Resume2015
- 1. David Youngworth [email protected] (408) 728-3029 3566 Rutledge Common, Fremont, CA 94538 A skilled and flexible systems developer with a wide range of experience pursuing opportunities to design and build state-of-the-art networking and security solutions for distributed environments and mobile platforms. Technical Strengths • Systems and low-level applications development • Networking protocols, TCP emphasis • System and network performance • High performance data flow modeling • Code-level implementation and architecture • Behavioral usability design Preferred Languages: C, C++, Python, BASH OS: Linux/Ubuntu/RedHat, OSX, Windows, DataONTAP, GigaVUE H Series Professional Experience System Developer at Saisei Networks (March 2014 – present) Responsibilities: • Develop and enhance Saisei’s flow-policing, security, and analytics solution, a flow-based packet forwarding engine with highly granular, real-time visibility and policy control at Gigabit speeds. • Architect new solutions and algorithms to improve data and flow plane performance as well as reduce memory usage. • Uncover and architect solutions for issues involving app discovery and profiling, flow policing, and memory corruptions. • Develop and improve core features on all layers of the product, including memory pools, per-flow TCP state, accounting and stats, interprocess queues, object hierarchy and presentation to our REST based API, and script based applications. Highlighted Accomplishments: • Improved performance of Saisei’s product from 20K to >300K incoming flows per second by re-architecting and implementing a scheduling subsystem. This was instrumental in achieving our ambitious goal of 10G traffic throughput. • Architected a hierarchal representation of hosts for maximum efficiency and functionality. This made it possible to keep minimum statistics on 1 billion hosts in real-time while seamlessly upgrading recently active hosts, adding threat counters for hosts suspected of malicious behavior, and blacklisting hosts after they are proven a threat. • Designed and implemented per-flow TCP state machinery for RTT measurements and detecting TCP threats like DOS, probing attacks, and injection attacks. Integrated the per-flow threat detection with the host threat tracking and blacklisting feature. • Implemented fair queuing for the IPC to our DPI process to solve a memory leak and performance bottleneck. • Built the system health monitor and SMTP client for sending system reports and alerts. System Engineer at Gigamon (December 2012 – February 2014) Responsibilities: • Designed, developed, and tested solutions and algorithms in the GigaVUE H Series Traffic Visibility embedded system. • Triage and fix bugs and feature gaps by running real network traffic and statistics, analyzing Broadcom switch chip states, and using system logs and GDB. Highlighted Accomplishments: • Redesigned the GigaVUE distributed switch to behave in an expected and manageable way when network resources are shared between users. • Ensured clean, non-blocking system interactions during varying states of partial configurations. • Designed a new key space for expanded filter rules. Algorithmically reduced the search space for forwarding table resources, improving the configuration performance, minimizing disruptions, and decreasing space usage on the network chips. Projects: GigaVUE 3.0 and 3.1: Usability and Flow Mapping Developed a new engine to enable the Usability and Flow-mapping features, as well as true multi-tenancy. • Developed code to translate the logical map, rule, and priority constructs added by the users into tagging actions, forwarding tables, TCAM entries, and other chip-level state. • Developed the engine’s ability to audit the configuration state and send updates to the Broadcom chips and GigaSMART blades. • Designed reference mechanisms for TCAM entries and forwarding tables that minimize chip disruption on each card during port set modifications, map priority shifts, and filter rule changes. • Determined and redesigned the behavior of partial map configurations to preserve expected traffic flow. • Fixed bugs and feature gaps in the BCM SDK and driver daemon with chip entry allocation after filter template changes in the new 40G and 100G port cards.
- 2. GigaVUE advanced mode: multi-tenancy through rule expansion Developed Gigamon's rule expansion algorithm and redundancy detection multi-tenancy solution. • Developed a software solution to eliminate the need for forwarding table prioritization by converting the single tenancy limitation of the Broadcom TCAM architecture to multi-tenancy by representing all rule permutations. • Clarified the rule expansion algorithm and its varying resource limitations in different use cases using combinatorics. • Saved limited TCAM space by developing a mechanism for detecting redundant rules, or rules with the same source ports and identical or superseding filter attributes. • Developed and tested features to satisfy use cases provided by customer beta-testing, including ingress filters and default map behavior on no traffic hits. MTS (Member of Technical Staff) at Netapp — FlexCache dev team for WAFL File System (August 2010 – December 2012) Responsibilities: • Collaborated to develop new features and performance enhancements for the FlexCache product in Netapp's WAFL filesystem. • Planned, developed, and tested code that adds new functionality and improves performance of FlexCache. • Sustained functionality across major versions by analyzing and triaging bugs submitted by QA and FlexCache customers, and developing and unit testing the fix. Highlighted Accomplishments: • Ensured interoperability between FlexCache and other WAFL features. • Developed and tested the upgrade/revert procedure to ensure smooth transitions between versions in clustered filesystems • Worked on Inter-system networking blades in the cluster mode system, the API to the local system, and the RDB to keep FlexCache metadata consistent across the cluster. • Developed NFS and CIFs locking on FlexCache volumes to stay consistent with the origin volume. Intern at Netapp — FlexCache dev team for WAFL File System (Summer 2009) • Added code for dynamically fetching and displaying performance and iop statistics for the FlexCache feature using Ontap’s UI. • Worked with another intern debugging PyNFS, an open source suite of testing tools for NFS4. Intern at Netapp — Internal Tools (Summer 2008) • Responsible for testing and troubleshooting a new release of the XANT automated testing tool. • Designed, implemented, and documented a Python module for inserting JavaScript pop-up menus and context-sensitive help windows in the CGI that generates XANT’s GUI. Education University of California, Berkeley, College of Engineering, BS Computer Science (May 2010) Early Accomplishments: Eagle Scout (Summer 2006)