Complete Guide to EIGRP and RIP Redistribution

Introduction to Route Redistribution

Redistribution is the process of importing routes learned by one routing protocol into another protocol. Different protocols like RIP and EIGRP don't communicate by default because they use different metrics for path selection.

Why Redistribution Matters

RIP uses hop-count for path selection
EIGRP uses bandwidth and delay for path selection
Without proper metric conversion, routes won't be shared between protocols

Network Topology

Network topology showing EIGRP and RIP redistribution

Network Details:

PC's

PC1: 192.168.10.1/24
PC2: 192.168.20.1/24
PC3: 192.168.30.1/24

R1 (EIGRP Only)

Fa0/0: 192.168.10.1/24
S5/0: 200.1.12.1/30
EIGRP AS 10

R2 (ASBR - EIGRP & RIP)

Fa0/0: 192.168.20.1/24
S5/0: 200.1.12.2/30
S5/1: 14.1.1.2/8
EIGRP AS 10 & RIP

R3 (RIP Only)

Fa0/0: 192.168.30.1/24
S5/1: 14.1.1.1/8
RIP

PC Configurations:

IP Configuration

PC1> ip 192.168.10.5 255.255.255.0 192.168.10.1
PC2> ip 192.168.20.5 255.255.255.0 192.168.20.1
PC3> ip 192.168.30.5 255.255.255.0 192.168.30.1

Router Configurations

R1 Configuration (EIGRP):

Configuration

R1(config)# int f0/0
R1(config-if)# ip address 192.168.10.1 255.255.255.0
R1(config-if)# no shut
R1(config-if)# exit

R1(config)# int s5/0
R1(config-if)# ip address 200.1.12.1 255.255.255.252
R1(config-if)# no shut
R1(config-if)# exit

R1(config)# router eigrp 10
R1(config-router)# network 192.168.10.0
R1(config-router)# network 200.1.12.0 0.0.0.3
R1(config-router)# exit

R2 Configuration (ASBR):

Configuration

R2(config)# int f0/0
R2(config-if)# ip address 192.168.20.1 255.255.255.0
R2(config-if)# no shut
R2(config-if)# exit

R2(config)# int s5/0
R2(config-if)# ip address 200.1.12.2 255.255.255.252
R2(config-if)# no shut
R2(config-if)# exit

R2(config)# int s5/1
R2(config-if)# ip address 14.1.1.2 255.0.0.0
R2(config-if)# no shut
R2(config-if)# exit

R2(config)# router eigrp 10
R2(config-router)# network 192.168.20.0
R2(config-router)# network 200.1.12.0 0.0.0.3
R2(config-router)# exit

R2(config)# router rip
R2(config-router)# network 14.0.0.0
R2(config-router)# exit

R3 Configuration (RIP):

Configuration

R3(config)# int f0/0
R3(config-if)# ip address 192.168.30.1 255.255.255.0
R3(config-if)# no shut
R3(config-if)# exit

R3(config)# int s5/1
R3(config-if)# ip address 14.1.1.1 255.0.0.0
R3(config-if)# no shut
R3(config-if)# exit

R3(config)# router rip
R3(config-router)# network 192.168.30.0
R3(config-router)# network 14.0.0.0
R3(config-router)# exit

Configuring Redistribution

Redistribution is always configured on the ASBR (R2 in our topology) where both protocols meet.

EIGRP into RIP Redistribution:

Configuration

R2(config)# router rip
R2(config-router)# redistribute eigrp 10 metric 5
R2(config-router)# exit

Metric 5: RIP only understands hop-count, so we assign an arbitrary hop count of 5 to redistributed EIGRP routes.

RIP into EIGRP Redistribution:

Configuration

R2(config)# router eigrp 10
R2(config-router)# redistribute rip metric 1000 500 255 100 10
R2(config-router)# exit

Metric Components:
Bandwidth=1000, Delay=500, Reliability=255, Load=100, MTU=10

Verifying Redistribution

Routing Tables:

R1 Routing Table (EIGRP)

D EX 14.0.0.0/8 [150/3200000] via 200.1.12.2
D EX 192.168.30.0/24 [150/3200000] via 200.1.12.2
D 192.168.20.0/24 [100/2172416] via 200.1.12.2

D EX: External EIGRP route (redistributed from RIP)

R3 Routing Table (RIP)

R 192.168.10.0/24 [120/10] via 14.1.1.2
R 192.168.20.0/24 [120/10] via 14.1.1.2
R 200.1.12.0/24 [120/10] via 14.1.1.2

R: RIP route (redistributed from EIGRP)

Connectivity Tests:

PC3 → PC1 (RIP to EIGRP)

PC3> ping 192.168.10.5
84 bytes from 192.168.10.5 icmp_seq=1 ttl=61 time=93.779 ms

PC2 → PC3 (EIGRP to RIP)

PC2> ping 192.168.30.5
84 bytes from 192.168.30.5 icmp_seq=1 ttl=62 time=62.338 ms

EIGRP Metric Calculation

EIGRP uses a composite metric based on K values (weights) to calculate the best path:

Metric = 256 * [K1*B.W + K2*B.W + K3*delay] * [K5/(reliability+K4)]

Default K Values:

Default Values

K1 = 1 (Bandwidth)
K2 = 0 (Load)
K3 = 1 (Delay)
K4 = 0 (Reliability)
K5 = 0 (MTU)

This simplifies to: 256 * (Bandwidth + Delay)

Changing K Values:

Configuration

router eigrp [AS]
 metric weights [TOS] [K1] [K2] [K3] [K4] [K5]
 exit

Example:
router eigrp 10
 metric weights 0 1 0 1 1 0
 exit

Important Note

All routers in the same EIGRP AS must have identical K values
Mismatched K values will prevent neighbor relationships from forming

K Values Verification

All EIGRP routers must have matching K values for neighbor relationships to form.

Checking K Values:

Command

show ip protocols

R1 K Values

R2 K Values

Key Points About K Values:

K1 and K3 are set to 1 by default (Bandwidth and Delay)
K2, K4, and K5 are set to 0 by default
All routers in the same EIGRP AS must have identical K values
Mismatched K values will prevent neighbor relationships

Adjusting Administrative Distance

EIGRP allows changing AD values for both internal and external routes:

Configuration

router eigrp [AS]
 distance eigrp [internal-AD] [external-AD]
 exit

Example:
router eigrp 10
 distance eigrp 100 150
 exit

AD Values in Routing Table:

Internal routes: AD 100 (default is 90)
External routes: AD 150 (default is 170)

Conclusion

Redistribution between EIGRP and RIP requires careful attention to metric conversion and K value matching. By following these steps, you can successfully share routes between these protocols:

1

Configure basic EIGRP and RIP on respective routers
2

Set up redistribution on the ASBR with proper metrics
3

Verify matching K values on all EIGRP routers
4

Test connectivity and verify routing tables

Remember that redistribution is always configured on the ASBR where both protocols meet.

What's Next?

EIGRP: Configuration, Metrics, and Path Selection

RIP's basics, how to configure it, and tips to avoid common pitfalls.

Default Routing and Default Floating Routes

Learn the differences and when to use each approach

Routing Information Protocol (RIP)

RIP's basics, how to configure it, and tips to avoid common pitfalls.