This image is the workhorse of virtual routing labs. Because it is based on IOS 15.7, it supports the majority of routing protocols required for and CCIE Enterprise Infrastructure labs.
Complete Guide to Cisco IOU L3 Image: i86bi-linuxl3-adventerprisek9-m2.157-3.M.bin i86bi linuxl3-adventerprisek9-m2 157 3 may 2018.bin