In this illustration, we see a router labeled "Home agent, HA: 128.119.40.7," a router labeled "Foreign agent, COA: 79.129.13.2," and a laptop labeled "Mobile agent, MA: 128.119.40.186" arranged horizontally side-by-side. Dotted lines extend vertically downwards from each, representing the passage of time. The foreign agent and the mobile agent are designated as the "Visited network: 79.129.13/24."

A blue line extends diagonally downwards to the right from the Foreign Agent's timeline to the Mobile Agent's timeline. This arrow is associated with a blue text box that appears like this:

ICMP agent adv.

COA: 79.129.13.2 ...

A blue arrow extends diagonally downward to the left from the Mobile Agent to the Foreign Agent, and includes:

The blue arrow continues from the Foreign Agent to the Home Agent, and includes:

Registration req.

A blue arrow extends diagonally rightward from the Home Agent to the Foreign Agent, and includes:

Registration reply

The blue arrow continues from the Foreign Agent to the Mobile Agent, and includes:

Registration reply