Legitimate Cisco IOS release names follow patterns like:
modern Cisco IOS L3 (Layer 3) emulation for network engineering training i86bilinuxl3adventerprisek9m21573may2018bin portable
: The host operating system required to run this specific bin file. : This confirms it is a image, meaning it simulates a (rather than an "l2" switch image). adventerprisek9 : This is the "feature set." It stands for Advanced Enterprise Legitimate Cisco IOS release names follow patterns like: