Exercise 2: The Four Headers Wrapping an HTTP Request — Possible Solution
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The four headers, in the order they get added (outermost added last):

1. TCP segment header -- added first, wrapping the raw HTTP request.
Per the chapter's own encapsulation example, this header "adds:
source/destination port" -- specifically the port the request is
being sent from and the port it's being sent to (e.g. port 443 for
HTTPS), which is what lets the receiving machine know which
application/connection the data belongs to.

2. IP packet header -- added next, wrapping the TCP segment (which
itself already contains the HTTP request). This header "adds:
source/destination IP address" -- the network-layer addressing
information needed to route the packet from the sending machine to
the correct destination machine across potentially many intermediate
networks.

3. Ethernet frame header -- added last, wrapping the IP packet. This
header "adds: source/destination MAC address" -- the hardware-level
addressing needed to deliver the frame across the immediate local
network segment (e.g. from the laptop to the router).

So by the time the original HTTP request is actually transmitted, it
exists inside three layers of headers total, in this order from
innermost to outermost: TCP header (port info) → IP header (IP address
info) → Ethernet header (MAC address info) -- with the original HTTP
request itself sitting at the very center, untouched by any of the
three headers wrapped around it.

(Four "layers" are referenced in the chapter's own diagram --
Application, Transport, Internet, Link -- but the Application layer
itself is the original HTTP request, not an added header; the three
headers actually added on top of it come from the Transport, Internet,
and Link layers respectively.)

WHY THIS WORKS AS AN ANSWER
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This lists the headers in the correct nesting order (TCP innermost,
Ethernet outermost) and states specifically what information each one
adds, quoting the chapter's own diagram directly rather than guessing
at header contents.