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Networking — Advanced Concepts & Protocols

Last reviewed: 2026-05-29

Networking encompasses the complex systems and protocols that enable communication across the internet, data centers, and enterprise environments. This training covers advanced networking topics beyond the fundamentals.

Overview

While the NETWORK.md file covers networking fundamentals (OSI model, IP addressing, basic protocols), this file focuses on more advanced networking concepts relevant to cloud infrastructure, DevOps, and systems engineering.

Training Content

  • VLANs and network segmentation
  • Routing protocols (OSPF, BGP)
  • Network Address Translation (NAT) and PAT
  • VPN technologies (IPsec, WireGuard, OpenVPN)
  • Software-Defined Networking (SDN)
  • Network monitoring and observability
  • Performance tuning (TCP window scaling, congestion control)
  • MTU, Jumbo Frames, and Path MTU Discovery

Advanced Topics

Virtual Networking

  • VLANs (802.1Q) — Segment networks at Layer 2 without separate switches
  • VXLAN — Overlay networks that extend L2 segments over L3 networks (used in cloud/DC)
  • VRF — Virtual Routing and Forwarding (multiple routing tables on one router)
  • VPN — Secure tunnels over untrusted networks (site-to-site, remote access)

Routing Protocols

Protocol Type Use Case
OSPF Link-state IGP Enterprise/internal routing
BGP Path-vector EGP Internet routing, multi-cloud networking
RIP Distance-vector IGP Legacy, small networks
IS-IS Link-state IGP ISP backbones

Load Balancing

Type Layer Description
DNS LB Application Distributes based on DNS resolution
L4 LB Transport Forwards TCP/UDP without inspecting content
L7 LB Application Terminates HTTP, inspects requests (HAProxy, Nginx)

Network Security

  • NACLs — Stateless network access control lists
  • Security Groups — Stateful firewall at instance level (AWS terminology)
  • Egress filtering — Control outbound traffic
  • Ingress filtering — Control inbound traffic
  • Network segmentation — DMZ, management, production subnets

Practical Network Troubleshooting

# Check routing table
ip route show          # Linux
route -n               # Legacy
netstat -rn

# Check ARP cache
ip neigh show

# Test MTU discovery
ping -M do -s 1472 google.com   # Don't fragment (find max MTU)

# Check DNS resolution speed
dig +stats google.com

# TCP connection test
nc -zv host 443       # Check port reachability

Measuring Network Performance

Metric Description Good Value
Latency Round-trip time (RTT) <1 ms (local), <50 ms (inter-DC)
Jitter Variation in latency <5 ms
Packet Loss % of packets dropped <0.1%
Throughput Actual data transfer rate Depends on link capacity
Bandwidth Maximum theoretical rate 1 Gbps, 10 Gbps, 100 Gbps

Cloud Networking

Concept AWS GCP Azure
VPC VPC VPC Virtual Network
Subnet Subnet Subnet Subnet
Firewall Security Groups / NACLs Firewall Rules NSG
Load Balancer ALB / NLB GLB / L4 App Gateway / ILB
VPN Site-to-Site VPN Cloud VPN VPN Gateway
DNS Route 53 Cloud DNS Azure DNS
CDN CloudFront Cloud CDN Azure CDN

Resources