Senior Network Software Engineer (WinSock / PTP)

Job Description

Position: Senior Network Software Engineer (WinSock / PTP)

Level: Senior

Location: Remote

Employment Type:Full-Time/ Part-Time

Working Hours: Palestine Time Zone with partial overlap with U.S. business hours

Contract Duration: ~4 Months contract (Extendable based on performance and client needs)

No. of vacancies: 2

Overview:

Overview

GGateway is seeking two Senior Network Software Engineerswith strong expertise in low-level Windows networking. We are building a command-line test tool for Windows Server with two parts: a high-throughput, multi-threaded Winsock UDP traffic tool, and a passive Precision Time Protocol (PTP) slave that measures a network card's hardware clock using hardware packet timestamps. One engineer will own the traffic tool and the other the PTP slave. The work focuses on packet-level control, hardware timestamping, throughput on 10 to 100 Gbps links, and measurement accuracy down to tens of nanoseconds. Strong experience in one of the two areas is required; experience in both is a plus.

Key Responsibilities

• Design, develop, and optimize user-mode Windows networking software in C++ using the Winsock API.
• Handle low-level socket programming for packet transmission, reception, and control messages, including message-based sends and receives with control data.
• Debug and measure network traffic at the socket and packet level: throughput, packet loss, reordering, and timestamp accuracy.
• Build a test tool that reports honestly: every API error logged with its code, results reported as measured, and a clear line between tool bugs and driver or hardware findings.
• Run and document long lab runs on real network cards, including 12-hour soak runs, and keep the evidence.
• Work with the customer's engineering team in weekly syncs, and deliver regular code drops with release notes.
• Write clean, efficient, well-tested C++ code with unit tests and documentation.

Traffic focus:

• Build multi-threaded UDP senders and receivers, one socket per thread, that reach 10 Gbps and beyond on 100 Gbps links.
• Apply and log socket options for IPv4 and IPv6: send and receive buffers, reuse and exclusive address use, timeouts, TTL, don't-fragment, packet info, and UDP connection reset.
• Detect loss, reordering, and duplicates from sequence numbers, and report live statistics per thread and in total.
• Run socket-exhaustion stress tests with 50 or more concurrent sockets, catching socket errors and driver resets.
• Tune performance on Windows Server: RSS, interrupt moderation, buffer sizing, and thread placement.

PTP focus:

• Implement a passive PTP slave per IEEE 1588v2 and the G.8275.2 telecom profile: unicast negotiation over UDPv4, grants and renewal, and the Sync, Follow_Up, Delay_Req, and Delay_Resp exchange.
• Read hardware receive and transmit timestamps and the network card's hardware clock through the Windows timestamping APIs.
• Compute and report offset, path delay, and frequency offset without adjusting any clock, and handle counter wrap, clock steps, and missing timestamps.
• Validate the measurement against an independent reference, the linuxptp NetSync Monitor, with a target agreement of 100 ns.
• Work against a Linux grandmaster running ptp4l, including its configuration and logs.

Required Qualifications

• Strong hands-on experience in Windows low-level networking (Winsock required).
• Strong proficiency in C++17 on Windows: Visual Studio, MSVC, CMake, and the Windows SDK.
• Deep knowledge of IP and UDP networking fundamentals: fragmentation, MTU, ICMP, IPv4, and IPv6.
• Experience building high-performance, multi-threaded networking applications.
• Strong experience in packet-level debugging with Wireshark or tcpdump, and in network performance measurement.
• Comfort with lab work: real network cards, switches, a Linux peer, and small scripts in PowerShell, Python, or Bash.
• Strong analytical, debugging, and problem-solving skills in complex system environments.
• Clear written English for customer syncs and release notes.

Traffic focus:

• Proven experience with high-throughput UDP on Windows at 10 Gbps or more.
• In-depth knowledge of Winsock socket options and their IPv6 equivalents.
• Experience tuning Windows Server networking: RSS, interrupt moderation, and socket buffers.

PTP focus:

• Hands-on experience with IEEE 1588v2 PTP: the end-to-end delay exchange, one-step and two-step operation, and the correction field.
• Knowledge of the G.8275.2 telecom profile and unicast negotiation.
• Experience with hardware timestamping on Windows.
• Experience with linuxptp: ptp4l, pmc, and nsm.

Nice to Have

• Understanding of NDIS and the Windows networking architecture: offloads, RSS, and how the miniport driver delivers timestamps.
• Registered I/O or overlapped I/O at high packet rates, and pktmon.
• Experience building test or validation tools for network drivers or network cards.
• Experience in both the traffic and the PTP areas.