ICND 100-105 is also known as CCENT which is your primary gateway into the Cisco's Networking world. The course not only covers the concepts of computer inter-networking through Cisco's equipment but also clarifies the basic underlying concepts which are considered mandatory to learn and acquire any networking certification online.

This course covers all of the topics included in the official Cisco Syllabus for ICND 1 v3 extensively. But, to clear the exam, taking only this course is not enough. You are strongly advised to go with the official cert guide book.