several fixups discussed on tuesday

Chapters/Background.tex

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+\chapter{Background} % Main chapter title
+
+\label{Background}
+
+\subsection{Nix: A Safe and Policy-Free System for Software Deployment}
+
+Nix addresses significant issues in software deployment by utilizing
+cryptographic hashes to ensure unique paths for component instances
+\cite{dolstra_nix_2004}. Features such as concurrent installation of
+multiple versions, atomic upgrades, and safe garbage collection make
+Nix a flexible deployment system. This work uses Nix to ensure that
+all VPN builds and system configurations are deterministic.
+
+\subsection{NixOS: A Purely Functional Linux Distribution}
+
+NixOS extends Nix principles to Linux system configuration
+\cite{dolstra_nixos_2008}. System configurations are reproducible and
+isolated from stateful interactions typical in imperative package
+management. This property is essential for ensuring identical test
+environments across benchmark runs.
+
+\subsection{UDP NAT and Firewall Puncturing in the Wild}
+
+Halkes and Pouwelse~\cite{halkes_udp_2011} measure UDP hole punching
+efficacy on a live P2P network using the Tribler BitTorrent client.
+Their study finds that 79\% of peers are unreachable due to NAT or
+firewall restrictions, yet 64\% reside behind configurations amenable
+to hole punching. Among compatible peers, over 80\% of puncturing
+attempts succeed, establishing hole punching as a practical NAT
+traversal technique. Their timeout measurements further indicate that
+keep-alive messages must be sent at least every 55 seconds to maintain
+open NAT mappings.
+
+These findings directly inform the evaluation criteria for this thesis.
+All mesh VPNs tested rely on UDP hole punching for NAT traversal;
+the 80\% success rate sets a baseline expectation, while the 55-second
+timeout informs analysis of each implementation's keep-alive behavior
+during source code review.
+
+\subsection{An Overview of Packet Reordering in TCP}
+TODO \cite{leung_overview_2007}
+
+\subsection{Performance Evaluation of  TCP over QUIC Tunnels}
+TODO \cite{guo_implementation_2025}