EIGRP

Enhanced Interior Gateway Routing Protocol, Cisco's hybrid distance-vector IGP. Articles tagged EIGRP cover the DUAL algorithm, composite metric and K values, stub routing, adjacency requirements, and Cisco IOS XE configuration.

7 posts

EIGRP

EIGRP Neighbor Requirements: The 5 Things That Must Match

The 5 things that must match for EIGRP routers to become neighbors: subnet, AS number, K-values, authentication, and process membership. Plus what does NOT need to match.

Jun 12, 2026 5 min read

GRE

Routing Protocols Over GRE: OSPF, EIGRP, BGP

Run OSPF, EIGRP, and BGP across GRE tunnels on Cisco IOS XE. Recursive routing fix, OSPF network types, EIGRP metric tuning, and BGP update-source.

May 1, 2026 8 min read

EIGRP

EIGRP Stub Routing for Hub-and-Spoke

EIGRP stub routing makes hub-and-spoke topologies scale. The five stub options, query suppression, DMVPN integration, and the production patterns for branch deployments.

Apr 26, 2026 5 min read

EIGRP

EIGRP vs OSPF: When to Use Each

EIGRP vs OSPF in 2026. The technical differences, the convergence story, vendor reality (EIGRP is still Cisco-only in practice), and the design implications for new vs existing networks.

Apr 26, 2026 5 min read

EIGRP

EIGRP Configuration on Cisco IOS XE: Classic and Named Mode

EIGRP configuration on Cisco IOS XE: classic mode, named mode, network statements, passive-interface default, summarization, HMAC-SHA-256 authentication, and the production template.

Apr 26, 2026 6 min read

EIGRP

EIGRP Metric and K Values Explained

The EIGRP composite metric formula, the five K values and why never to change them, the 64-bit wide metric for modern interfaces, and how to verify metrics in show output.

Apr 26, 2026 5 min read