Monday, May 11, 2026

Complete Cisco Nexus EIGRP Redistribution Lab Configuration Guide with Multi-AS Routing

Cisco Nexus EIGRP Configuration Lab Guide | Redistribution, Multi-AS EIGRP & End-to-End Routing

Complete Cisco Nexus EIGRP Redistribution & Multi-AS Routing Lab

This advanced Cisco networking tutorial explains how to configure EIGRP across Cisco routers and Cisco Nexus switches using multiple autonomous systems, redistribution, route-maps, and end-to-end routing verification. The guide also explains EIGRP metrics, DUAL algorithm concepts, route selection, administrative distance, feasible successors, and redistribution mathematics.

Key Learning Goal: This lab teaches how enterprise networks exchange routing information between multiple EIGRP autonomous systems using redistribution.

Table of Contents

1. EIGRP Lab Overview

Enhanced Interior Gateway Routing Protocol (EIGRP) is an advanced distance-vector routing protocol developed by Cisco. It combines the advantages of both distance-vector and link-state routing protocols.

This lab demonstrates:

  • Multi-AS EIGRP deployment
  • EIGRP neighbor formation
  • Loopback advertisement
  • EIGRP redistribution
  • Route-map usage
  • End-to-end dynamic routing
  • Route verification

EIGRP Administrative Distance

Internal EIGRP routes:

\[ AD = 90 \]

External EIGRP routes:

\[ AD = 170 \]

Lower administrative distance means higher trust.

2. Understanding EIGRP Fundamentals

EIGRP uses the DUAL (Diffusing Update Algorithm) algorithm to calculate loop-free paths. It supports fast convergence and unequal-cost load balancing.

Core Concept: EIGRP routers form neighbor relationships before exchanging routing information.

Main EIGRP Components

  • Neighbor Table
  • Topology Table
  • Routing Table
  • DUAL Algorithm
  • Feasible Successors
  • Reliable Updates

EIGRP Composite Metric Formula

Classic EIGRP metric:

\[ 256 \times \left( \frac{10^7}{\text{minimum bandwidth}} + \text{delay} \right) \]

Where:

  • Bandwidth is measured in Kbps
  • Delay is measured in tens of microseconds

3. Task 0 - Remove Static Routes

Before enabling EIGRP, all static routes from the previous lab must be removed. This prevents routing conflicts and ensures EIGRP dynamically learns routes.

Important: Static routes can override dynamically learned EIGRP routes due to lower administrative distance.

Example Static Route Removal

no ip route 10.1.1.23/32 192.1.30.23
no ip route 100.1.23.0/24 192.1.30.23

4. Task 1 - Configure EIGRP AS 12

R1 and R2 will form an EIGRP neighbor relationship inside Autonomous System 12.

Key Concept: EIGRP neighbors must belong to the same autonomous system number.

R1 EIGRP Configuration

router eigrp NX-12
 address-family ipv4 unicast autonomous-system 12
 eigrp router-id 10.1.1.1
 network 192.1.12.0

R2 EIGRP Configuration

router eigrp NX-12
 address-family ipv4 unicast autonomous-system 12
 eigrp router-id 10.1.1.2
 network 192.1.12.0
 network 2.0.0.0
 network 10.1.1.2 0.0.0.0
 network 100.1.2.0 0.0.0.255
Neighbor Verification 
R1# show ip eigrp neighbors

EIGRP-IPv4 Neighbors for AS(12)

H   Address         Interface     Hold Uptime
0   192.1.12.2      Et0/0         12   00:10:32

5. Task 2 - Configure EIGRP AS 100

R1, NX-01, and NX-02 participate in EIGRP Autonomous System 100.

R1 Configuration

router eigrp NEXUS
 address-family ipv4 unicast autonomous-system 100
 eigrp router-id 10.1.1.1
 network 192.1.10.0
 network 192.1.20.0
 network 1.0.0.0
 network 10.1.1.1 0.0.0.0
 network 100.1.1.0 0.0.0.255

NX-01 Configuration

feature eigrp

router eigrp NEXUS
 address-family ipv4 unicast
 autonomous-system 100
 router-id 10.1.1.21

interface loopback0
 ip router eigrp NEXUS

interface loopback1
 ip router eigrp NEXUS

interface loopback10
 ip router eigrp NEXUS

interface vlan10
 ip router eigrp NEXUS

NX-02 Configuration

feature eigrp

router eigrp NEXUS
 address-family ipv4 unicast
 autonomous-system 100
 router-id 10.1.1.22

interface loopback0
 ip router eigrp NEXUS

interface loopback1
 ip router eigrp NEXUS

interface loopback10
 ip router eigrp NEXUS

interface vlan20
 ip router eigrp NEXUS
Why NX-OS Uses Interface-Based EIGRP

NX-OS enables EIGRP directly on interfaces instead of relying entirely on network statements. This provides more granular control and improves scalability.

6. Task 3 - Configure EIGRP AS 13

NX-01 and NX-03 form EIGRP adjacency using Autonomous System 13.

NX-01 Configuration

router eigrp NX-13
 address-family ipv4 unicast
 autonomous-system 13
 router-id 10.1.1.21

interface vlan30
 ip router eigrp NX-13

NX-03 Configuration

feature eigrp

router eigrp NX-13
 address-family ipv4 unicast
 autonomous-system 13
 router-id 10.1.1.23

interface loopback0
 ip router eigrp NX-13

interface loopback1
 ip router eigrp NX-13

interface loopback10
 ip router eigrp NX-13

interface vlan30
 ip router eigrp NX-13

EIGRP Hello Timer Mathematics

Default Hello Timer:

\[ 5 \text{ seconds} \]

Default Hold Timer:

\[ 15 \text{ seconds} \]

Relationship:

\[ 15 = 3 \times 5 \]

7. Task 4 - Configure EIGRP AS 24

NX-02 and NX-04 form EIGRP adjacency using Autonomous System 24.

NX-02 Configuration

router eigrp NX-24
 address-family ipv4 unicast
 autonomous-system 24
 router-id 10.1.1.22

interface ethernet1/5
 ip router eigrp NX-24

NX-04 Configuration

feature eigrp

router eigrp NX-24
 address-family ipv4 unicast
 autonomous-system 24
 router-id 10.1.1.24

interface loopback0
 ip router eigrp NX-24

interface loopback1
 ip router eigrp NX-24

interface loopback10
 ip router eigrp NX-24

interface ethernet1/6
 ip router eigrp NX-24

8. Task 5 - Redistribution on R1

R1 redistributes routes between Autonomous System 12 and Autonomous System 100.

Redistribution Concept: Redistribution allows routes from one routing domain to be injected into another routing domain.

R1 Redistribution Configuration

router eigrp NEXUS
 address-family ipv4 unicast autonomous-system 100
 topology base
 redistribute eigrp 12

router eigrp NX-12
 address-family ipv4 unicast autonomous-system 12
 topology base
 redistribute eigrp 100

Route Redistribution Mathematics

If:

  • AS 12 contains 4 routes
  • AS 100 contains 8 routes

After redistribution:

\[ 4 + 8 = 12 \]

Both routing domains can learn all routes.

9. Task 6 - Redistribution on NX-01

NX-01 redistributes routes between EIGRP AS 100 and AS 13.

Access List and Route-Map Configuration

ip access-list ALL
 10 permit ip any any

route-map ALL-NETS
 match ip address ALL

Redistribution Configuration

router eigrp NX-13
 address-family ipv4 unicast
 redistribute eigrp NEXUS route-map ALL-NETS

router eigrp NEXUS
 address-family ipv4 unicast
 redistribute eigrp NX-13 route-map ALL-NETS
Why Use Route-Maps?

Route-maps provide filtering and policy control during redistribution. They determine which routes are allowed or denied.

10. Task 7 - Redistribution on NX-02

NX-02 redistributes routes between EIGRP AS 100 and AS 24.

NX-02 Configuration

ip access-list ALL
 10 permit ip any any

route-map ALL-NETS
 match ip address ALL

router eigrp NX-24
 address-family ipv4 unicast
 redistribute eigrp NEXUS route-map ALL-NETS

router eigrp NEXUS
 address-family ipv4 unicast
 redistribute eigrp NX-24 route-map ALL-NETS

EIGRP Feasible Distance Mathematics

If:

  • Successor metric = 1000
  • Backup route metric = 900

Then:

\[ 900 < 1000 \]

The backup route qualifies as a feasible successor.

11. Task 8 - Verify End-to-End Connectivity

After redistribution, all devices should learn all loopback networks dynamically.

Ping Verification

R1# ping 124.124.124.124

!!!!!
Success rate is 100 percent

NX-03# ping 2.2.2.2

64 bytes from 2.2.2.2
EIGRP Route Verification 
R1# show ip route eigrp

D EX 124.0.0.0/8
D    123.0.0.0/8
D    122.0.0.0/8

12. EIGRP Mathematics & Metric Calculations

Bandwidth Calculation

If minimum bandwidth:

\[ 100000 \text{ Kbps} \]

Then:

\[ \frac{10^7}{100000} = 100 \]

Delay Calculation

If total delay:

\[ 2000 \]

Metric:

\[ 256 \times (100 + 2000) \]

\[ 256 \times 2100 = 537600 \]

EIGRP Query Scope

If:

  • 10 neighbors receive queries
  • Each neighbor forwards to 5 additional routers

Potential query propagation:

\[ 10 \times 5 = 50 \]

13. Verification Commands

Command Purpose
show ip eigrp neighbors Displays EIGRP neighbors
show ip route eigrp Displays EIGRP routes
show ip eigrp topology Displays topology table
show running-config Displays active configuration
ping Tests connectivity
Sample Topology Table Output 
R1# show ip eigrp topology

P 123.0.0.0/8, 1 successors
 via 192.1.10.21

14. EIGRP Troubleshooting

Common EIGRP problems include:

  • AS number mismatch
  • K-value mismatch
  • Passive interface configuration
  • Missing network statements
  • Redistribution loops
  • Incorrect route-maps
Golden Rule: EIGRP neighbors must match AS number and K-values to form adjacency.

Troubleshooting Commands

show ip eigrp neighbors
show ip protocols
show ip route
show ip eigrp topology
debug eigrp packets

16. Conclusion

This Cisco Nexus EIGRP lab demonstrated:

  • EIGRP neighbor relationships
  • Multiple autonomous systems
  • Redistribution
  • Route-maps
  • Dynamic route exchange
  • Loopback advertisement
  • End-to-end routing verification

Understanding EIGRP redistribution is critical because enterprise networks often connect multiple routing domains together.

These skills directly apply to:

  • Enterprise campus networks
  • Data center fabrics
  • MPLS edge routing
  • Hybrid cloud deployments
  • Large-scale Cisco environments
Final Learning Point: EIGRP redistribution allows independent routing domains to exchange routes while maintaining scalability and routing control. Mastering redistribution is one of the most important advanced routing skills in enterprise networking.
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