Network Infrastructure

RADIUS is the AAA protocol behind every enterprise Wi-Fi login, VPN authentication, and 802.1X deployment. FreeRADIUS, Cisco ISE, and Aruba ClearPass all implement it. Essential for understanding corporate network access and SSO integration.

BGP stitches the internet together — every AS, CDN, cloud provider, and multi-homed network runs it. Understanding AS path, communities, and prefix aggregation is essential for cloud networking, CDN design, and any serious network engineering role.

SNMP remains the universal monitoring protocol for network equipment: routers, switches, UPS, servers. Every NOC and network monitoring tool (Zabbix, Nagios, LibreNMS) speaks SNMP. Understanding OID trees, MIB compilation, and USM vs community strings is essential for network operations.

NETCONF replaced manual CLI for network device configuration in most modern SD-WAN, carrier, and enterprise deployments. Understanding datastores, capabilities, and YANG-driven RPC is essential for network automation.

YANG is to NETCONF what JSON Schema is to REST APIs — it describes the data model. Any network automation work with modern devices (Juniper, Cisco IOS-XR, Nokia SR-OS) requires reading and writing YANG models.

RESTCONF brings network device management to the HTTP/JSON world. Most modern network OSes (Cisco IOS-XE 16.6+, Junos 17.3+, Nokia SR-OS) support it. If you prefer REST over SSH/XML for network automation, this is your interface.

Diameter is the AAA backbone of LTE and IMS networks. If you build carrier infrastructure or work on 4G/5G billing and policy enforcement, you'll encounter Diameter on the S6a, Rx, Gx, and Gy interfaces.

TACACS+ is the standard for managing network infrastructure logins. Cisco, Juniper, and Aruba devices all support it. Any NOC that uses TACACS+ via Cisco ISE or Tac_Plus needs engineers who understand the AAA separation model.

gNMI is replacing SNMP for modern network monitoring: lower latency, higher efficiency, native streaming telemetry. Arista, Cisco (IOS-XR, IOS-XE), Juniper, and Nokia all support gNMI. Key for network observability pipelines (Telegraf, gnmic).

OSPF is the interior routing protocol of choice for enterprise and carrier networks. Understanding area design, LSA types, and SPF convergence is essential for data center networking, WAN design, and network certification paths.

MPLS is the forwarding substrate of carrier networks, MPLS VPNs, and traditional WAN services. Understanding FEC, LDP, and LSP concepts is essential for service provider or enterprise WAN networking.

SR is replacing RSVP-TE and MPLS LDP in modern SD-WAN, 5G transport, and hyper-scale DC networks. Cisco, Juniper, Nokia, and Arista have all standardized on it. Essential for modern network engineering.

BFD is how networks achieve sub-second failover — without it, BGP takes 90+ seconds to detect a peer failure. Any high-availability design (active-active DC, SD-WAN, carrier) relies on BFD for fast convergence.

OSPFv3 is required for IPv6 network deployments. If you're dual-stacking or going IPv6-only, you'll need OSPFv3 alongside or replacing OSPFv2.

IS-IS is the IGP of choice in most Tier-1 and Tier-2 carrier networks and large-scale DC fabrics (Meta, Amazon). It runs under BGP in many hyperscale designs. Essential for service provider and large-scale DC networking roles.

EVPN-VXLAN is the fabric technology in modern hyperscale and enterprise data centers. Arista, Cisco (ACI), and Juniper (QFX) use it. Understanding MAC/IP type-2 routes and ARP suppression is key for data center network engineering.