← Consultant · Learner

Knowledge material · ~6 min read

Consultant · Learner

Cloud, virtualization, and routing become physical to you.

Overview

Consultants stop treating networks and clouds as 'someone else's problem'. You segment with VLANs, design Wi-Fi that doesn't drop calls, and read an Azure bill without flinching. You learn the abstractions: a VM (Virtual Machine) is a file, a subnet is a contract, a region is a fault boundary.

VLANs & inter-VLAN (Virtual Local Area Network) routing

  • ▸Access port = one VLAN, untagged. Trunk port = many VLANs, tagged (802.1Q).
  • ▸Native VLAN should not be VLAN 1 in production.
  • ▸Inter-VLAN routing on an L3 switch (SVI) or via firewall ('router on a stick').
  • ▸Segment by trust: corp, IoT, guest, voice, mgmt.

Wi-Fi reality

  • ▸2.4 GHz: 3 non-overlapping channels (1/6/11), longer reach, more noise.
  • ▸5 GHz / 6 GHz: more channels, more bandwidth, shorter reach.
  • ▸Plan for -67 dBm coverage for voice, -70 dBm for data.
  • ▸Roaming requires overlap, matched SSIDs, and 802.11k/v/r.

Azure fundamentals

  • ▸Tenant → Management Group → Subscription → Resource Group → Resource.
  • ▸Regions are billing & latency boundaries; AZs are fault boundaries inside.
  • ▸RBAC (Role-Based Access Control) at any scope; inheritance flows down.
  • ▸Tags drive cost reports — enforce with policy, not goodwill.

Virtualization basics

Hyper-V and VMware both abstract CPU (Central Processing Unit)/RAM (Random Access Memory)/disk/NIC (Network Interface Card) into a VM. Watch the host: CPU ready time, memory ballooning, datastore latency. Snapshots are not backups — they grow, they slow, they fail at exactly the worst time.

Glossary

VLAN
Virtual LAN (Local Area Network) — L2 segmentation tagged 1–4094.
SVI
Switched Virtual Interface — gateway IP (Internet Protocol) on an L3 switch.
Resource Group
Azure container; lifecycle and access boundary.
Snapshot
Point-in-time disk delta — short-lived only.

Common pitfalls

Practice drills