This is the story of my toughest certification ever. I had completed JNCIP-SP and I don't recall much of the struggle in achieving the same. But when I decided to get JNCIE-SP it was all different. I got a company to give lab attempt so I just booked for the lab without much preparation or idea.
But then to save each and every second in the time constraint lab exam, it is necessary to spend more and more time on these labs.
VMM / Junosphere has helped me to build, retrieve and snapshot all these lab topologies. Human tendency was to give importance to critical concepts but then we make mistakes on very small things.
It was clearly seen during lab work. It is important to make note of these silly mistakes and avoid them in the lab. Everyone does make mistakes on different areas but they always do the same mistake on all the lab attempts.
Apart from the above materials, I had to refer RFCs also to get better understanding of some topics. At the same time we need to restrict ourselves on the topics to avoid getting lost from the JNCIE track. This is important since the ultimate goal is to pass JNCIE exam in the given time frame.
Having noted down frequent silly mistakes, keyboard shortcuts and Junos shortcuts gave my first lab attempt. Like the majority I could not complete the lab and fell short of time. But this experience was "icing on the cake" to my JNCIE preparations.
JNCIE lab has plenty of troubleshooting and fixing the issues. There are tasks which only require straight forward configuration, but that comes at the end and the base network should be set right in the initial hours. It took quite some time to grab the topology and the tasks that need to be completed. Also realized that I need some more effort on Traffic Eng, BGP over IPv6 address and 6PE.
I gave one more attempt after couple of months and successfully passed the JNCIE-SP#2272.
When I look back it was not just the number but I gained very good knowledge from JNCIE.
Hope my experience helps other. All the best to everyone.