Available for Freelance Consulting

Gabriel
Castro

_

I empower ISPs and Enterprises by resolving complex routing issues, designing high-availability architectures, and eliminating manual overhead through Python and AI-driven automation. Precision, zero downtime, and scalable results.

10+
Yrs. Expertise
CCNP
18
Badges
6+
Enterprise Clients
Gabriel Castro

// Companies & Projects I’ve Supported

// What I Can Do For You

Specialized Services

I work as an independent consultant delivering high-impact network and infrastructure solutions. Every engagement is focused on one thing: solving your problem fast, with zero guesswork.

🔌

Network Architecture & Design

Designing scalable, high-availability networks (BGP, OSPF, Datacenter, Azure Cloud) tailored to your specific business needs and growth projections.

BGP / OSPFDatacenterAzure CloudSP Core
💻

Infrastructure Automation

Eliminating manual tasks and human error through custom Python scripting and API integrations, saving your engineering team hundreds of hours a month.

PythonNetmikoAPI IntegrationCI/CD
🔍

Advanced Troubleshooting & Audits

Rapid identification and resolution of complex routing and switching bottlenecks in Service Provider and Enterprise environments to ensure stability.

L3/L4 SupportIOS-XREVPN/VXLANRoot Cause
🤖

AI Integration in Operations

Deploying custom AI tools—such as RAG-based systems for log analysis—to modernize your network operations and accelerate incident resolution.

RAG SystemsLLMLog AnalysisAutomation

Ready to solve your network challenge?

Every project starts with a free 30-minute technical call. No sales pitch — just an honest assessment of what you need.

// 01. About Me

Who I Am

I am an Independent Telecommunications Engineer and Consultant with over a decade of experience specializing in Service Provider and Datacenter networking. My technical core lies in IOS-XR (Cisco 8000, NCS5500), BGP, OSPF, Segment Routing, EVPN/VXLAN, and Python automation.

I bring a methodical, investigative approach to network problems — I don’t stop until the root cause is isolated. Whether it is troubleshooting a complex BGP policy anomaly or diagnosing a fabric-level hardware fault, I apply the same analytical depth to ensure zero downtime.

Throughout my career, I have led critical infrastructure projects for global industry leaders, including Cisco, Microsoft, NBC Universal, and major telecom operators across the Americas. I hold 3× CCNP (Enterprise, Service Provider, Data Center), alongside CCNA, DevNet Associate, and AWS Technical accreditations.

Available for freelance consulting in network design, IOS-XR troubleshooting, SP/DC architecture, and Python automation. Based in Mexico City, I operate remote-first worldwide. With valid US and Australian visas, I am also fully equipped for international on-site engagements when required.

Core Networking
IOS-XR / XR7 / eXR
BGP / OSPF / ISIS
Segment Routing
MPLS / L2VPN / XCONNECT
EVPN / VXLAN
BFD / VRRP / HSRP
Platforms
Cisco 8000 / Spitfire
NCS5500 / NCS5504
Nexus 9K / NXOS
SONiC
ASR920 / NCS5508
Catalyst 9K
Automation & Cloud
Python / Netmiko
Network Automation
AWS / Cloud Infra
Microsoft Azure
Languages
Spanish — Native
English — Professional
// 03. Featured Projects

Case Studies

Real-world engagements. Problem → Solution → Result.

Zero-Downtime Core Migration — Microsoft Azure DC
■ Problem

Global Azure datacenter fabric required IOS-XR platform upgrades and 8818 Fabric Card replacements across 7 sites with no tolerance for service interruption.

■ Solution

Designed phased MOP per-site with rollback procedures, pre/post validation scripts in Python, and coordinated execution windows with Microsoft NOC teams.

■ Result

100% of upgrades completed with zero unplanned downtime across Phoenix, Chicago, Des Moines, San Jose, Campinas, and Querétaro sites.

IOS-XRCisco 8000NCS5500Python
VXLAN Fabric Migration — NBC Universal Hollywood
■ Problem

NBC Universal required a full EVPN/VXLAN migration of their Hollywood datacenter fabric with strict broadcast windows and complex legacy dependencies.

■ Solution

Created detailed MOP documentation for Nexus platform migration, covering pre-migration validation, cutover steps, and full rollback procedures for each segment.

■ Result

Migration executed on schedule within planned maintenance window with all legacy services verified operational post-cutover.

EVPN/VXLANNexus 9KNXOSMOP Design
Network Automation Framework — Upgrade Validation
■ Problem

Manual pre/post upgrade validation across NCS5500 fleet was time-consuming and error-prone, requiring engineers to check hundreds of state parameters per device.

■ Solution

Developed Python automation framework using Netmiko with auto-discovery of OSPF/BGP/ISIS processes, config capture/restore, and device-agnostic JSON config.

■ Result

40% reduction in upgrade validation time. Consistent, repeatable process across all NCS5504/5508 platforms with full audit trail.

PythonNetmikoNCS5500Automation
// 02. Experience & Key Achievements

Track Record

// All companies & clients
2024 — Present · Global / Remote
Freelance Network & Automation Consultant
Independent
Partnering with enterprises to optimize network architectures and implement zero-downtime migrations.
Developing tailored Python scripts that reduce operational deployment times by over 40%.
Providing on-demand Level 3/4 support and architectural audits for complex Service Provider environments.
PythonNetwork DesignSP/DCIOS-XRZero-Downtime
Jan 2023 – Present · Mexico City (Remote)
Senior Network Consulting Engineer · Tech Lead AT&T Mexico
Cisco Systems · 7 years
Led vulnerability remediation across 7 global Azure datacenters (US, BR, MX) — zero service impact
Delivered VXLAN migration MOP for NBC Universal Hollywood on Nexus platforms
Built Python automation framework reducing upgrade validation time by 40%
Executed 8818 Fabric Card replacements + IOS-XR upgrades across NCS5500/Cisco 8000 fleet
IOS-XRCisco 8000NCS5500VXLANAzure CAPPythonSmart Licensing
Sep 2019 – Dec 2022 · México · 3 yrs 4 mos
Network Consulting Engineer
Cisco Systems · Total: 7 yrs (2019–Present)
Tech Lead for AT&T Mexico — SP and enterprise consulting for AT&T, Telmex, and Axtel
Designed and validated BGP, Segment Routing, MPLS XCONNECT topologies in production environments
Executed protocol failover validation (VRRP, HSRP, EVPN) with zero unplanned downtime
BGPOSPFSegment RoutingMPLSEVPNGRE
Aug 2016 – Sep 2019 · CDMX · 3 yrs 2 mos
Network Support Engineer
Totalplay Empresarial
Executed last-mile migrations for enterprise accounts including TV Azteca
Multi-vendor environment: Cisco, HP Comware, 3COM — end-to-end provisioning and validation
Cisco IOSHP ComwareLast MileEnterprise Edge
Dec 2015 – Mar 2016 · México · 4 mos
Drive Test Engineer
LCC – A Tech Mahindra Company
GSM/UMTS drive test campaigns for Telcel across Mexico City — signal quality benchmarking
GSMUMTSDrive TestHuawei
Sep 2015 – Dec 2015 · Caracas, Venezuela · 4 mos
Telecom Specialist
Telefónica
E1 circuit migrations for legacy radio decommissioning at Telefónica Mexico
Microwave link verification across multiple vendors + NodeB UMTS / GSM BTS monitoring
TDM / E1MicrowaveGSM / UMTSNodeB
// 03. Certifications

Credentials & Badges

// Badge Gallery — Issued to Gabriel Castro
// 04. Global Footprint

Global Impact

// Blue pins = Microsoft Azure Datacenter deployments · Cyan pins = On-site project locations

Azure Datacenter Deployments

// Replace + with your datacenter photos

On-Site Project Locations

// Replace + with your travel photos

// 05. Contact

Start Your Project

01
Discovery Call (15 min)
We align on your current network challenges, scope, and timeline.
02
Architecture & Proposal
I design a custom plan, technical scope, and clear timeline for your project.
03
Execution & Support
Seamless implementation with clear communication and full documentation.

Available for freelance engagements worldwide. Based in Mexico City — remote-first, on-site when needed. Permanent resident of Mexico. Tourist visas: USA & Australia.

✓ Message sent! I will get back to you within 24 hours.
// 06. Gabriel & AI

Powered by AI

Pre-ChatGPT Adopter
Prompt Engineering
AI Automation
Cisco AI Certified
🧠

Early Adopter & Deep Practitioner

Gabriel has been studying, experimenting, and applying AI technologies before ChatGPT became a household name. From early transformer architectures to modern LLMs, his understanding goes beyond surface-level — he grasps the underlying mechanics that make these systems work.

This depth allows him to leverage AI in ways most engineers cannot: not just using tools, but designing systems around them to solve real engineering problems.

Prompt Engineering Expert

Gabriel specializes in advanced prompt engineering — crafting precise, structured prompts that unlock the full potential of AI models for complex engineering tasks:

  • Automate network documentation & MOP generation
  • AI-assisted IOS-XR troubleshooting workflows
  • Accelerate Python development with AI pair programming
  • Synthesize technical reports from raw network data
🤖

AI + Networking: A Unique Edge

The combination of 10+ years of deep networking expertise with advanced AI skills creates a truly unique profile — intelligent systems tailored to SP and datacenter environments.

  • RAG-based IOS-XR troubleshooting assistant (in development)
  • AI-driven upgrade test matrix automation
  • LLM-powered network change validation
  • Intelligent log analysis & anomaly detection
🌟

Tools & Stack

Claude (Anthropic) ChatGPT / GPT-4 GitHub Copilot Gemini LangChain RAG Systems Python AI APIs Vector DBs Prompt Design Fine-tuning Concepts