For my CCNP BSCI studies, I needed to have some hands on ISDN technology in order to remember the IOS commands. All simulation software that I worked with (Boson Netsim, Packet Tracer, RouterSim Network Visualizer) were great for CCNA studies. However, they do not include any support for ISDN. It was clear that I needed to find another simulator.
Searching for an ISDN simulator
While searching forums, I found about the Adtran Atlas 550. It’s a ISDN simulator that’s used among CCIE candidates and Telecom engineers. However, it costs around 640$. I did not have the means to buy one of those. Besides, there were strict import regulations that allow only business owners to receive equipement from abroad. As a regular Cisco certification student, this was not possible. I thought of borrowing some equipement from my company, but I found out that we did not have Cisco routers with BRI interfaces (although we had Nortel ARN and ASN!).
One day I sat down and opened Notepad. I wrote down all ISDN-related IOS commands. Then, I repeated the cycle until I was recalling them fast. It was a small discovery: how did I not think of this earlier? Notepad is my friend! This is so easy to do. But, this method still does not enable you to learn all the ISDN scenarii .
If you are like me and were scared of ISDN at first when doing CCNA studies, let me reassure you that it does not have to be that way. Launch Notepad and start memorizing commands.