Network Backbone Architect

When NOT to Use

• REST/GraphQL, ESB, or enterprise application integration design → enterprise-integration-api-developer
• Cloud Well-Architected, landing zone, and managed VPC/service selection → cloud-architect, enterprise-cloud-architect
• Day-two cloud resource configuration (subnets, LB, managed VPN to cloud) → cloud-engineer
• Cloud security guardrails, CSPM, and cloud IAM as primary deliverable → cloud-security-engineer
• Host firewall, endpoint, and corporate security control catalog → information-security-engineer
• OS patching, VM admin, and cloud instance operations → cloud-system-administrator
• Terraform modules, CI/CD, and K8s platform delivery without backbone routing design → infrastructure-engineer
• SLO programs, on-call, and incident response as the main task → site-reliability-engineer
• Cross-domain system ADRs unrelated to routing → senior-system-architecture
• Application throughput, caching, and horizontal scale without L3 design → high-concurrency-scalability
• Event bus and messaging topology only → event-driven-architecture
• OT/ICS segmentation, Purdue model, and plant protocols → scada-ics-cyber-security-specialist

Related skills

Core Workflows

1. Scope, constraints, and design principles

Clarify scale (sites, regions, carriers), traffic matrix, RTO/RPO for paths, and regulatory or sovereignty constraints.

See references/networkbackbonearchitect_scope.md.

2. Topology, hierarchy, and addressing

Define core/distribution/edge roles, summarization boundaries, and IP/VLAN/VRF plan.

See references/topologyhierarchyand_addressing.md.

3. Routing protocols and policy

Select IGP (OSPF, IS-IS) and BGP design—peering, communities, path selection, and filtering.

See references/routingigpbgpandpolicy.md.

4. WAN, MPLS, and SD-WAN

Architect carrier services, underlay/overlay, hub-spoke vs full mesh, and SLA alignment.

See references/wanmplssdwanandcarriers.md.

5. DCI, peering, and internet edge

Design data center interconnect, IX/transit/peering, and anycast or multi-homing at the edge.

See references/dcipeeringandinternetedge.md.

6. Resilience, QoS, capacity, and operations

Plan redundancy, BFD/FRR, backbone QoS, link sizing, change windows, and observability.

See references/resilienceqoscapacity_operations.md.

Outputs

• Backbone context — sites, traffic matrix, critical flows, and failure domains
• Logical topology — hierarchy, VRFs, summarization points, and DCI attachment
• Routing design — IGP areas/levels, BGP AS plan, policies, and community/tag semantics
• WAN/SD-WAN architecture — underlay, overlay, hub roles, and carrier map
• Internet edge brief — peering vs transit, IX placement, prefix origination, and filtering
• Resilience and QoS matrix — ECMP, BFD, FRR, DSCP classes, and maintenance domains
• Capacity model — link sizing assumptions, growth headroom, and trigger thresholds
• Observability plan — flow telemetry, SNMP/telemetry targets, and backbone dashboards

Principles

• Hierarchy before complexity — aggregate at core; keep edge policies simple
• Explicit failure domains — maintenance windows and blast radius per region or plane
• Policy at the edge — filter and tag at borders; keep core transit predictable
• Measure before oversizing — size links from busy-hour matrices and growth, not peak anecdotes
• Prefer L3 DCI — stretch L2 only with documented operational cost and risk
• Document one-way doors — ASN allocation, summarization boundaries, and peering contracts