The 640-554 Implementing Cisco IOS Network Security (IINS) exam tests candidates' knowledge of securing Cisco routers and switches including implementing authentication, authorization and accounting using technologies like TACACS+ and RADIUS. The exam covers topics such as common security threats, implementing access control lists, firewall technologies, intrusion prevention systems, VPN technologies and securing network management. Candidates can prepare for the exam by taking the Implementing Cisco IOS Network Security course.