Handover

This project is the testbed implementation of a Software Defined Networking (SDN) framework for Enterprise WLANs (SDEW). The SDEW framework provides seamless, client-unaware handover for a mobile device moving from one AP to another. To understand the details of the SDEW framework, the seamless handover and the testbed implementation, kindly refer to the following papers:

1. An SDN framework for seamless mobility in enterprise WLANs
2. A NAT based seamless handover for Software Defined Enterprise WLANs
3. Testbed evaluation of a seamless handover mechanism for an SDN-based enterprise WLAN

The project uses hostapd (version 2.8), Floodlight OpenFlow Controller (version 0.90) and Click Modular Router (version 2.1). Additionally, dnsmasq also needs to be installed for the project to work.

Note: The project was tested in Ubuntu 18.04 LTS.

Modifications/Additions

For implementation of the proposed SDEW framework and the seamless handover mechanism, various modifications were made to the source files of the softwares. Additionally, many new files were also added.

hostapd

The directory ofSwitchAP was added inside the hostapd-2.8/src directory. All the relevant files, required for the implementation, were added to the ofSwitchAP directory. Additionally, various exisitng files were also modified. The following #define directives in the controller_interface.c file inside the ofSwitchAP directory needs to be changed to the appropriate values before compilation:

#define SOCK_ADDR "127.0.0.1"    // Change "127.0.0.1" to Floodlight OpenFlow Controller's IP address
#define IFACE "wlan0"            // Change "wlan0" to the name of the wireless interface of the AP
#define NATIFACE "eth0"          // Change "eth0" to the name of the ethernet interface of the AP
#define NATSUBNET "192.168.5.0"  // Change "192.168.5.0" to the subnet which the NATIFACE belongs to

Floodlight OpenFlow Controller

The directory ofSwitchAP was added inside the Floodlightv0.90/floodlight/src/main/java/net/floodlightcontroller directory. All the relevant FloodLight modules were added to the ofSwitchAP directory. Additionally, various exisitng files were also modified.

Click Modular Router

The PrintSignalStrength.cc and PrintSignalStrength.hh files were added to the click/elements/wifi directory.

Gateway

All the relevant files, required for the implementation of the Gateway were added to the Gateway directory. The following #define directives in the gatewayNAT.c file inside the Gateway directory needs to be changed to the appropriate values before compilation:

#define SOCK_ADDR "127.0.0.1"    // Change "127.0.0.1" to Floodlight OpenFlow Controller's IP address
#define IFACE "eth0"             // Change "eth0" to the ethernet interface towards the APs

Compilation

Kindly follow the compilation and installation guides for each of the softwares (hostapd, Floodlight OpenFlow Controller and Click Modular Router). Remember to clean the already compiled files first.

Gateway

For compiling the Gateway use the following commands:

$ make clean
$ make

Configuration

hostapd

A .config file is already created in the hostapd-2.8/hostapd directory. The file should not require any changes.

The hostapd.conf file contains all the configurations for hostapd. The ssid field denotes the SSID that will be created when hostapd will be run, and the wep_key0 field is the password of the created SSID.

Click Modular Router

The wifi module in Click Modular Router needs to be enabled for the project to work. Use the following command inside the click directory:

$ ./configure --enable-wifi

Execution

The Floodlight OpenFlow Controller needs to be started first, before running hostapd and/or Gateway. If hostapd and/or Gateway are/is started first, then it may result in Segmentation Fault.

Floodlight OpenFlow Controller

For running Floodlight OpenFlow Controller, run the following command inside Floodlightv0.90/floodlight directory:

$ java -jar target/floodlight.jar

hostapd

For running hostapd, run the following command inside Gateway directory:

$ sudo ./run_SDEW.sh <wireless interface> <ethernet interface>

For example, if the name of the wireless interface is wlan0 and that of the ethernet interface is eth0, then the above command will be run as follows:

$ sudo ./run_SDEW.sh wlan0 eth0 

Gateway

For running Gateway, run the following command inside Gateway directory:

$ sudo ./run_gw_nat.sh <ethernet interface towards the APs> <ethernet interface towards the remote host> <IP address of ethernet interface towards the APs>

For example if the name of the ethernet interface towards the APs is eth0, and the name of the ethernet interface towards the remote host is eth1 and the IP address of eth0 is 192.168.100.1, then the above command will be run as follows:

$ sudo ./run_gw_nat.sh eth0 eth1 192.168.100.1