📚 Abstraction Layers

The “eras” of IT — the vertical axis that runs through every domain.

OSI / network layers

L2 — Ethernet, VLAN, MAC, 802.1X, STP
L3 — IP, routing, OSPF, BGP, VPC/VNet routing
L4 — TCP/UDP, load balancers (NLB/Azure LB), firewalls
L7 — HTTP, TLS, ALB/App Gateway, service mesh, WAF

Cloud service models

IaaS — EC2, VMs, raw networks
PaaS — App Service, ECS, managed DBs
SaaS — finished products consumed over the network

All layer notes

TABLE WITHOUT ID file.link AS "Note", type AS "Type"
FROM "12 - Layers"
WHERE type != "moc"
SORT file.name ASC