CCIE EI v1.1 – Mastering EIGRP

Learn over-the-top routing in named mode EIGRP, achieving end-to-end reachability across WANs with Lisp encapsulation, edge route reflectors, and reachability between customer and provider edges.

Explain eigrp path selection using reported distance, feasible distance, and composite metric from vector metrics; identify successors and feasible successors; enable equal-cost load sharing and variance for multiple paths.

Explore the classic EIGRP metric and its composite formula, focusing on bandwidth and delay with K-1 and K-3, and how GAAP configuration defaults this calculation.

Compute the wide metric by combining throughput and latency in EIGRP, using bandwidth and delay constants; explore metric ribbs scale and 64‑bit versus 32‑bit metrics in routing and adjacency.

Learn how to view and configure EIGRP timers, including hello interval and hold-down time, with named and classic modes, using the ip hello interval and ip hold down time commands.

Configure a default route in EIGRP by either redistributing a static default route or using an interface/address-family summary. Compare classic and named modes for IPv4 and IPv6, preserving existing routes.

Understand how an EIGRP router becomes stuck in active when no feasible successor exists, triggering multicast queries and SAA replies to verify reachability and prevent adjacency drops.

Enable EIGRP graceful shutdown to notify neighbors during maintenance, allowing rerouting via alternative paths and avoiding long disruptions from reboot or hold-down times.

Configure EIGRP stub routing to suppress queries from neighbors. Explore options such as receive only, connected, summary, static, and redistribution, plus the role of leak maps.

Apply leak maps in EIGRP to leak specific prefixes from a summary or stub routing, using route maps and ACL to advertise chosen prefixes while preserving a summarized route.

Learn how EIGRP enables equal-cost load balancing by adding multiple next hops to the routing table, using feasible distance and variance to achieve balanced paths.

Explore add-path in EIGRP for hub-and-spoke DMVPN topologies, enabling up to four equal-cost next hops to the same prefix and guiding migration from classic to named mode.

Explore how EIGRP address families work in named mode, enabling IPv4 and IPv6 unicast by default, when to use multicast, and how to redistribute connected routes under the address family.

Explore fast reroute in EIGRP, precomputing loop-free alternatives (LFAs) and feasible successors with feasible distances to instantly switch traffic on link failure, using vector metrics.

Learn how VRF lite isolates department data with virtual routing tables, enabling IPv4 and IPv6 networks, route distinguishers, and controlled route leaking.

Learn how EIGRP uses hop count in a distance vector protocol to filter edge routes by maximum hops, and observe routes drop as you lower the limit.

Apply offset lists to EIGRP metrics with an ACL in in or out direction, adding values to the metric to influence rib and typology table, enabling equal-cost paths.

Learn to filter EIGRP routes with distribute lists in inbound and outbound directions, using gateway options, prefix lists, named ACLs, and route maps.