: Because there is no underlying operating system or virtual hardware to initialize, an IOU switch node boots up and reaches the user prompt in a matter of seconds.
The filename isn't just a random string of characters; it's a technical specification using Cisco's IOS naming conventions : i86bilinuxl2ipbasek9151gbin repack
image, primarily used to simulate Cisco Switch functionality (VLANs, Spanning Tree, EtherChannel) within a virtual lab. Why use a "Repack"? : Because there is no underlying operating system