CCNA courses and CCNA certification program is to improve the skills of professionals in the home and small office networking segment.

CCNA certification is a foundation level certification to build a future in Computer Networking. CCNA is a pre-requisite for many of the advanced level certifications from Cisco

CCNA is a Certification and one requires to register and pass the Certification Exam for that. Short duration courses are preparatory courses to help one practice and pass the examination and is for the Networking professionals who already know and are working in this field.

For someone who has no experience or knowledge in the Networking should first target getting the requisite knowledge and judge the course curriculum for the appropriate duration of the course based on your current knowledge level and what you are planning to undertake.

Hope this helps
CareerAge Counselor