Problem With Redistribute Ospf into BGP with as-path prepend

[Erico Verissimo]

Hello all,

I have prefixes received by ospf and i wanna to redistribute into BGP, however, i need to get worse 50% of those prefixes using as-path prepend.

CISCO3945-CHASSIS

RT01_MPLS_OI_TRK(config-router-af)#redistribute static route-map redes_jbq_prepend
% "redes_jbq_prepend" used as redistribute static into bgp route-map, set as-path prepend not supported.

I have got the message above and i would know if there is an other way to get worse the prefixes.

Thanks for any support or suggestion.

[Georg Pauwen]

Hello,

what are you trying to redistribute ? Static routes ? Post the config of what you have configured...

[Erico Verissimo]

Hello,

Following the config:

router ospf 100
router-id 10.206.4.13
log-adjacency-changes
auto-cost reference-bandwidth 100000
passive-interface GigabitEthernet0/2
network 10.206.4.0 0.0.0.255 area 0
network 192.168.151.76 0.0.0.3 area 0
network 192.168.151.112 0.0.0.3 area 0
!
router bgp 65115
bgp router-id 10.206.4.13
bgp log-neighbor-changes
neighbor 100.127.105.205 remote-as 7738
!
address-family ipv4
no synchronization
redistribute static
redistribute ospf 100 route-map OSPF_para_BGP
neighbor 100.127.105.205 activate
neighbor 100.127.105.205 soft-reconfiguration inbound
neighbor 100.127.105.205 filter-list 1 in
default-information originate
no auto-summary
exit-address-family

ip prefix-list anunciar_ao_BGP_JBQ seq 3 permit 0.0.0.0/0
ip prefix-list anunciar_ao_BGP_JBQ seq 4 permit 10.98.98.0/23
ip prefix-list anunciar_ao_BGP_JBQ seq 5 permit 10.98.0.0/28
ip prefix-list anunciar_ao_BGP_JBQ seq 7 permit 14.14.14.14/32
ip prefix-list anunciar_ao_BGP_JBQ seq 10 permit 10.99.5.224/27
ip prefix-list anunciar_ao_BGP_JBQ seq 11 permit 192.168.128.0/22
ip prefix-list anunciar_ao_BGP_JBQ seq 12 permit 192.168.134.0/28
ip prefix-list anunciar_ao_BGP_JBQ seq 15 permit 10.100.0.0/16
ip prefix-list anunciar_ao_BGP_JBQ seq 17 permit 10.123.0.0/24
ip prefix-list anunciar_ao_BGP_JBQ seq 20 permit 10.127.1.0/28
ip prefix-list anunciar_ao_BGP_JBQ seq 21 permit 10.127.4.0/23
ip prefix-list anunciar_ao_BGP_JBQ seq 26 permit 10.127.2.0/26
ip prefix-list anunciar_ao_BGP_JBQ seq 45 permit 10.254.0.0/24 le 27
ip prefix-list anunciar_ao_BGP_JBQ seq 55 permit 158.98.177.119/32
ip prefix-list anunciar_ao_BGP_JBQ seq 60 permit 158.98.183.171/32
ip prefix-list anunciar_ao_BGP_JBQ seq 65 permit 158.98.183.172/32
ip prefix-list anunciar_ao_BGP_JBQ seq 80 permit 192.168.200.0/24
!
ip prefix-list anunciar_ao_BGP_TRK seq 3 permit 0.0.0.0/0
ip prefix-list anunciar_ao_BGP_TRK seq 22 permit 10.127.6.0/23
ip prefix-list anunciar_ao_BGP_TRK seq 25 permit 10.127.1.16/28
ip prefix-list anunciar_ao_BGP_TRK seq 27 permit 10.129.25.0/24
ip prefix-list anunciar_ao_BGP_TRK seq 30 permit 10.206.0.0/16 le 24
ip prefix-list anunciar_ao_BGP_TRK seq 31 permit 10.206.2.0/27
ip prefix-list anunciar_ao_BGP_TRK seq 35 permit 10.208.0.0/16 le 24
ip prefix-list anunciar_ao_BGP_TRK seq 42 permit 172.16.85.0/24
ip prefix-list anunciar_ao_BGP_TRK seq 43 permit 172.16.88.0/24
ip prefix-list anunciar_ao_BGP_TRK seq 50 permit 129.73.116.88/29
ip prefix-list anunciar_ao_BGP_TRK seq 51 permit 172.16.37.0/24
ip prefix-list anunciar_ao_BGP_TRK seq 70 permit 192.68.48.0/22
ip prefix-list anunciar_ao_BGP_TRK seq 75 permit 194.138.39.16/29
ip prefix-list anunciar_ao_BGP_TRK seq 85 permit 150.2.0.0/16
ip prefix-list anunciar_ao_BGP_TRK seq 86 permit 10.128.101.0/24

route-map OSPF_para_BGP permit 10
match ip address prefix-list anunciar_ao_BGP_TRK
!
route-map OSPF_para_BGP permit 20
match ip address prefix-list anunciar_ao_BGP_JBQ
set as-path prepend 65115 65115 65115

On the other site i see, for example, the net 10.100.0.0 as below:

fm-rt01-samaritano_core#sh ip bgp 10.100.0.0
BGP routing table entry for 10.100.0.0/16, version 27206
Paths: (2 available, best #2, table default)
Not advertised to any peer
10429 65000
187.50.82.53 from 187.50.82.53 (186.200.157.65)
Origin incomplete, localpref 100, valid, external
Extended Community: RT:10429:4811
7738 65115
100.126.101.125 from 100.126.101.125 (200.195.97.10)
Origin incomplete, localpref 150, valid, external, best

[Julio E. Moisa]

Hi

AS Path prepend is used under route-maps for BGP purposes only for example to advertise a desirable path or not or for symmetric traffic to a BGP peer, for example you could use

ip prefix-list anunciar_ao_BGP_JBQ seq 3 permit 0.0.0.0/0
ip prefix-list anunciar_ao_BGP_JBQ seq 4 permit 10.98.98.0/23
ip prefix-list anunciar_ao_BGP_JBQ seq 5 permit 10.98.0.0/28
ip prefix-list anunciar_ao_BGP_JBQ seq 7 permit 14.14.14.14/32
ip prefix-list anunciar_ao_BGP_JBQ seq 10 permit 10.99.5.224/27
ip prefix-list anunciar_ao_BGP_JBQ seq 11 permit 192.168.128.0/22
ip prefix-list anunciar_ao_BGP_JBQ seq 12 permit 192.168.134.0/28
ip prefix-list anunciar_ao_BGP_JBQ seq 15 permit 10.100.0.0/16
ip prefix-list anunciar_ao_BGP_JBQ seq 17 permit 10.123.0.0/24
ip prefix-list anunciar_ao_BGP_JBQ seq 20 permit 10.127.1.0/28
ip prefix-list anunciar_ao_BGP_JBQ seq 21 permit 10.127.4.0/23
ip prefix-list anunciar_ao_BGP_JBQ seq 26 permit 10.127.2.0/26
ip prefix-list anunciar_ao_BGP_JBQ seq 45 permit 10.254.0.0/24 le 27
ip prefix-list anunciar_ao_BGP_JBQ seq 55 permit 158.98.177.119/32
ip prefix-list anunciar_ao_BGP_JBQ seq 60 permit 158.98.183.171/32
ip prefix-list anunciar_ao_BGP_JBQ seq 65 permit 158.98.183.172/32
ip prefix-list anunciar_ao_BGP_JBQ seq 80 permit 192.168.200.0/24
!
ip prefix-list anunciar_ao_BGP_TRK seq 3 permit 0.0.0.0/0
ip prefix-list anunciar_ao_BGP_TRK seq 22 permit 10.127.6.0/23
ip prefix-list anunciar_ao_BGP_TRK seq 25 permit 10.127.1.16/28
ip prefix-list anunciar_ao_BGP_TRK seq 27 permit 10.129.25.0/24
ip prefix-list anunciar_ao_BGP_TRK seq 30 permit 10.206.0.0/16 le 24
ip prefix-list anunciar_ao_BGP_TRK seq 31 permit 10.206.2.0/27
ip prefix-list anunciar_ao_BGP_TRK seq 35 permit 10.208.0.0/16 le 24
ip prefix-list anunciar_ao_BGP_TRK seq 42 permit 172.16.85.0/24
ip prefix-list anunciar_ao_BGP_TRK seq 43 permit 172.16.88.0/24
ip prefix-list anunciar_ao_BGP_TRK seq 50 permit 129.73.116.88/29
ip prefix-list anunciar_ao_BGP_TRK seq 51 permit 172.16.37.0/24
ip prefix-list anunciar_ao_BGP_TRK seq 70 permit 192.68.48.0/22
ip prefix-list anunciar_ao_BGP_TRK seq 75 permit 194.138.39.16/29
ip prefix-list anunciar_ao_BGP_TRK seq 85 permit 150.2.0.0/16
ip prefix-list anunciar_ao_BGP_TRK seq 86 permit 10.128.101.0/24

route-map FILTERING-OUT permit 10
match ip address prefix-list anunciar_ao_BGP_TRK
!
route-map FILTERING-OUT permit 20
match ip address prefix-list anunciar_ao_BGP_JBQ
set as-path prepend 65115 65115 65115

Router  BGP 65114

address-family ipv4 

no redistribute ospf 100 route-map OSPF_para_BGP

network 10.100.0.0 mask 255.255.0.0

neighbor 100.127.105.205 route-map FILTERING-OUT out

[Erico Verissimo]

Georg...thank you for your attention ..

The problem was resolved.

[Julio E. Moisa · Accepted solution]

Hi

Have you consider advertise the routes via BGP (using network command)  as they are already included into the routing table and matching and setting attributes using ip prefix-list and route-maps?

[Erico Verissimo]

Thank you Julio for the informations... 

I think the problem it was resolved..

I kept the config:

 redistribute ospf 100 route-map OSPF_para_BGP

Add the line:

neighbor 100.127.105.205 route-map redes_jbq_prepend out

//this line is linked to: 

route-map redes_jbq_prepend permit 10
match ip address prefix-list anunciar_ao_BGP_JBQ
set as-path prepend 65115 65115 65115
!
route-map redes_jbq_prepend permit 20

//

The last line (route-map redes_jbq_prepend permit 20) was able the rest of prefixes advertised by BGP with as-path prepend.

The result in other site was as below:

BGP routing table entry for 14.14.14.14/32, version 2959
Paths: (1 available, best #1, table default)
Not advertised to any peer
7738 65115 65115 65115 65115
100.127.83.253 from 100.127.83.253 (200.195.97.10)

Thanks..
Origin incomplete, localpref 100, valid, external, best