you can take CCIE written without any pre-requites;
however, it will be hard to study or pass without background experience with CCNA, CCNP;
For CCIE Lab you need a lot of labbing which may come from work experience or previous CCNP labs
You can take CCNP exams and pass all 3 but you will not get official cert paper until you pass CCNA.
As noted above, there are no prerequisites for CCIE... but the CCIE journey with just CCNA would be more erratic and quite painful as you would be dealing with many networking technologies unheard of before... Nevertheless it is doable this way too, for those who are determined and motivated enough...
The CCNP course curriculum and/or materials makes a great stepping stone toward the CCIE R&S. However as others have mentioned, there is no certification pre-requisite for the program. The cost of the CCNP exams is negligible in the scheme of things. So why not use those exams as a gage of your progress and obtain the CCNP on the way?
What Paul says makes perfect sense... The road to CCIE is long, and really is without any interim accomplishments. You have to pass your written (while cool, it's not a certification) and then you have to get all the way to passing your lab before you "get something" for your efforts.
The professional tracks are good paths for studying and earning some smaller accomplishments while still following a good study plan about most technologies that you'll need for the lab!
As the members have stated above, the CCIE certifications do not have any formal pre-requisite requirements. However, you are expected to have an in-depth understanding of the topics in the exam blueprints and strongly encouraged to have three to five years of job experience before attempting the certification.
Please visit the CCIE R&S page for more information https://learningnetwork.cisco.com/community/certifications/ccie_routing_switching
Cisco Learning Network Moderator
Vijay, best of luck on your journey! There are lots of us here on the CLN working on the same exams, so be sure to participate here. Nothing like having a ton of people that can answer questions - or even better - if you can start trying to answer some of them, that is the real test of your knowledge!
Again, best of luck.