TCP/IP Detailed Volume one (19th. TCP Interactive data stream)

TCP needs to process two types of data at the same time: block data, interactive data.

This chapter will take the Rlogin application as an example to observe the transfer process of interactive data.

Interactive input

First, the flow of data generated by typing an interactive command on a rlogin connection (each typing an interactive key produces a data grouping), which results in 4 segments:

1. Interactive keys from the customer;

2. Key confirmation from the server;

3. Key echo from the server;

4. The key echo confirmation from the customer.

However, we can generally combine the message segment 2 with the message segment 3.

Is the tcpdump output when you type data\n (plus carriage return) in a rlogin connection

Confirmation of the time delay

Typically, TCP does not immediately send an ACK when it receives data, and it defers sending to send the ACK along with the data that needs to be sent in that direction.

Most implementations use a delay of 200ms, which means that TCP will wait for data to be sent with a maximum of 200ms latency.

TCP/IP Detailed Volume one (19th. TCP Interactive data stream)