Exploring new things

Upgrade to the latest version of Ubuntu -Using terminal 1. Make sure you have the update-manager-core package sudo apt install update-manager-core 2. To choose which version of Ubuntu you want      whether an LTS version or a normal version. In the file /etc/update-manager/release-upgrades , we need to make sure Prompt=normal for normal releases. (you can also choose Prompt = lts for only LTS releases) **Use any text editor** sudo gedit /etc/update-manager/release-upgrades Edit the Prompt option as per your wish. It is always better to keep it normal. 3. Pre-upgrade steps sudo apt update sudo apt upgrade sudo apt dist-upgrade Make sure all the packages are up to date in your system. Optionally, use sudo apt autoremove  to clear unwanted packages 4. Check whether a new version is available for your system do-release-upgrade -c 5. UPGRADE~! sudo do-release-upgrade The process starts!!! Press ENTER and typ...

CREATE CUSTOM TOPOLOGY IN MININET To create a custom topology in the mininet environment, we are going to use a python code. It is very simple, no need to acquire deep knowledge of python programming language especially for this task. 1. Import necessary packages *Topo from mininet.topo import Topo subpackage topo is being imported from the package mininet. 2. Create a class object class MYTOPO ( Topo ) : (Don't forget to have a similar class name and filename) 3. Create init method init method in python has similar functions as constructors in java. def __init__( self ):    Topo.__init__( self ) 4. Add Hosts Hostname=self.addHost ( "hostname" ) 5. Add switches switch_name=self.addSwitch ( "switch name" ) 6. Add links self.addLink ( "node name 1", "node name 2" ) 7. Name your topology Finally, we name the topo to call it in the command line. topos = { 'cust': ( lambda: MYT...

The default topology in mininet consists of two hosts and two switches. There are many other topologies available in mininet, such as single  single creates a topology with a single switch attached to the number of hosts that are mentioned by the user sudo mn --topo single,[no_of_hosts] Fig 1. [ sudo mn --topo single,2 ] reversed  reversed creates a topology similar to the single command but the interfaces are assigned in a reverse order sudo mn --topo reversed,[no_of_hosts] Fig 2. [ sudo mn --topo reversed,2 ] linear  The linear keyword creates a linear topology with the specified number of switches and hosts sudo mn --topo linear,[no_of_switches],[no_of_hosts_for_each_switch] Fig 3. [ sudo mn --topo linear,3,2 ] tree  The tree keyword creates a tree topology of the specified depth of switches. We can also specify the number of children sudo mn --topo tree,[depth],[no_of_children] Fig 4. [ sudo mn --topo ...

Software-Defined Networking is defined by “ the decoupling of control and packet-forwarding planes in the network ”. TRADITIONAL NETWORK The static architecture of traditional networks is Decentralized Complex Hardware-based LIMITATIONS OF TRADITIONAL NETWORK Only dedicated devices can be used Devices built for this sole purpose are only used Flexibility is a challenge Adaptability of the network is limited Inability to scale It is difficult to add or remove devices in the network Vendor lock-in The devices manufacture by a single manufacturer should be used throughout the network SOFTWARE DEFINED NETWORK  The networks are directly connected to applications through application programming interfaces (APIs)  It improves application performance and security It helps in creating a flexible, dynamic network architecture that can be changed as needed SDN ARCHITECTURE CONTROL PLANE The control plane is fre...

dpctl command in mininet The dpctl program is a command-line tool for monitoring OpenFlow switches. It can show the flows, features, configuration, table entries, etc. of the switches. It can work with any OpenFlow switches. dpctl is a switch management utility. dpctl show Shows the basic information of the switch, its flow table, ports. 2. dpctl dump-desc [switch] Prints switch description 3. dpctl dump-ports [switch] Prints port statistics of the network devices attached to the switch 4. dpctl dump-ports-desc [switch] Gives detailed statistics of the network devices attached to the switch 5. dpctl dump-flows [switch] Print all flow entries in the associated switch dpctl dump-flows [switch] [flow] Print all the matched flows in the associated switch Flows and flow table: Before data transfer Stimulating TCP data transfer Observing TCP flows in switches Stimulating ICMP flows using pingall and observing...

COMMUNICATION IN THE NETWORK Data can be transferred in a network using the following methods: [ Hint: Use xterm to access separate CLI for hosts ] [ Ex: xterm h1 h2 ] 1. Using SimpleHTTPServer and wget : SimpleHTTPServer is a python based server application for hosting the files in a system to anyone with the system's IP address. wget is used to obtain the file from the server. This results in obtaining a default file 'index.html' from the server. To run a server: python -m SimpleHTTPServer 80 & To run a client: wget -o - [server_ip] Server started: File has been accessed and stored on the client-side: Acknowledgment sent to the server: Thus a file is being transferred between the hosts. 2. Using iperf Iperf is a widely used tool for network performance measurement and tuning. It helps in transferring actual data between the hosts. It can transfer data in two ways: TCP transfer Server: iperf -s Client: iperf -c [s...