Networks
Protocol-oriented technical knowledge: fundamentals, switching, IP, routing, services, security, VPNs, service-provider technologies, wireless and evidence-driven troubleshooting.
Topics by protocol and technology
Networking Fundamentals
Core concepts for understanding communication, protocols, devices, encapsulation and data flow.
Open topic →OSI and TCP/IP Models
Layers, responsibilities, PDUs, encapsulation and practical use of reference models during troubleshooting.
Open topic →Ethernet
IEEE 802.3 framing, MAC addressing, FCS, MTU, duplex, autonegotiation, copper, fiber and PHY behavior.
Open topic →Ethernet Switching
MAC learning, FDB/CAM, forwarding, filtering, flooding, loops and Layer 2 switching behavior.
Open topic →VLAN and IEEE 802.1Q
Layer 2 segmentation, access and trunk behavior, tagging, PVID/native VLAN, allowed VLANs and troubleshooting.
Open topic →STP, RSTP and MSTP
Loop prevention, root election, port roles/states, rapid convergence, MST regions and Layer 2 protections.
Open topic →LACP and Link Aggregation
IEEE 802.1AX link aggregation, member selection, hashing, resiliency and troubleshooting.
Open topic →QinQ and VLAN Tunneling
Provider Bridging, S-TAG/C-TAG, double tagging, MTU and Metro Ethernet service transport.
Open topic →Inter-VLAN Routing
Layer 3 communication between VLANs using routed interfaces, SVIs or router-on-a-stick designs.
Open topic →IPv4
IPv4 header, addressing, forwarding, TTL, MTU, fragmentation, RIB/FIB and longest-prefix match.
Open topic →Subnetting, CIDR and VLSM
IPv4 prefix calculation, VLSM, summarization and address-plan design.
Open topic →ARP
IPv4-to-MAC resolution, ARP cache, gratuitous ARP, proxy ARP, duplicate addressing and troubleshooting.
Open topic →ICMP, Ping and Traceroute
ICMP messages, reachability tests, TTL expiry, unreachable messages, PMTUD and diagnostic limitations.
Open topic →IPv6
IPv6 addressing, headers, extension headers, ICMPv6, SLAAC, DHCPv6, routing and dual-stack operation.
Open topic →IPv6 Neighbor Discovery
Neighbor Discovery, Router Solicitation/Advertisement, address resolution, DAD, SLAAC and operational security.
Open topic →IP Routing
RIB, FIB, next-hop resolution, route preference, metrics, ECMP and forwarding decisions.
Open topic →Static Routing
Static, default, floating and discard routes, recursive next-hop resolution and operational validation.
Open topic →OSPF
Link-state routing, adjacencies, LSDB, SPF, areas, LSAs, summarization, redistribution and troubleshooting.
Open topic →IS-IS
Link-state IGP operation, levels, adjacencies, LSPs, TLVs, SPF, IPv4/IPv6 and service-provider design.
Open topic →BGP
Interdomain routing, sessions, attributes, best-path selection, policy, filtering, communities and troubleshooting.
Open topic →RPKI and Route Origin Validation
Resource Public Key Infrastructure, ROAs, origin validation states and safer BGP routing policy.
Open topic →BFD
Fast failure detection independent of routing protocol, session states, timers and integration with routing.
Open topic →Policy-Based Routing
Policy routing by source, marks or alternate tables, multi-WAN design, failover and asymmetry troubleshooting.
Open topic →DHCP
Dynamic address assignment, DORA, leases, relay, options, DHCPv6 distinctions and troubleshooting.
Open topic →DNS
Name resolution, recursive and authoritative roles, records, delegation, caching, DNSSEC and troubleshooting.
Open topic →NAT and CGNAT
Address and port translation, state, source/destination NAT, CGNAT scaling and troubleshooting.
Open topic →IP Multicast
Multicast addressing, IGMP/MLD, PIM concepts, receiver membership, distribution trees and troubleshooting.
Open topic →Access Control Lists
Packet filtering logic, direction, ordering, stateful versus stateless behavior and safe validation.
Open topic →Firewall
Stateful filtering, zones/chains, connection tracking, policy design, logging and troubleshooting.
Open topic →Quality of Service
Classification, marking, DSCP, policing, shaping, queuing, scheduling and congestion management.
Open topic →GRE Tunneling
Generic Routing Encapsulation, tunnel endpoints, routing over tunnels, MTU overhead and troubleshooting.
Open topic →IPsec
IKE, Security Associations, ESP, transport/tunnel modes, policy, NAT traversal and VPN troubleshooting.
Open topic →WireGuard
Modern peer-based VPN operation, keys, AllowedIPs, endpoints, routing, firewall, MTU and troubleshooting.
Open topic →Network Troubleshooting Center
Evidence-driven diagnosis from physical layer to BGP: symptom, hypothesis, test, evidence, correction and validation.
Open topic →Networking Labs
Practical labs for switching, routing, services, VPNs and troubleshooting with repeatable validation.
Open topic →Networking Certifications
Study map relating networking topics to certification tracks without replacing official blueprints.
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