CCNA semester 1 covers the basics of networking, tcp/ip and subnetting, VLSM, and some basic cisco commands.
Semester 2 covers some dynamic routing protocols, with the main focus on RIP, RIPv2, EIGRP and OSPFv2.
Semester 3 mainly has stuff on VLANs (and VTP). Wireless standards, wireless security, basic knowledge about CSMA/CA.
Semester 4 focuses on WAN, talking about things such as type of WAN lines (leased line, circuit-switched, packet-switched, broadband VPN) and what uses them like frame-relay, PPP etc.. Network security (how to best protect the cisco devices, and everything on the internetal network), and finaly network troubleshooting.
For the most part, that is the CCNA. I wrote down the important stuff directly from the cisco netacad site as i am on a CCNA course myself, so have direct access to all 4 semesters of material direct from cisco, so all them topics are the current CCNA.