SIM-06: Implementation of ECN+/Wait algorithm in ns-3

About project:

    ● Explicit Congestion Notification (ECN) is a signaling mechanism used to inform the TCP 
      sender about congestion.
    ● Whereas ECN+ is a minor extension of ECN wherein SYN/ACK packets also carry the ECN marks.
    ● This project is a further extension of ECN+.This algorithm is described in RFC 5562. 
     This project intends to implement ECN+/Wait in ns-3.

References:

    ● RFC 5562 (Link: ​https://tools.ietf.org/html/rfc5562​) 
    ● ECN support for TCP in ns-3 (Link: https://www.nsnam.org/docs/models/html/tcp.html#support-for-explicit-congestion-notification-ecn​)
    ● http://delivery.acm.org/10.1145/1090000/1080100/p61-kuzmanovic.pdf?ip=218.248.46.107&id=1080100&acc=PUBLIC&key=045416EF4DDA69D9%2E4A4590D5C9BCB165%2E4D4702B0C3E38B35%2E4D4702B0C3E38B35&__acm__=1541934899_2f78bd63fdd21f83bdb011453bd6d979

The following is the explaination of this repositry:

src:

This repositry contains the modified code for the implementation of ECN+.
It consists of files Tcp-Socketbase.cc, Tcp-Socketbase.h and the topology.

results:

This repositry contains the results obtained after running our files. It consists of pcaps for each node.

concept.md :

This file consists of the concept of ns-3 ECN and then ECN+ i,e.,why is it used and how it works etc..

Activities.md :

This file consists of the activities done by us in each week and our assumptions etc...

Report.md :

This file contains of the changes we have done to the ECN enabled Tcp-Socketbase files in order to 
implement ECN+

How to run the files:

     * Download the ns3-dev-gitmaster from ns3 repositry of github
     * extract the folder and build the tools necessary (works on ubuntu 16.04)
     * copy the following topology into the scratch folder.
     * copy the tcp-socketbase.cc and tcp-socketbase.h files in the respective locations src/internet/model/
     * run this with the command "./waf --run <topology-file name>
     * there will be a results repositry created. pcaps will be stored.open pcap for any node and you can 
       observe the packets flow from that node.

Group:

    ● shiva swaroop.v (16CO252)
    ● sanjith geddam  (16CO111)
    ● kunal M         (16CO227)