Linux Network Application Programming Hub (Packet Tracer simulation), packettracer

Linux Network Application Programming Hub (Packet Tracer simulation), packettracer
Introduction to Packet Tracer 1: Overview of hubs

Connect to the received signal for regenerative shaping and amplification, to expand the transmission distance of the network, while all nodes are centered on it.

Working at the bottom layer (Physical Layer) of OSI (Open System Interconnection Reference Model ).

 

2. Hub Classification

Passive hub: No signal processing is performed, and the transmission distance of the media is not extended. The Hub broadcasts the signals it receives to all devices connected to it.
Active hub: The biggest difference from a passive hub is that it can shaping and amplifying signals to improve the transmission distance between the two devices.
Smart hub: In addition to the above two situations, it also provides network management and routing functions.

3. PC + Hub Simulation

Run Packet Tracer and click Terminal Device in the lower-right corner of the pop-up interface (marked with A in the figure). Then, the devices next to the Packet will display PCs, servers, printers, and phones, select a PC (marked with B in the figure) and drag it to the workspace (drag two PCs to the workspace ).
Then click the hub in the lower-right corner (marked with C in the Hubs diagram). Then, various Hubs will appear next to the device category. Let's select the first one (marked with D in the diagram) in the exercises, drag it to the workspace.
Now that our device has been selected, we need to connect each device with a line: Click the line icon in the lower right corner (marked with E in the figure), there will be many lines next to the device class, click the first line (marked as F in the figure)
 
Move the mouse to the work area and the mouse will change to "line head". When you click any device in the work area, the mouse will lead to a line, and then click another device, at this time, the two devices will be connected together and repeat these steps to complete the network topology in the figure.
The rest of the work is to configure the parameters of the PC and Hub to make it work.
To ping PC1 to PC2, set PC1 and PC2 in the same network segment, configure the network parameters of PC1 and PC2 respectively: follow the instructions shown in the figure, if you need to change the 3: IP Adress to 192.168.1.XX in the image for PC2 network settings, the xx here means not to be the same as the IP address of other hosts, and the Subbet Mask does not change to 255.255.255.0
After configuring the network parameters, we will use PC1 to ping PC2:
When we click Center 2, a cmd terminal will appear. In this terminal, enter ping 192.168.1.2, where "192.168.1.2" is subject to your IP address of pc2. (real-time mode) the running result is as follows:
(Simulation mode) running result: note that the above real-time mode needs to be adjusted to the simulation mode on the main interface before ping 192.168.1.2 on the cmd terminal:
Then ping 192.168.1.2 on the cmd terminal. Note that the result is not displayed yet. Because we are running in simulation mode, the ICMP of PC1 will not transmit data packets to pc2, because it requires step-by-step debugging.
During the debugging process, ICMP request packets are sent to PC1 --> Hub --> PC2, and then PC2's ICMP response packet PC2 ----> Hub ----> PC1, so that ping is completed.

Iv. Knowledge Extension

In the above simulation mode debugging, we can learn how the ICMP packet has changed from one device to another through one-step debugging. If we want to know how the packet has changed during this process, you need to perform the following operations: From this figure, we can see that the ping command packet consists of an Ethernet header, an IP header, and an ICMP packet.