IPv6 Header Format Explained
The IPv6 header byte by byte: 40 bytes fixed, 8 fields, extension headers, Next Header chaining, comparison to IPv4, and what it looks like in Wireshark.
Go Deeper on Enterprise Networking
In-depth tutorials on OSPF, BGP, 802.1X, and more- for engineers who want to understand the why, not just the how.
OSPF
Open Shortest Path First tutorials covering LSA types, area design, neighbor states, route summarization, authentication, and OSPF tuning for enterprise and service provider networks.
33 posts
BGP
Border Gateway Protocol tutorials covering eBGP, iBGP, path selection, route filtering, communities, and BGP design for enterprise and service provider networks.
34 posts
802.1X
802.1X port-based network access control tutorials covering EAP methods, RADIUS integration, MAB, dynamic VLAN assignment, and Cisco ISE deployment for wired and wireless environments.
32 posts
VLAN
VLAN tutorials covering VLAN creation, 802.1Q trunking, inter-VLAN routing, VTP, private VLANs, and VLAN design for enterprise campus and data center switching environments.
25 posts
Wireless
Wireless networking tutorials covering 802.11 standards, Wi-Fi 6/6E/7, RF fundamentals, WLAN design, roaming, security, and Cisco Catalyst 9800 wireless LAN controller configuration for enterprise Wi-Fi deployments.
45 posts
STP
Spanning Tree Protocol tutorials covering classic STP, RSTP, and MSTP operation, port roles and states, PortFast, BPDU Guard, root bridge election, and loop prevention in switched networks.
27 posts
Latest posts
IPv6 Configuration on Cisco IOS XE
IPv6 configuration on Cisco IOS XE: enabling IPv6, static and SLAAC addresses, RA options, OSPFv3, BGP for IPv6, EIGRP for IPv6, VRRPv3, dual-stack, and first-hop security.
IPv6 Address Types: Link-Local, Global, Unique Local
The six IPv6 address types: global unicast, link-local, ULA, multicast, anycast, and special. Prefixes, scope, when to use which, and design implications.
IPv4 vs IPv6: The Real Differences
IPv4 vs IPv6 in 2026. Header differences, ARP vs Neighbor Discovery, SLAAC vs DHCP, NAT vs end-to-end, and dual-stack as the migration reality.
IPv6 Address Format Explained Byte by Byte
IPv6 addresses are 128 bits as eight groups of four hex digits. The two compression rules, prefix notation, EUI-64 interface IDs, special addresses, and worked examples.
HSRP vs VRRP vs GLBP: Choosing the Right FHRP
HSRP, VRRP, and GLBP all solve first-hop redundancy with different trade-offs. The side-by-side comparison, when each wins, failover times, and migration paths.
GLBP for Active/Active Load Balancing
GLBP (Gateway Load Balancing Protocol) is Cisco's load-balancing FHRP. AVG, AVFs, three load balancing methods, configuration, and when GLBP is actually the right answer.
VRRP Explained: The Vendor-Neutral FHRP
VRRP (Virtual Router Redundancy Protocol, RFC 5798) is the vendor-neutral FHRP. How it works, master election, IP address owner trap, vs HSRP, Cisco IOS XE configuration, and tracking.
Cisco MPLS Configuration on IOS XE
Cisco MPLS configuration on IOS XE: enabling MPLS forwarding, LDP, LDP-IGP sync, VRFs for L3VPN, and MP-BGP between PEs. With a complete PE config example.
MPLS L3VPN with MP-BGP and VPNv4
MPLS L3VPN architecture: VRFs, Route Distinguishers, Route Targets, MP-BGP for VPNv4, the two-label stack, PE-CE routing, and the Cisco IOS XE configuration.
LDP and MPLS Label Distribution
LDP (Label Distribution Protocol) distributes MPLS labels across the network. Discovery, session establishment, distribution and retention modes, LDP-IGP sync, and Cisco IOS XE configuration.
MPLS Labels Explained: Format, Stacking, and Penultimate Hop Popping
MPLS labels byte-by-byte: 20-bit label, EXP/TC, S bit, TTL. The label stack model, reserved labels, Penultimate Hop Popping, TTL handling, and what labels look like in Wireshark.