{
  "abstract": "The Advanced Camera (AdvCam) upgrade of the Large-Sized Telescopes (LSTs) calls for a fully digital readout in which each front-end board streams data to the event-building servers over commercial 10 Gb/s Ethernet, using an FPGA implementation of Remote Direct Memory Access (RDMA) over Converged Ethernet v2 (RoCEv2). In a previous work, a customized RoCEv2 core integrated with the SLAC SURF UDP/MAC stack was shown to sustain near-line-rate data transfers from a Xilinx KCU105 to a server equipped with a Mellanox ConnectX-5 NIC. However, the AdvCam topology is an incast funnel: many 10 GbE links converge onto a single uplink, and bare Priority Flow Control (PFC) congestion management protocol is known to be unfair and to suffer from head-of-line blocking. This work extends the previous design with the Data Center Quantized Congestion Notification (DCQCN) algorithm. A protocol-level ns-3 simulation is used to validate the DCQCN dynamics and to explore the parameter space; an FPGA rate-limiter integrated into the SURF MAC reacts to incoming Congestion Notification Packets (CNPs) according to the DCQCN state machine; a cocotb testbench with an emulated Python switch verifies the firmware end-to-end against a Soft-RoCE receiver; and a three-sender incast hardware test on a DCQCN-enabled commercial switch reproduces the canonical fair-share, reactive-redistribution, and saw-tooth behaviour expected from a commercial RDMA NIC. The internal rate-limiter register is shown to track the measured RoCEv2 throughput cycle by cycle.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.35171",
  "author_total": 8,
  "authors": [
    {
      "name": "F. Marini"
    },
    {
      "name": "M. Bellato"
    },
    {
      "name": "A. Bergnoli"
    },
    {
      "name": "A. Griggio"
    },
    {
      "name": "R. Isocrate"
    },
    {
      "name": "L. Modenese"
    },
    {
      "name": "F. Montecassiano"
    },
    {
      "name": "M. Toffano"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/ej4vr261asmt1.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.35171",
  "fulltext_url": null,
  "id": "ej4vr261asmt1",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.35171",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.IM"
    ],
    [
      "openalex",
      "1705|Network Traffic and Congestion Control"
    ]
  ],
  "openalex": "W7224020195",
  "pdf_url": "https://arxiv.org/pdf/2610.35171",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-26",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/ej4vr261asmt1.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:35:35Z",
      "native_id": "2610.35171",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.35171"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.IM",
      "subfield": "instrumentation-methods"
    }
  ],
  "title": "A Congestion-Aware RDMA Front-End for LST Advanced Camera Readout",
  "title_text": "A Congestion-Aware RDMA Front-End for LST Advanced Camera Readout",
  "type": "preprint",
  "updated_at": "2026-10-30T12:35:35Z",
  "url": "https://research.draconitic.com/paper/ej4vr261asmt1",
  "venue": "arXiv",
  "versions": []
}