Configuring Mininet with Floodlight Controller

Configuring Mininet with Floodlight controller is pretty straight-forward.

First, download and build Floodlight.

$ git clone git://github.com/floodlight/floodlight.git
$ cd floodlight
$ git checkout stable
$ ant
$ sudo mkdir /var/lib/floodlight
$ sudo chmod 777 /var/lib/floodlight

Once built, you can execute Floodlight by,
$ java -jar target/floodlight.jar

Execute Mininet and connect to the controller.
sudo mn --arp --topo tree,3,2 --mac --switch ovsk --controller remote,ip=127.0.0.1

Now if you connect to the Floodlight UI in browser, you may view the nodes emulated by Mininet.
http://127.0.0.1:8080/ui/index.html

Floodlight Dashboard

Network Topology

$ java -jar target/floodlight.jar

$ git clone git://github.com/floodlight/floodlight.git $ cd floodlight $ git checkout stable $ ant; $ sudo mkdir /var/lib/floodlight $ sudo chmod 777 /var/lib/floodlight - See more at: http://www.projectfloodlight.org/getting-started/#sthash.SaGU01pP.dpuf

$ git clone git://github.com/floodlight/floodlight.git $ cd floodlight $ git checkout stable $ ant; $ sudo mkdir /var/lib/floodlight $ sudo chmod 777 /var/lib/floodlight - See more at: http://www.projectfloodlight.org/getting-started/#sthash.SaGU01pP.dpuf

$ git clone git://github.com/floodlight/floodlight.git $ cd floodlight $ git checkout stable $ ant; $ sudo mkdir /var/lib/floodlight $ sudo chmod 777 /var/lib/floodlight - See more at: http://www.projectfloodlight.org/getting-started/#sthash.SaGU01pP.dpufss

$ git clone git://github.com/floodlight/floodlight.git $ cd floodlight $ git checkout stable $ ant; $ sudo mkdir /var/lib/floodlight $ sudo chmod 777 /var/lib/floodlight - See more at: http://www.projectfloodlight.org/getting-started/#sthash.SaGU01pP.dpuf

Quick trips are the best.

The view from the balcony in Portimão.

[12th - 13th, September] Nothing beats a quick trip to a beach resort in the summer. However, autumn is good too, with lesser tourists and cheaper rates, as long as it does not rain. Visiting Portimão end of the summer was good, with sun and beach, still abundantly available.

Delete Skype History in Ubuntu 14.04 LTS

If you are a Skype user in Linux, you would have noticed that there is no way of deleting the chat history, which is readily available in Windows. This has already been reported to Skype team by a few users before.

If you are wondering how to remove the history locally, this below answer from askubuntu.com will be helpful.

I was instructed by Skype customer service to do following:

1. Go to Options -> Privacy and set "Keep chat history for.." to Disable History, then sign out & sign in.
2. Go to $HOME/.Skype/my_skype_name/ and delete only main.db. Sign out & Sign in.

It worked.

Not sure why this was not the accepted answer. Works perfectly without a windows VM. However, it is strange that Skype team did not attempt to fix this glitch yet.

Memories of Croatia

View from the apartment in Rijeka

I often find it hard to fix my mind on whether to visit a new place, or a place that I have visited and enjoyed a lot once more. I visited Stockholm for the 3rd time recently for the EMDC Summer Event 2015. That was the last EMDC event as 2014 was the last intake of EMDC. I stayed in Stockholm for just 4.5 months. Still it left very nice memories, and going back early this summer in May and now again in August gave life to strong memories of 2013.

So far I have lived in Colombo, Lisbon, and Stockholm. Since I am still in Lisbon, I do not miss it right now. I also have lived in Rijeka, Croatia for 22 days. Though that was a very short period, I had a routine life with cooking, working, and going to the nearest super market. I also had some time to travel during the weekends, to the nearest cities. It was a short-stay. But Rijeka is clearly recorded in my mind. In the future, if I ever go back to Rijeka, I will get the memories back. I do not think I will ever go back to Rijeka, as I do not foresee the reason. But I cannot say for sure. In 2013, I never would have guessed that I would go back to Fejan in 2015 for another summer event.

My memories of Croatia includes working with my computer with the noise of frogs, while sitting outside the University of Rijeka in the stair case, in the mid night! They just close the faculty by 10 pm, and I did not have internet connection in my big and beautiful apartment (that was supposed to be a professors apartment. The topmost floor of the students' dormitory. Loved it). All the COST actions of the same program are listed here, including mine.

During my second trip to Stockholm, I did not pay a visit to KTH main campus. This time, I did. However, I did not visit Kista even this time. Kista is where I lived during my stay of 4.5 months in Stockholm. I stayed in the student apartments in the upper floors above a shopping mall.

In 2013, I came back to Lisbon two times for short trips, from Stockholm. In 2015, it is from Lisbon to Stockholm, two times. I admire the random patterns that appear in my life.

ShareLatex and local compilation of Latex

ShareLatex is good at swallowing the compilation errors and still producing the correct PDF. However, when locally compiling, the local errors often prevent the compilation. For example, TexStudio often fails for similar or same errors. Typing "Enter" upon encountering such errors will make the compilation proceed, regardless of such error reports.

! Missing $ inserted.
> Check empty or blank lines between the \begin{equation} and \end{equation} tags.

! You can't use `\eqno' in horizontal mode.
> Check the closing braces in the equations.

! Missing $ inserted.

                $
l.112 $\forall$ n $\in$ $\mathbb{Z}$^{+}: $C_
                                             {Nn}$ represents the coordinato...

> Changing
$\forall$ n $\in$ $\mathbb{Z}$^{+}: $C_ 
into
$\forall$ n $\in$ $\mathbb{Z} ^{+}$: $C_
fixed this.