Lab 15 — EIGRP Named Mode — Wide Metrics and Address Families

Active Nodes

Active routers: HUB-WC-1, HUB-WC-2, SPK-WC-1, SPK-WC-2, SPK-WC-3

Key Concepts

EIGRP Named Mode Architecture

Named mode replaces the classic router eigrp AS with router eigrp NAME containing address-family sub-configurations. This allows multiple address families (IPv4, IPv6) under one EIGRP process with consistent configuration structure. The address-family section specifies the autonomous-system number, network statements, and all interface-level parameters. Unlike classic mode where eigrp stub applied to all AFs, named mode controls stub per address-family independently.

Wide Metrics (64-bit)

Classic EIGRP metrics use 32-bit values, causing metric ceiling issues on interfaces faster than ~128 Gbps. Named mode introduces 64-bit "wide metrics" that scale to Tbps interfaces. Wide metrics also add a new latency component (in picoseconds). The composite metric formula changes: Metric = [(K1×BW + K3×Delay) / RIB-scale × RIB-multiplier]. Classic compatibility mode (EIGRP classic metric) is automatically used when a named-mode router peers with a classic-mode router — verify with show ip eigrp neighbors detail | include Metric.

Per-AF Interface Tuning

Named mode allows different parameters per address family per interface. A DMVPN spoke can have IPv4 summarization toward the hub while running IPv6 without summarization. The af-interface hierarchy: global defaults under af-interface default, overridden per-interface with af-interface TunnelX. Authentication, hello timers, stub behavior, and bandwidth-percent are all configurable independently per AF.

Named Mode Configuration

HUB-WC-1EIGRP named mode — IPv4 + IPv6 AF

router eigrp DMVPN-FABRIC
 !
 address-family ipv4 unicast autonomous-system 100
  !
  af-interface default
   passive-interface
  !
  af-interface Tunnel0
   authentication mode md5
   authentication key-chain DMVPN-AUTH
   bandwidth-percent 50
   hello-interval 20
   hold-time 60
   no passive-interface
   no split-horizon
  !
  topology base
   redistribute connected metric 10000 100 255 1 1500
  !
  network 10.255.4.1 0.0.0.0
  network 172.16.10.0 0.0.0.255
  eigrp router-id 10.255.4.1
 exit-address-family
 !
 address-family ipv6 unicast autonomous-system 100
  !
  af-interface Tunnel0
   authentication mode md5
   authentication key-chain DMVPN-AUTH
   no passive-interface
   no split-horizon
  !
  topology base
  !
  eigrp router-id 10.255.4.1
 exit-address-family

Verification

show ip eigrp topology all-links

Expected: All successor and feasible successor routes shown. Wide metrics in Delay column (picoseconds for named mode).

show eigrp address-family ipv4 neighbors

Expected: Named-mode specific output format. Address family "IPv4 Unicast" listed. Peers show Hold timer and Q count.

show eigrp address-family ipv6 neighbors

Expected: IPv6 EIGRP neighbors listed with link-local neighbor addresses on Tunnel0 interface.

Research and direction by Ioannis (John) Konstas; compiled and finalized with AI assistance.