The "twin" protocol of IP, the Internet Control Message Protocol (ICMP) is discussed. This includes the manner in which it supports IP, as well as useful commands, such as ping and tracert / tracert. Notions from ICMP are used to add some impotant aspects of IPv4 to what has been mentioned in previous videos.

The video is part of a lecture series made at home to continue online education during COVID-19 lockdown.