Exploring new things

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...

What to do when an exception caught error pops up in mininet? 1. If mininet crashes for some reason, the application runs a clean up once being run again. 2. If that does not work, we can run clean up manually using Command: The result is as follows:

To create a simple network in mininet, the following steps should be followed. 1. Open terminal 2. Ensure mininet is installed  3. Enter command: sudo mn This creates a simple network with two hosts connected to an OVS switch, which in turn is connected to the inbuilt sdn controller DETAILS OF THE NETWORK To retrieve metadata regarding the network, the following commands can be used  nodes This command displays the nodes in the network links This command displays the links in the network ports This command displays the ports used in the network intfs This command displays the interfaces available in the network dump This command displays the overall information of the network including hostname, hostip, interfaces, controller information, etc. CONNECTIVITY BETWEEN HOSTS To ensure connectivity between the hosts, the following commands are used pingall pingall helps the us...