At the left of this figure is a cloud representing the public Internet. From this cloud, three connections extend horizontally to the right. The top connection ends at a computer labeled "Laptop w/IPsec" and identified as "Salesperson in Hotel." Between the Internet and the Salesperson is an IP datagram, represented by a blue rectangle divided into three segments: IP header, IPsec header, and Secure payload." A blue arrow extends rightward from the datagram to the Salesperson.

On the middle connection we see an identical IP datagram as above, with a blue arrow extending from it towards a router labeled "Router w/IPv4 and IPsec." From the router, one connection extends to a server while another connection extends to a computer labeled "Branch Office." Between the router and the computer are two parts of the datagram headed toward the computer and labeled "IP header" and "Payload."

On the bottom connection we see the same router as on the middle connection; two connections extend from the router to two computers, and a third connection ends at a server, and these three devices are labeled "Headquarters." The datagram here moves from right to left rather than left to right, and from the server we see (right to left) the Payload and IP header moving towards the central router. From the router we see (right to left) the Secure payload, IPsec header, and IP header moving towards the public Internet.