3 research outputs found
Tracing Internet Path Transparency
This project has received funding from the European Unionâs Horizon 2020 research and innovation program under grant agreement No 688421, and was supported by the Swiss State Secretariat for Education, Research and Innovation (SERI) under contract number 15.0268. The opinions expressed and arguments employed reflect only the authorsâ views. The European Commission is not responsible for any use that may be made of that information. Further, the opinions expressed and arguments employed herein do not necessarily reflect the official views of the Swiss Government.Peer reviewedPublisher PD
MUST, SHOULD, DON'T CARE: TCP Conformance in the Wild
Standards govern the SHOULD and MUST requirements for protocol implementers
for interoperability. In case of TCP that carries the bulk of the Internets'
traffic, these requirements are defined in RFCs. While it is known that not all
optional features are implemented and nonconformance exists, one would assume
that TCP implementations at least conform to the minimum set of MUST
requirements. In this paper, we use Internet-wide scans to show how Internet
hosts and paths conform to these basic requirements. We uncover a
non-negligible set of hosts and paths that do not adhere to even basic
requirements. For example, we observe hosts that do not correctly handle
checksums and cases of middlebox interference for TCP options. We identify
hosts that drop packets when the urgent pointer is set or simply crash. Our
publicly available results highlight that conformance to even fundamental
protocol requirements should not be taken for granted but instead checked
regularly
ECN with QUIC: Challenges in the Wild
TCP and QUIC can both leverage ECN to avoid congestion loss and its
retransmission overhead. However, both protocols require support of their
remote endpoints and it took two decades since the initial standardization of
ECN for TCP to reach 80% ECN support and more in the wild. In contrast, the
QUIC standard mandates ECN support, but there are notable ambiguities that make
it unclear if and how ECN can actually be used with QUIC on the Internet.
Hence, in this paper, we analyze ECN support with QUIC in the wild: We conduct
repeated measurements on more than 180M domains to identify HTTP/3 websites and
analyze the underlying QUIC connections w.r.t. ECN support. We only find 20% of
QUIC hosts, providing 6% of HTTP/3 websites, to mirror client ECN codepoints.
Yet, mirroring ECN is only half of what is required for ECN with QUIC, as QUIC
validates mirrored ECN codepoints to detect network impairments: We observe
that less than 2% of QUIC hosts, providing less than 0.3% of HTTP/3 websites,
pass this validation. We identify possible root causes in content providers not
supporting ECN via QUIC and network impairments hindering ECN. We thus also
characterize ECN with QUIC distributedly to traverse other paths and discuss
our results w.r.t. QUIC and ECN innovations beyond QUIC.Comment: Accepted at the ACM Internet Measurement Conference 2023 (IMC'23