This figure uses an image similar to the one in figure 2.7, in which a desktop computer (labeled here as "Client host") and a server (labeled as "Server host") are placed side by side and from each of these a dotted line extends vertically downward. Here, the dotted lines are labeled "Time." This image similarly uses blue arrows to indicate the interaction between the computer and the server during an HTTP request and response. However, this image incorporates short blue cylindrical shapes that represent cookie files.

The client host computer begins the interaction with an existing cookie file, labeled "ebay: 8734." A blue arrow extends diagonally downward and to the right, from the client host timeline to the server host timeline; this arrow is labeled "usual http request msg." At the point in which the arrow intersects with the server host timeline, a note indicates: "Server creates ID 1678 for user." A black arrow extends from this point diagonally downward and further to the right towards a cookie file; this arrow is labeled "entry in backend database," and indicates that the user ID is being indexed for future identification of the user.

The interaction between client and server continues with a second blue arrow extending diagonally downward and to the left; this arrow is labeled "usual http response" and "Set-cookie: 1678." At this point on the client host timeline there is a cookie file, with two user IDs: "amazon: 1678" and "ebay: 8734."

From here, the interaction continues and a blue arrow extends diagonally downward to the right; this arrow is labeled "usual http request msg" and "cookie: 1678." Where the arrow intersects with the server host timeline, a note indicates: "Cookie-specific action." A black arrow points to the cookie file indexed in the backend database, and back from it.

The interaction continues as a blue arrow points diagonally downward and to the left; this arrow is labeled "usual http response msg." A one-week gap is indicated on the timeline, and then a blue arrow extends diagonally downward and to the right; this arrow is labeled "usual http request msg" and "cookie: 1678." Where this arrow intersects with the server host timeline, a note indicates: "Cookie-specific action." A black arrow points to the cookie file indexed in the backend database, and back from it.

The interaction concludes with a blue arrow extending diagonally downward and to the left, labeled "usual http response msg," and intersecting with the client host timeline.