Hands-On Lab: Configuring Redistribution Between OSPF and EIGRP

Lab Objective

Configure a boundary router running both OSPF and EIGRP to redistribute routes from each protocol into the other, verify routes appear correctly on both sides with the expected administrative distance, and confirm the seed metric each protocol requires for redistributed routes is properly applied.

Lab Purpose

Every routing protocol lab throughout this series operated within a single protocol domain. Real networks frequently run multiple protocols simultaneously — during a migration, after a merger, or due to vendor requirements — and redistribution is the mechanism that shares routes between these otherwise-isolated routing domains.

Lab Topology

OSPF Domain (Area 0)          EIGRP Domain (AS 100)
R1 ---- R2 (boundary) ---- R3

R1's LAN: 192.168.30.0/24 (OSPF)
R3's LAN: 192.168.40.0/24 (EIGRP)

R2 runs both OSPF (toward R1) and EIGRP
(toward R3)

Task 1: Verify Baseline Isolation Between Domains

Confirm R1 cannot see R3's LAN and vice versa before any redistribution is configured.

Task 2: Redistribute EIGRP Routes Into OSPF

On R2, redistribute EIGRP routes into OSPF, specifying an appropriate seed metric.

Task 3: Redistribute OSPF Routes Into EIGRP

On R2, redistribute OSPF routes into EIGRP, specifying EIGRP's required seed metric components.

Task 4: Verify R1 Learns R3's LAN via OSPF

Confirm R1 now sees R3's LAN as an OSPF external route.

Task 5: Verify R3 Learns R1's LAN via EIGRP

Confirm R3 now sees R1's LAN as an EIGRP external route.

Solution and Verification

R1# show ip route | include 192.168.40
-- (no output -- R3's LAN not yet visible)

R3# show ip route | include 192.168.30
-- (no output -- R1's LAN not yet visible)

R2(config)# router ospf 1
R2(config-router)# redistribute eigrp 100 metric-type 1 subnets

-- "subnets" is required for OSPF
-- redistribution to include any routes
-- more specific than a classful boundary
-- -- omitting it is a common mistake that
-- silently drops subnetted routes from
-- redistribution entirely

R2(config)# router eigrp 100
R2(config-router)# redistribute ospf 1 metric 10000 100 255 1 1500

-- EIGRP requires an explicit seed metric
-- with five components: bandwidth (kbps),
-- delay (10s of microseconds), reliability,
-- load, and MTU -- unlike OSPF's simpler
-- single metric value

R1# show ip route ospf

O E1  192.168.40.0/24 [110/20] via 10.1.1.2
-- R1 now sees R3's LAN as an OSPF External
-- Type 1 route, discussed earlier in this
-- series regarding OSPF external route types

R3# show ip route eigrp

D EX  192.168.30.0/24 [170/2681856] via 10.2.2.1
-- R3 sees R1's LAN as an EIGRP external
-- route (D EX), with administrative
-- distance 170 -- distinct from the 90
-- used for internally learned EIGRP
-- routes, reflecting the lower trust
-- typically given to redistributed routes

R1# ping 192.168.40.1

!!!!!
Success rate is 100 percent (5/5)

R3# ping 192.168.30.1

!!!!!
Success rate is 100 percent (5/5)
-- Full bidirectional connectivity
-- confirmed across both previously
-- isolated routing domains

Key Takeaway

Each protocol imposes its own seed metric requirement on redistributed routes since a route's original metric (an EIGRP composite value or an OSPF cost) has no meaningful translation into the receiving protocol's metric system — OSPF requires only a single metric value plus the subnets keyword, while EIGRP demands all five composite metric components explicitly, and forgetting either requirement (subnets for OSPF, the full five-part metric for EIGRP) is one of the most common redistribution configuration mistakes.