TCP

Abstract

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• The Stateful Network Protocol used transfer data from one Computer Network to another
• Implemented inside the Kernel

Guaranteed Delivery

Server will keep sending to Client until an Acknowledgment is received

Require more bandwidth

Compared to UDP, TCP has more features which result in larger packet, thus consuming more bandwidth when transferring the same amount of data

Vulnerable to DDoS

TCP is a stateful network protocol, Main Memory is consumed to store the state of each TCP Connection and CPU is also involved

Slower than UDP

The extra features TCP offers incur extra time to execute

Communication is easy to break

Both Host need to keep track the information of TCP Connection. When one party is down, the another party will get notified and the TCP Connection will be shut down automatically. This means we need to reinitialised another TCP connection again

Hard to customise

Kernel handles the implementation of TCP. If we want some custom features for TCP, we need to modify the kernel codes

Get your hands dirty

Create a TCP Server on port 8080

• socat - TCP-LISTEN:8080,fork spins up a TCP server that creates a new Process (进程) for each new TCP Connection

Create a TCP Client

• telnet 127.0.0.1 8080 (intall on mac brew install telnet) connects to localhost:8080 over TCP. A new socat process should be created

Create TCP Server in NodeJS

• Refer to TCP Server written in NodeJS

TCP Slow Start

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• Only a small amount of data is transferred to test the water at the start of the communication. If data is delivered smoothly, TCP will gradually increase the amount of data

Avoid network congestion

If a particular network path is congested and we dump a lot of data to the data. The congested network path will result in a lot of packet loss, and this incurs extra time to resend the network packets

Initial lag

A slower startup speed means accessing new resources like a new web page will appear laggy