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Networking — Advanced Concepts & Protocols

Last reviewed: 2026-09-17

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

Overview

The Network — Infrastructure & Protocols page covers networking fundamentals (OSI model, IP addressing, basic protocols); this article focuses on more advanced networking concepts relevant to cloud infrastructure, DevOps, and systems engineering.

Topics Covered

  • 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

To-do

Status: incomplete. Still to write:

  • Write the NAT/PAT section promised in Topics Covered (static/dynamic NAT, PAT/overload, port forwarding) — there is no NAT content in the body.
  • Write the VPN technologies section (IPsec, WireGuard, OpenVPN; site-to-site vs remote access) — currently a single bullet under Virtual Networking.
  • Write the Software-Defined Networking section (control plane vs data plane, OpenFlow/OVS, controllers) promised in Topics Covered.
  • Write the network monitoring and observability section promised in Topics Covered.
  • Write the performance-tuning section: TCP window scaling, congestion-control algorithms, plus MTU/jumbo frames/path MTU discovery — currently only a ping -M do line in the troubleshooting block.