Network Architecture & Design
Enterprise and datacenter designs built for redundancy, plus assessments that modernize OSPF/BGP routing and datacenter-to-datacenter connectivity.
Building networks that are fast, resilient & secure.
I'm David Phan. For over a decade I've designed and secured enterprise, datacenter and cloud networks on Cisco and Palo Alto platforms for organizations across a wide range of industries, and I use Python and vendor APIs to automate them.
dphan@core-01$ show profile
role : "Network Security Architect"
focus : [enterprise, datacenter, cloud]
sectors : [healthcare, finance,
insurance, oil & gas, airlines,
distribution, software, ...]
firewalls : [ASA, Firepower, Palo Alto]
access : [AnyConnect, GlobalProtect, MFA]
cloud : Azure, Palo Alto SD-WAN
automates : Python, Expect, vendor APIs
status : up # 24/7
dphan@core-01$
13+Years in networking
200+Managed sites supported
3Cisco certifications
7+Industries served
Industries served
- Healthcare
- Financial services
- Insurance
- Oil & gas
- Airlines
- Distribution
- Software
- and more
01 / Expertise
What I do
I design secure networks built on Cisco and Palo Alto, from the datacenter core to the cloud edge, and automate them so they're easier to run.
Next-Generation Firewalls
Designing and deploying Cisco and Palo Alto firewall platforms, including multi-vendor firewall migrations.
Secure Access & Threat Protection
Remote access VPN with multi-factor authentication, plus endpoint and DNS-layer protection rolled out across multiple regions.
SD-WAN & Hybrid Cloud
Palo Alto SD-WAN across diverse circuits, extended into Azure for secure, resilient cloud connectivity.
Network Automation
Python tools that migrate firewall configurations between vendors, and API-driven scripts that significantly cut troubleshooting and resolution time.
Pre-Sales & Consulting
Technical consultations, proposals, product demos and proof-of-concept testing, working with sales to tailor solutions to each client.
Cisco
Palo Alto
Automation
Also
02 / Experience
Where I've worked
From staging equipment and running NOC teams to architecting secure networks for clients across many industries.
Network Security Architect
Cumberland Group · Atlanta, GA
- Architect enterprise and datacenter networks for clients in healthcare, financial services, insurance, oil and gas, airlines, distribution, software and other industries.
- Design and deploy Cisco ASA/Firepower and Palo Alto firewall solutions, including Palo Alto SD-WAN across diverse circuits and secure production connectivity into Azure.
- Design remote access VPN on Cisco AnyConnect and Palo Alto GlobalProtect, secured with multi-factor authentication.
- Lead network assessments that redesign IGP/EGP routing and datacenter-to-datacenter connectivity for stronger redundancy.
- Build Python automation that migrates firewall configurations between vendor platforms, and API-driven tools that significantly cut troubleshooting and resolution time.
- Roll out endpoint and DNS-layer protection at scale with Cisco AMP for Endpoints, Palo Alto Cortex XDR and Cisco Umbrella across multiple regions.
- Design Cisco Meraki architectures that integrate with existing datacenter, cloud and remote-site infrastructure, and use Cisco DNA Center Assurance to find issues and optimize operations.
- Act as a pre-sales technical advisor, running consultations, proposals, product demos and proof-of-concept testing alongside the sales team.
- Lead technical response during organization-wide outages, and author design and configuration documentation.
Staff Network Operations Engineer
GE Digital · Alpharetta, GA
- Led Digital Operations Center shifts as team lead, driving fast, coordinated response to incidents across GE businesses.
- Troubleshot Layer 2/Layer 3 Cisco infrastructure across GE business units during major outages.
- Diagnosed and restored Cisco ASA VPN tunnels between corporate and third-party providers.
- Coordinated multiple technology groups on business-wide issues, and reviewed change history on critical tickets to cut troubleshooting time and prevent repeat incidents.
- Brought critical ERP applications onto the monitoring platform with application owners and software teams, and ran incidents, changes and root cause analysis in ServiceNow.
Network Engineer II
Trextel · Duluth, GA
Promoted from Staging Engineer
- Led the NOC for managed-services clients across 200+ sites, providing tier 3 support and training the NOC team.
- Built network automation with Python and Expect.
- Configured site-to-site VPNs on Cisco ASA, Fortinet FortiGate and Dell SonicWall, and hardened internet-facing firewalls and routers with access control lists.
- Deployed TACACS+ servers on Windows and Linux for secure AAA device access.
- Configured Cisco, Fortinet and Adtran routers and switches to client requirements, and designed and maintained the corporate network.
- Built lab environments to test routing protocols and security designs, designed wireless networks with Aerohive HiveManager, and set up SolarWinds monitoring.
- As Staging Engineer, managed network and VoIP rollouts across 300+ locations nationwide.
NOC Engineer
Conquest Technologies · Columbia, MD
- Deployed access points with Cisco Flex 7500 wireless controllers, pushing configurations through Cisco Prime.
- Verified OSPF and BGP route propagation to remote sites, and configured and troubleshot Cisco switch stacks.
- Configured ACLs and VPNs on Cisco ASA firewalls.
- Ran failover testing to keep client sites up, and coordinated multi-time-zone deployments with on-site field technicians.
Staging Coordinator & Systems Administrator
AUS Information Systems · Duluth, GA
- Configured and staged Cisco, Fortinet and AT&T NetGate network equipment for client deployments nationwide.
- Supported field technicians with installation and configuration troubleshooting, and scheduled installs across the U.S.
- Administered Active Directory and the company's network, servers and computing environment.
03 / Credentials
Certifications & education
Cisco certifications and a business degree in computer information systems.
CCNP
CCNP Routing & SwitchingCisco Certified Network Professional
SEC
CCNA SecurityCisco Certified Network Associate, Security
CCNA
CCNACisco Certified Network Associate
BBA, Computer Information Systems
Georgia State University
J. Mack Robinson College of Business
04 / Contact
Let's build something secure.
Open to conversations about network architecture, security and automation work.