Networking
Computer networks communicate with each other with protocols. The OSI model has 7 layers, the TCP/IP model has 4. This table summarizes the layers and the protocols of the TCP/IP model:
| Layer | Function | Example Protocols |
|---|---|---|
| Application | User services & data formats, how apps communicate with each other | HTTP, FTP, DNS, SMTP |
| Transport | Host-to-host communication, how datagrams are received (socket programming) | TCP, UDP |
| Internet | Routing and addressing, how bits and bytes are organized into datagrams | IP, ICMP, IGMP |
| Link | Physical network access | Ethernet, Wi-Fi, ARP |
Terminology
- backpressure
- When an upstream component has to reduce its data transmission rate when a downstream component is overwhelmed. For example, a TCP network logger has to reduce its writes over the network because the log server’s buffer is full and cannot process all logging requests in time.
- throughput
- The actual rate that data successfully transmits over a network from sender to receiver over a period of time.