OMNET++ OPENFLOW is currently the most prominent approach which implements the SDN concept and offers a high flexibility in the routing of network flows. OpenFlow standard is managed by the Open Networking Foundation (ONF).

Basic principle of openflow:

  • Added as feature to commercial switches.
  • It’s an open standard.
  • Separation of control and data-plane layers.

OPENFLOW versions with their features:

  • OpenFlow version 1.1.
  • Group actions.
  • Multiple flow tables.
  • OpenFlow version 1.2.
  • Extensible match support.
  • OpenFlow version 1.3.
  • Per flow meters.

Message types in OpneFlow:

  • Asynchronous messages.
  • Establishment of OpenFlow channel.
  • Modify-state and packet-out messages.

Sample code for OpenFlow:

#ifndef FLOW_TABLE_H_
#define FLOW_TABLE_H_
#include <list>
#include <openflow.h>
using namespace __gnu_cxx;
struct flow_table_counters {

struct flow_table_instructions {
    ofp_action_output actions[1];
struct entry_data {
    flow_table_counters *counters;
    flow_table_instructions *instruc;

struct ltmatch
    bool operator() (const oxm_basic_match m1, const oxm_basic_match m2) const
        if(m1.OFB_IN_PORT == m2.OFB_IN_PORT){
            return false;
        }else if(m1.OFB_ETH_TYPE == m2.OFB_ETH_TYPE){
            return false;
        }else if(m1.OFB_ETH_SRC == m2.OFB_ETH_SRC){
            return false;
        }else if(m1.OFB_ETH_DST == m2.OFB_ETH_DST){
            return false;
        }else if (m1.wildcards != m2.wildcards){
            return false;
        return true;
class Flow_Table : public cSimpleModule
    void addEntry(oxm_basic_match *match, entry_data* entry);
    bool deleteEntry(oxm_basic_match *match);
    bool lookup(oxm_basic_match *match);
    ofp_action_output *returnAction(oxm_basic_match *match);
    virtual void initialize();
    virtual void handleMessage(cMessage *msg);

    std::multimap<oxm_basic_match, entry_data, ltmatch> entry_map;
    int size;