Improved writing

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2026-03-18 23:57:01 +01:00
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@@ -10,9 +10,9 @@ realistic conditions are scarce.
This thesis addresses that gap. We benchmark ten peer-to-peer VPN
implementations across seven workloads and four network impairment
profiles, producing over 300 unique measurements. We complement these
performance benchmarks with a source code analysis of each
implementation, verified by the respective maintainers. The entire
profiles. We complement these performance benchmarks with a source
code analysis of each implementation, verified by the respective
maintainers. The entire
experimental framework is built on Nix, NixOS, and the Clan deployment
system, so every result is independently reproducible.
@@ -20,10 +20,10 @@ system, so every result is independently reproducible.
Peer-to-peer architectures can provide censorship-resistant,
fault-tolerant infrastructure because they have no single point of
failure \cite{shukla_towards_2021}. IoT edge computing, content
delivery networks, and blockchain platforms like Ethereum all rely on
some form of peer-to-peer topology. But these benefits only hold when
nodes are spread across diverse hosting entities.
failure \cite{shukla_towards_2021}. Blockchain platforms like Ethereum
depend on this property, as do IoT edge networks and content delivery
systems. But these benefits only hold when nodes are spread across
diverse hosting entities.
In practice, this diversity remains illusory.
Amazon, Hetzner, and OVH collectively host 70\% of all Ethereum nodes
@@ -64,8 +64,9 @@ consumer-grade NAT can therefore participate as a first-class peer
in a distributed system.
The Clan deployment framework uses Nix and NixOS to eliminate
configuration drift and dependency conflicts. The result is that a
single administrator can reliably self-host distributed services.
configuration drift and dependency conflicts, which makes it
practical for a single administrator to self-host distributed
services.
Overlay VPNs are central to Clan's architecture: they supply the
peer connectivity that lets nodes form a network regardless of
physical location or NAT situation.
@@ -84,19 +85,21 @@ than systematic evaluation, which motivated the present work.
Existing research offers only partial coverage of this space.
Lackorzynski et al.\ \cite{lackorzynski_comparative_2019} benchmark
OpenVPN, IPSec, Tinc, Freelan, MACsec, and WireGuard in the context
of industrial communication systems, measuring point-to-point
throughput, latency, and CPU overhead. Their work does not address
overlay network behavior such as NAT traversal or dynamic peer discovery.
of industrial communication systems. They measure point-to-point
throughput, latency, and CPU overhead but do not address overlay
network behavior such as NAT traversal or dynamic peer discovery.
The most closely related study by Kjorveziroski et al.\
\cite{kjorveziroski_full-mesh_2024} evaluates full-mesh VPN solutions
for distributed systems, analyzing throughput, reliability under packet
loss, and relay behavior for VPNs including ZeroTier. However, it
focuses primarily on solutions with a central point of failure and
limits its workloads to synthetic iperf3 tests. This thesis extends
that work: it evaluates a broader set of VPN implementations with
emphasis on fully decentralized architectures, tests them under
application-level workloads (video streaming, package downloads),
applies multiple network impairment profiles, and provides a
for distributed systems, looking at throughput, reliability under
packet loss, and relay behavior for VPNs including ZeroTier. However,
it focuses primarily on solutions with a central point of failure and
limits its workloads to synthetic iperf3 tests.
This thesis extends that work in several directions. It evaluates a
broader set of VPN implementations with emphasis on fully
decentralized architectures and tests them under application-level
workloads such as video streaming and package downloads. It also
applies multiple network impairment profiles and provides a
reproducible experimental framework built on Nix, NixOS, and Clan.
A secondary goal was to create an automated benchmarking framework
@@ -111,17 +114,16 @@ This thesis makes the following contributions:
\begin{enumerate}
\item A benchmark of ten peer-to-peer VPN implementations across
seven workloads (including video streaming and package downloads)
and four network impairment profiles, with over 300 unique
measurements.
seven workloads and four network impairment profiles. The workloads
include video streaming and package downloads alongside synthetic
throughput tests.
\item A source code analysis of all ten VPN implementations. Manual
code review was combined with LLM-assisted analysis and the results
were verified by the respective maintainers on GitHub.
\item A reproducible experimental framework built on Nix, NixOS,
and the Clan deployment system. All dependencies are pinned,
system configuration is declarative, and cryptographic material
is generated deterministically, so every result can be
independently replicated.
and the Clan deployment system. Dependencies are pinned and system
configuration is declarative, down to deterministic cryptographic
material generation. Every result can be independently replicated.
\item A performance analysis showing that Tailscale outperforms the
Linux kernel's default networking stack under degraded conditions,
and that kernel parameter tuning (Reno congestion control in place