
-
IPv6: 128-bit, vastly greater capacity layerlogix.com+5itnetworkingskills.wordpress.com+5lifewire.com+5.
-
TCP (Transmission Control Protocol)
-
TCP is a connection-oriented transport layer protocol designed for reliable, ordered, error-checked delivery of data streams en.wikipedia.org+4en.wikipedia.org+4geeksforgeeks.org+4.
-
Key mechanisms:
-
Three-way handshake to establish a connection.
-
Sequencing, acks, retransmissions, congestion control.
-
-
Ideal for applications requiring data integrity: HTTP, FTP, SMTP ezexplanation.com+15geeksforgeeks.org+15en.wikipedia.org+15.
UDP (User Datagram Protocol)
-
A connectionless transport protocol with minimal overhead. No guarantee of delivery, order, or integrity sciencedirect.com+15learning.lpi.org+15reddit.com+15.
-
Fast and efficient—suitable for real-time applications like video streaming, online gaming, VoIP, and DNS reddit.com+3medium.com+3learning.lpi.org+3.
Application-Layer Protocols
These operate over TCP or UDP and provide specific user-level services:
| Protocol | Function | Transport Layer | Port(s) |
|---|---|---|---|
| DNS | Resolves domain names to IPs | UDP (or TCP) | 53 en.wikipedia.org+15student-notes.net+15thenetworkdna.com+15 |
| DHCP | Automatically assigns IP settings | UDP | 67 (server), 68 (client) |
| HTTP/HTTPS | Web content requests/responses | TCP (+TLS) | 80 / 443 |
| FTP | File transfers between client/server | TCP | 20 (data), 21 (control) |
| SMTP | Sending email between servers | TCP | 25, 465, 587 |
| POP3 | Retrieving email into clients | TCP | 110, 995 (SSL) |
| IMAP | Managing email on server | TCP | 143, 993 (SSL) |
Protocol Workflow
-
An application (e.g., browser) sends data via HTTP.
-
HTTP uses TCP for reliable transport.
-
TCP relies on IP to route packets between hosts.
-
IP packets are transmitted over the Link/Physical layer.
DNS and DHCP often use UDP to minimize delay and overhead lifewire.com+15reddit.com+15en.wikipedia.org+15en.wikipedia.org+15medium.com+15geeksforgeeks.org+15lifewire.com.
-
IP handles the delivery of packets across networks.
-
TCP ensures connections are reliable; UDP delivers faster, with fewer guarantees.
-
Application protocols (DNS, HTTP, etc.) sit on top and facilitate user-oriented services.
-
Port numbers and transport-layer behavior are crucial for interoperability.
