Multipath-Load-Balancing

Method of managing incoming traffic by distributing and sharing load fairly among multiple routes from source to destination hosts

This network has 4 different paths available from host1 to host8.

Paths:
------
Path1 – {S1-S2-S4-S7}
Path2 – {S1-S2-S4-S6-S7}
Path3 – {S1-S2-S3-S4-S7}
Path4 – {S1-S2-S3-S4-S6-S7}

Usually packets will be transferred from host1 to host8 using any one of these 4 paths.
But in case of this algorithm, we will split the packets into any 2 paths to reduce the transfer time.

How to use this code?

Open a linux/Ubuntu terminal
Install mininet

>> sudo apt-get install git
>> git clone git://github.com/mininet/mininet
>> git checkout -b 2.2.0b3
>> ~/mininet/util/install.sh -a

Install ryu controller

>> sudo apt install ryu-bin

Open new command window & load your mininet model in it

>> sudo mn --custom ex_simple.py --topo simple_topo --controller=remote

Open another command window & start the ryu-controller in it
Run ryu-controller using your ryu_multipath.py code

>> ryu-manager --observe-links ryu_multipath.py

Ping from one host to another host in mininet

mininet> h1 ping h2 -c4

Now, see check the packets entering input port & packets leaving output ports
The no. of packets will be splited into 2 ports to balance load

mininet> sh ovs-ofctl dump-ports s1

How this code works?

Algorithm will

1. Find all possible path between source & destination hosts using DFS(Depth First Search)
2. Find 2 most optimal paths out of all the available paths
3. Install the corresponding flow entries from ryu controller to switch's group table using OpenFlow protocol

Examples: Other Network Topologies