Configure Redistribute Internal BGP Routes into IGP

Available Languages

Download Options

PDF (183.7 KB)
View with Adobe Reader on a variety of devices
ePub (178.5 KB)
View in various apps on iPhone, iPad, Android, Sony Reader, or Windows Phone
Mobi (Kindle) (151.0 KB)
View on Kindle device or Kindle app on multiple devices

Updated:October 24, 2016

Document ID:200782

Bias-Free Language

The documentation set for this product strives to use bias-free language. For the purposes of this documentation set, bias-free is defined as language that does not imply discrimination based on age, disability, gender, racial identity, ethnic identity, sexual orientation, socioeconomic status, and intersectionality. Exceptions may be present in the documentation due to language that is hardcoded in the user interfaces of the product software, language used based on RFP documentation, or language that is used by a referenced third-party product. Learn more about how Cisco is using Inclusive Language.

Introduction

This document describes how to redistribute internal Border Gateway Protocol (BGP) routes into Open Shortest Path First (OSPF) process.

Prerequisites

Requirements

Cisco recommends that you have knowledge of basic BGP configuration and understand routing protocols of:

BGP
OSPF
Enhanced Interior Gateway Routing Protocol (EIGRP)
Routing Information Protocol (RIP)

For more information, refer to BGP Case Studies and Configuring BGP.

Components Used

The information in this document is based on the Cisco IOS® Software Release 15.1(4)M5.

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, ensure that you understand the potential impact of any command.

Background Information

Like in other Interior Gateway Protocol (IGP) to IGP redistribution, the behavior is different when Internal BGP (IBGP) is redistributed into OSPF. IBGP learned routes are not forwarded to an IGP routing protocol through the redistribute command. Use command bgp redistribute-internal under the BGP process on the router that redistributes.

Configure

Network Diagram

Configure OSPF between R2 & R3

In the scenario depicted here, routers R1 and R2 run IBGP, and routers R2 or R3 run OSPF Area 0. R1 advertises two routes (1.1.1.1 /32 and 10.10.10.10/32) through network command.
R2 redistributes BGP into OSPF Area 0. It is required to redistribute selected internal routes (10.10.10.10/32).
The task is achieved with the use of prefix-list and route-map.

R1:

interface Loopback0
ip address 1.1.1.1 255.255.255.255
!
interface Loopback10
ip address 10.10.10.10 255.255.255.255
!
interface GigabitEthernet0/1
ip address 192.168.1.1 255.255.255.0
duplex auto
speed auto
!
router bgp 10
no synchronization
bgp router-id 1.1.1.1
bgp log-neighbor-changes
network 1.1.1.1 mask 255.255.255.255
network 10.10.10.10 mask 255.255.255.255
neighbor 192.168.1.2 remote-as 100
no auto-summary

R1#show ip bgp summary 
BGP router identifier 10.10.10.10, local AS number 10
BGP table version is 3, main routing table version 3
2 network entries using 296 bytes of memory
2 path entries using 128 bytes of memory
1/1 BGP path/bestpath attribute entries using 136 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 560 total bytes of memory
BGP activity 2/0 prefixes, 2/0 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
192.168.1.2 4 10 6 7 3 0 0 00:03:10 0

R2:

interface Loopback0
ip address 2.2.2.2 255.255.255.255
!
interface GigabitEthernet0/0
ip address 192.168.1.2 255.255.255.0
duplex auto
speed auto
!
interface GigabitEthernet0/1
ip address 10.1.1.1 255.255.255.0
duplex auto
speed auto
!

router ospf 1
router-id 2.2.2.2
log-adjacency-changes
redistribute bgp 100 metric 100 metric-type 1 subnets route-map BGP-To_OSPF
network 10.1.1.1.1 0.0.0.0 area 0

R2#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
3.3.3.3 1 FULL/BDR 00:00:38 10.1.1.2 GigabitEthernet0/1

router bgp 10
no synchronization
bgp router-id 2.2.2.2
bgp log-neighbor-changes
bgp redistribute-internal
neighbor 192.168.12.1 remote-as 10
no auto-summary
!
ip prefix-list BGP-to-ospf seq 5 permit 172.16.0.0/16
!
route-map BGP-To_OSPF permit 10
match ip address prefix-list BGP-to-ospf

R2#show ip bgp summary 
BGP router identifier 192.168.1.2, local AS number 10
BGP table version is 3, main routing table version 3
2 network entries using 272 bytes of memory
2 path entries using 112 bytes of memory
1/1 BGP path/bestpath attribute entries using 128 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 512 total bytes of memory
BGP activity 2/0 prefixes, 2/0 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
192.168.1.1 4 10 8 7 3 0 0 00:03:52 2
R2#show ip bgp 
BGP table version is 3, local router ID is 192.168.1.2
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, x best-external, f RT-Filter
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*>i1.1.1.1/32 192.168.1.1 0 100 0 i
*>i10.10.10.10/32 192.168.1.1 0 100 0 i

R2#show ip route 1.1.1.1
Routing entry for 1.1.1.1/32
Known via "bgp 10", distance 200, metric 0, type internal
Last update from 192.168.1.1 00:04:53 ago
Routing Descriptor Blocks:
* 192.168.1.1, from 192.168.1.1, 00:04:53 ago
Route metric is 0, traffic share count is 1
AS Hops 0
MPLS label: none

R2#show ip route 10.10.10.10
Routing entry for 10.10.10.10/32
Known via "bgp 10", distance 200, metric 0, type internal
Last update from 192.168.1.1 00:04:56 ago
Routing Descriptor Blocks:
* 192.168.1.1, from 192.168.1.1, 00:04:56 ago
Route metric is 0, traffic share count is 1
AS Hops 0
MPLS label: none

R3:

interface FastEthernet1/0
ip address 10.1.1.2 255.255.255.0
duplex auto
speed auto

router ospf 1
log-adjacency-changes
network 10.1.1.2 0.0.0.0 area 0

R3#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
192.168.1.2 1 FULL/DR 00:00:36 10.1.1.1 GigabitEthernet0/1

The routing table in R3 before BGP redistribute - internal is added on R2 under router BGP 10:

R3#show ip route
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area 
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
+ - replicated route, % - next hop override
Gateway of last resort is not set
3.0.0.0/32 is subnetted, 1 subnets
C 3.3.3.3 is directly connected, Loopback0
10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 10.1.1.0/24 is directly connected, GigabitEthernet0/1
L 10.1.1.2/32 is directly connected, GigabitEthernet0/1

R2:

router bgp 10
bgp redistribute-internal

Verify

R3:

The routing table for R3 after BGP redistribute - internal is added on R2 under router BGP 10:

R3#show ip route 
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area 
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
+ - replicated route, % - next hop override
Gateway of last resort is not set
3.0.0.0/32 is subnetted, 1 subnets
C 3.3.3.3 is directly connected, Loopback0
10.0.0.0/8 is variably subnetted, 3 subnets, 2 masks
C 10.1.1.0/24 is directly connected, GigabitEthernet0/1
L 10.1.1.2/32 is directly connected, GigabitEthernet0/1
O E1 10.10.10.10/32 [110/11] via 10.1.1.1, 00:00:06, GigabitEthernet0/1

Configure EIGRP between R2 & R3:

In the scenario depicted here, routers R1 and R2 run IBGP, and routers R2 or R3 run EIGRP Autonomous System (AS) 1. R1 advertises two routes (1.1.1.1 /32 and 10.10.10.10/32) through network command.
R2 redistributes BGP into EIGRP AS 1. It is required to redistribute selected internal routes (10.10.10.10/32).
The task is achieved with the use of prefix-list and route-map.

R2:

router eigrp 1
network 10.0.0.0
redistribute bgp 10 metric 1544 10 255 1 1500 route-map BGP_To_EIGRP
eigrp router-id 2.2.2.2

route-map BGP_To_EIGRP, permit, sequence 10
Match clauses:
ip address prefix-lists: BGP-to-eigrp 
Set clauses:
Policy routing matches: 0 packets, 0 bytes


 ip prefix-list BGP-to-eigrp: 1 entries
 seq 1 permit 10.10.10.10/32

R3:

router eigrp 1
network 10.0.0.0
eigrp router-id 3.3.3.3

The output of the show IP route on R3 before BGP redistribute - internal is added on R2 under router BGP 10:

R3#show ip route 
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area 
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
+ - replicated route, % - next hop override
Gateway of last resort is not set
3.0.0.0/32 is subnetted, 1 subnets
C 3.3.3.3 is directly connected, Loopback0
10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 10.1.1.0/24 is directly connected, GigabitEthernet0/1
L 10.1.1.2/32 is directly connected, GigabitEthernet0/1

R2:

router bgp 10
bgp redistribute-internal

Verify

The output of the show IP route on R3 after BGP redistribute-internal is added on R2 under router BGP 10:

R3#show ip route 
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area 
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
+ - replicated route, % - next hop override
Gateway of last resort is not set
3.0.0.0/32 is subnetted, 1 subnets
C 3.3.3.3 is directly connected, Loopback0
10.0.0.0/8 is variably subnetted, 3 subnets, 2 masks
C 10.1.1.0/24 is directly connected, GigabitEthernet0/1
L 10.1.1.2/32 is directly connected, GigabitEthernet0/1
D EX 10.10.10.10/32 
[170/1660672] via 10.1.1.1, 00:00:04, GigabitEthernet0/1

Configure RIP between R2 & R3:

In the scenario depicted here, routers R1 and R2 run IBGP, and routers R2 or R3 run RIPv2.

R1 advertises two routes (1.1.1.1 /32 and 10.10.10.10/32) through network command.
R2 redistributes BGP into RIPv2. It is required to redistribute selected internal routes (10.10.10.10/32).
The task is achieved with the use of prefix-list and route-map.

R2:

router rip
version 2
redistribute bgp 10 metric 1 route-map BGP_To_RIP
network 10.0.0.0
no auto-summary

route-map BGP_To_RIP, permit, sequence 10
Match clauses:
ip address prefix-lists: BGP-to-rip 
Set clauses:
Policy routing matches: 0 packets, 0 bytes

ip prefix-list BGP-to-rip: 1 entries
seq 1 permit 10.10.10.10/32

R3:

router rip
version 2
network 10.0.0.0
no auto-summary

Output on R3 before you enable BGP redistribute-internal on R2 under router BGP 10:

R3#show ip route 
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area 
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
+ - replicated route, % - next hop override
Gateway of last resort is not set
3.0.0.0/32 is subnetted, 1 subnets
C 3.3.3.3 is directly connected, Loopback0
10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 10.1.1.0/24 is directly connected, GigabitEthernet0/1
L 10.1.1.2/32 is directly connected, GigabitEthernet0/1

R2:

router bgp 10
bgp redistribute-internal

Verify

Output on R3 after you enable BGP redistribute - internal on R2 under router BGP 10:

R3#sh ip route 
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area 
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
+ - replicated route, % - next hop override
Gateway of last resort is not set
3.0.0.0/32 is subnetted, 1 subnets
C 3.3.3.3 is directly connected, Loopback0
10.0.0.0/8 is variably subnetted, 3 subnets, 2 masks
C 10.1.1.0/24 is directly connected, GigabitEthernet0/1
L 10.1.1.2/32 is directly connected, GigabitEthernet0/1
R 10.10.10.10/32 [120/1] via 10.1.1.1, 00:00:09, GigabitEthernet0/1

Troubleshoot

There is currently no specific troubleshoot information available for this configuration.

Revision History

Revision	Publish Date	Comments
1.0	25-Oct-2016	Initial Release

Contributed by Cisco Engineers

Gaurav Mahajan
Cisco TAC Engineer

Was this Document Helpful?

Feedback

Contact Cisco

Open a Support Case
(Requires a Cisco Service Contract)

This Document Applies to These Products

IP Routing

Configure Redistribute Internal BGP Routes into IGP

Available Languages

Download Options

Bias-Free Language

Contents

Introduction

Prerequisites

Requirements

Components Used

Background Information

Configure

Network Diagram

Configure OSPF between R2 & R3

Verify

Configure EIGRP between R2 & R3:

Verify

Configure RIP between R2 & R3:

Verify

Troubleshoot

Revision History

Contributed by Cisco Engineers

Was this Document Helpful?

Contact Cisco

This Document Applies to These Products