Scalable EIGRP-to-BGP Route Redistribution in Enterprise Edge Designs

January 2010    |   Reading time: 10 min

Enterprises in 2010 are increasingly running dual protocols — EIGRP internally and BGP externally — at the network edge. Route redistribution between the two requires careful planning to avoid loops, instability, and unnecessary route injection.

Scenario Overview

Consider an enterprise network using EIGRP as its internal routing protocol. At the edge, the company connects to multiple ISPs running eBGP. The design goal is to redistribute internal routes to BGP selectively, while also injecting BGP-learned prefixes into EIGRP only where necessary.

Configuration Walkthrough

router eigrp 100
 redistribute bgp 65001 route-map BGP_TO_EIGRP
!
router bgp 65001
 redistribute eigrp 100 route-map EIGRP_TO_BGP
!
route-map EIGRP_TO_BGP permit 10
 match ip address prefix-list INTERNAL_ROUTES
 set local-preference 200
!
ip prefix-list INTERNAL_ROUTES seq 5 permit 10.10.0.0/16 le 24
  

Explanation and Rationale

The configuration uses route-maps to control redistribution. Only prefixes permitted by the prefix-list INTERNAL_ROUTES are redistributed from EIGRP into BGP, preventing accidental advertisement of internal-only routes. Local preference is set to influence outbound traffic policies.

Verification and Testing

show ip bgp
show ip route
show ip eigrp topology
  

These commands verify that only intended routes are present. The BGP table should show selected internal routes, and the EIGRP topology should only contain BGP-learned routes allowed by the redistribution policy.

Conclusion

Redistribution between EIGRP and BGP remains a core design challenge in enterprise edge networks. By using route-maps, prefix-lists, and policy-based control, administrators can scale networks securely while maintaining deterministic routing behavior.

Eduardo Wnorowski is a network infrastructure consultant and technologist.
With over 15 years of experience in IT and consulting, he brings deep expertise in networking, security, infrastructure, and transformation.
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