Nwork Kazanç Planı

Wireshark
Rahul Hiran
TDTSComputer Networks and Internet
Protocols

Textbook: Computer Networking: A

2
Whats the Internet: Slide from lecture
1
PC millions of connected Mobile network
server computing devices: Global ISP
wireless
hosts = end systems
laptop running network
cellular Home network
handheld apps
communication links Regional ISP
fiber, copper, radio,
access satellite
points Institutional network
wired
links

routers: forward packets

3
Introduction
Whats a protocol?
(slide from lecture 1)
human protocols: network protocols:
whats the time? machines rather

I have a question than humans

4
Introduction
More about protocols
There are many protocols that are
involved in working of computer network
There is a internet protocol stack. A
protocol normally belongs to one of the
layers in the stack.
Let us look at the airline functionality

5
Layering of airline
functionality
ticket (purchase) ticket (complain) ticket

baggage (check) baggage (claim baggage

gates (load) gates (unload) gate

runway (takeoff) runway (land) takeoff/landing

airplane routing airplane routing airplane routing airplane routing airplane routing

departure intermediate air-traffic arrival

Layers: each layer implements a service

7
Introduction
Encapsulation

8
wireshark
How can we analyze the network
data?
Using tools such as wireshark
Wireshark: a network packet
analyzer. A network packet analyzer
will try to capture network packets
and tries to display that packet data
as detailed as possible.
Let us start wireshark.!
9
Start screen of wireshark

10
Make your own capture or open
existing trace files

11
Graphical User Interface

12
Reduce clutter
Disable the checksum error
messages from Views->Coloring
rulesmenu item
Enter data in the filter to show only
http packets
Let us look at the example

13
After unnecessary data is
removed

14
Let us look at the application level
data

15
Internet protocol stack
application: supporting network applications
FTP, SMTP, HTTP
application
transport: process-process data transfer
TCP, UDP
TCP is responsible for the establishment of a TCP
transport
connection, the sequencing and acknowledgment
of packets sent, and the recovery of packets lost
during transmission
network: routing of datagrams from source network
to destination
IP, routing protocols
Link
link: data transfer between neighboring physical
network elements
Ethernet, (WiFi), PPP
physical: bits on the wire

16
Introduction
Encapsulation

17
TCP header

18
TCP header data in our
packet

19
How to look at
time/sequence plot
Select tcp-ethereal-trace-1
Filter by entering tcp
Select TCP segment
Go to statistics-> TCP streamgraph
-> Time-sequence graph (stevens)

20
Internet protocol stack
application: supporting network
applications application
FTP, SMTP, HTTP
transport: process-process data transfer
TCP, UDP transport
network: routing of datagrams from
source to destination network
IP, routing protocols
The Internet layer is responsible for addressing,
Link
packaging, and routing functions.
link: data transfer between neighboring physical
network elements
Ethernet, (WiFi), PPP
physical: bits on the wire

21
Introduction
Encapsulation

22
Internet layer
Let us first open ip-ethereal-trace-1
And look at the first ICMP message
We also look at the IP protocol
header format

23
IP header

24
IP header in collected traces

25
Internet protocol stack
application: supporting network
applications application
FTP, SMTP, HTTP
transport: process-process data
transport
transfer
TCP, UDP
network: routing of datagrams from network
source to destination
Link
IP, routing protocols.
link: data transfer between physical
neighboring network elements
Ethernet, (WiFi), PPP
physical: bits on the wire

26
Introduction
Whats the Internet: Slide from lecture
1
Network layers job is end- Mobile network
to-end movement of data Global ISP
from source to destination
Link layers job is node-to-
node movement of Home network
network-layer datagrams Regional ISP
over a single link in the
path
Institutional network
Ethernet is quite popular
protocol
Let us look at the header

27
Introduction
Ethernet header and trailer

28
Conclusion
application: supporting network
applications application
FTP, SMTP, HTTP
transport: process-process data transport
transfer network
TCP, UDP
network: routing of datagrams from link
source to destination
physical
IP, routing protocols
link: data transfer between
neighboring network elements
Ethernet, (WiFi), PPP
physical: bits on the wire

29
Introduction
Conclusion

30
Questions?

31
funduszeue.info 32

IoT is a system that connects with the devices that are accessible through the internet. There are number of cloud platforms and protocols, MQTT is one of the most used IoT protocol for IoT projects. In our previous tutorial, we have connected MQTT with Raspberry Pi and ESP Now, we are establishing connection between MQTT server and ESP32.

ESP32 is a Successor of popular ESP Wi-Fi module, with many advanced features such as this module is a dual core bit CPU with built-in Wi-Fi and dual-mode Bluetooth with sufficient amount of 30 I/O pins.

While, MQTT stands for Message Queuing Telemetry Transport, it’s a system where we can publish and subscribe messages as a client. By using MQTT you can send commands to control outputs, read and publish data from sensors and much more. There are two main terms in MQTT i.e. Client and Broker.

What is MQTT Client & Broker? 

MQTT Client: An MQTT client runs a MQTT library and connects to an MQTT broker over a network. Both publisher and subscriber are MQTT clients. The publisher and subscriber refer that whether the client is publishing messages or subscribing to messages.

MQTT Broker: The broker receives all messages, filter the messages, determine who is subscribed to each message, and send the message to these subscribed clients.

Now, in this tutorial we will explain how to connect to a MQTT broker and subscribe to a topic using ESP32 and Arduino IDE libraries.

Components Required

Cloud MQTT Account Setup

To set up an account on Cloud MQTT navigate to its official website (funduszeue.info) and sign up using your email.

After login, click on ‘+ Create New Instance’ to create a new instance.

Now enter your instance name and select ‘Cute Cat’ in plan option.

In new tab select region and click on ‘Review’.

Your instance is created and you can view your details like user and password.

ESP32 MQTT Broker Code Explanation

The complete code for Connecting ESP32 with MQTT broker is given at the end. Here, we are using Arduino IDE to program ESP32. First, install WiFi.h library and PubSubClient library.

PubSubClient library allows us to publish/subscribe messages in topics.

Now declare some global variables for our WiFi and MQTT connections. Enter your WiFi and MQTT details in below variables:

In the setup_wifi function, it will check the WiFi, whether it is connected to network or not, also give the IP address and print it on the serial monitor.

In the below,while loop function, it will connect to the MQTT server and will print it on the serial monitor. This process will run in a loop until it gets connected.

Now we will specify a call back function and in this function, we will first print the topic name and then received message.

Testing MQTT with ESP32

Now to test the code upload this code into ESP32 using Arduino IDE and open the serial monitor.

To subscribe and publish to MQTT topics, a Google Chrome application MQTTlens will be used. You can download the app from here.

Launch this app and set up a connection with MQTT broker. To setup, connection click on ‘connections’ and in next window enter your connection details from Cloud MQTT account.

Save this connection, and  now you can subscribe and publish a message on your MQTT broker using ESP

To subscribe or publish a message enter your topic name in subscribe and publish option and enter the default message.

Your message will be shown on serial monitor as shown in the above image of the serial monitor.

Hence, we have successfully connected the MQTT broker with ESP32. Stay Tuned with us for more amazing IoT projects.