  In the last 15 years, the Internet architecture has continued evolving
organically, introducing new headers and protocols to the classic TCP/IP stack.
More specifically, we have identified two major trends. First, it is common
that most communications are encrypted, either at L3 or L4. And second, due to
protocol ossification, developers have resorted to upper layers to introduce
new functionalities (L4 and above). For example, QUIC's connection migration
feature provides mobility at L4.
  In this paper we present a reflection around these changes, and attempt to
formalize them by adding two additional protocol headers to the TCP/IP stack:
one for security, and another for new functionalities. We must note that we are
not presenting a new architecture, but trying to draw up what it's already out
there. In addition, we elaborate on the forces that have brought us here, and
we enumerate current proposals that are shaping these new headers. We also
analyze in detail three examples of such trends: the Zero Trust Networking
paradigm, the QUIC transport protocol, and modern SD-WAN systems. Finally, we
present a formalization of this architecture by adding these two additional
layers to the TCP/IP protocol stack. Our goal is triggering a discussion on the
changes of the current Internet architecture.
