A.3. Controlling the Network
This section provides an overview of how the network can be controlled in terms of providing routing decisions and deployment and explores some of the early mechanisms that offer some form of availability by hiding physical or addressing details of routers and other devices on the network. Additionally, it looks at error handling using ICMP and dynamic IP address allocation schemes offered by DHCP, which provide a context for VRRP's high-availability superiority over DHCP.
Let's begin with a brief overview of the Address Resolution Protocol, which is used to map IP addresses to the physical media address.