Java: Stream Control Transmission Protocol (SCTP)

If you have not heard about SCTP, don't fret! Me neither, until recently.

For a good explanation about SCTP, you can read this and this and this. In short, SCTP is basically TCP on steroids!

People who knows me well knew that I am always curious about new technology or technology new to me (sorry if I confuse you :).

How can I miss the chance to explore SCTP futher? Of course, the language of choice would be Java - still my favorite language after all these years.

First, I created the SctpServer class to serve as a SCTP server.
Next, I created the SctpClient class to serve as the SCTP client that will connect to multiple SCTP servers started on different ports (same host in this case) through a single socket (YES, you read it right, single socket!).

Two SctpServers listening on port 12000 and 12001. An SCTP client sends message to them on the same socket.

From the image above, you can see that there are 2 SctpServer listening on port 12000 and 12001 respectively.

Once the ScptClient connects to them and send them messages, you can see both servers reported that the connection came from port 43975 with stream number of 0 (SctpServer that listens on port 12000) and 1 (SctpServer that listens on port 12001) respectively.

SctpClient uses SctpMultiChannel for its communication.

Now, if you take a look at the codes for SctpClient, there is no "connect" statement at all. That is because a new association will automatically be created for every "send" command. [reference]

The destination of your message/data is now encapsulated in the MessageInfo object.

If you have the interest to explore SCTP further, you can download the sample codes here.

Enjoy hacking!

Java: Telnet Client

I was going through my personal projects in search for a topic to write for this blog when I stumbled upon this very old codes.

I wrote this back in Year 2003 and that was 12 years ago!

Back then, I was learning Java and somehow got hooked on reading RFCs. So, I guess it was natural for me to write a Telnet Client based on Telnet RFCs. I have to admit upfront that I did not implement all of them, but basic things do work :)

RFC

CODES

Just for the fun of it, I installed a telnet server on a CentOS 7 VM image and had the Telnet Client connects to it.

Guess what? It still works (phew :).

RFC

If you want to have a good laugh on some codes written by a Java newbie back in Year 2003, you can download it here.

Happy hacking!