This guide details the step-by-step process for completing the activity. By the end of this lab, you will have established a redundant gateway system using Cisco's Hot Standby Router Protocol (HSRP) . Lab Overview
HSRP allows two routers to pretend to be one "Virtual Router" so the end-users never lose internet access if one router breaks. The Priority decides the boss, and Preemption ensures the boss gets his job back after a coffee break. 9.3.3 packet tracer - hsrp configuration guide