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route-map with BGP

lazhar.ch
Level 1
Level 1

Hello all,

i have a problem with route-map under bgp process.

i have two routers R1 (AS80) and R2(AS100) connected via serial 0/0 192.168.100.1/30

i configured an ebgp peering between the two routers

when i try to advertise some networks from R1 to R2 with route-map to test some BGP features, i have o match in route-map and no effect in the network received by R2

the configuration of  R1:

version 12.3

service timestamps debug datetime msec

service timestamps log datetime msec

no service password-encryption

!

hostname R1

!

boot-start-marker

boot-end-marker

no aaa new-model

ip subnet-zero

no ip domain lookup

ip ssh break-string

ip audit notify log

ip audit po max-events 100

no ftp-server write-enable

!

interface Loopback0

ip address 172.17.0.1 255.255.255.255

!

interface Loopback1

ip address 10.10.10.1 255.255.255.0

!

interface Loopback2

ip address 10.10.11.1 255.255.255.0

!

interface Loopback3

ip address 10.10.20.1 255.255.255.0

!

interface FastEthernet0/0

no ip address

shutdown

duplex auto

speed auto

!

interface Serial0/0

ip address 192.168.100.1 255.255.255.252

clockrate 2000000

!

interface FastEthernet0/1

no ip address

shutdown

duplex auto

speed auto

!

interface Serial0/1

no ip address

shutdown

clockrate 2000000

!

router bgp 80

no synchronization

bgp router-id 172.17.0.1

bgp log-neighbor-changes

network 10.10.10.0 mask 255.255.255.0 route-map R2-OUT

network 10.10.11.0 mask 255.255.255.0

network 10.10.20.0 mask 255.255.255.0 route-map R2-OUT

neighbor 192.168.100.2 remote-as 100

no auto-summary

!

ip classless

!

ip bgp-community new-format

ip http server

no ip http secure-server

!

!

!

ip prefix-list PL-R2-OUT1 seq 10 permit 10.10.10.0/24

!

ip prefix-list PL-R2-OUT2 seq 10 permit 10.10.20.0/24

!

route-map R2-OUT permit 10

match ip address prefix-list  PL-R2-OUT1

set as-path prepend 1000 2000 3000

!

route-map R2-OUT permit 20

match ip address prefix-list PL-R2-OUT2

set as-path prepend 777 888 999

!

route-map R2-OUT permit 1000

!

control-plane

line con 0

exec-timeout 0 0

logging synchronous

line aux 0

line vty 0 4

login

R1#sh route-map

route-map R2-OUT, permit, sequence 10

  Match clauses:

    ip address (access-lists): 10

  Set clauses:

    as-path prepend 1000 2000 3000

  Policy routing matches: 0 packets, 0 bytes

route-map R2-OUT, permit, sequence 20

  Match clauses:

    ip address prefix-lists: PL-R2-OUT2

  Set clauses:

    as-path prepend 777 888 999

  Policy routing matches: 0 packets, 0 bytes

route-map R2-OUT, permit, sequence 30

  Match clauses:

    ip address prefix-lists: PL-R2-OUT3

  Set clauses:

    community 80:300 80:400 additive

  Policy routing matches: 0 packets, 0 bytes

route-map R2-OUT, permit, sequence 1000

  Match clauses:

  Set clauses:

  Policy routing matches: 0 packets, 0 bytes

R2#sh ip bgp

BGP table version is 14, local router ID is 172.17.0.2

Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,

              r RIB-failure, S Stale

Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path

*> 10.10.10.0/24    192.168.100.1            0             0 80 i

*> 10.10.11.0/24    192.168.100.1            0             0 80 i

*> 10.10.20.0/24    192.168.100.1            0             0 80 i

it's clear that the route-map doesn't have any effect in the advertisement.

why i have 0 matching in the route-map? is there any issue in the configuration?

2 Accepted Solutions

Accepted Solutions

Edison Ortiz
Hall of Fame
Hall of Fame

The route-map must be applied at the neighbor level as the BGP prefix will have its BGP attribute modified as it leaves the router, not during a network advertisement.

Your config should look like:

router bgp 80

no synchronization

bgp router-id 172.17.0.1

bgp log-neighbor-changes

network 10.10.10.0 mask 255.255.255.0

network 10.10.11.0 mask 255.255.255.0

network 10.10.20.0 mask 255.255.255.0

neighbor 192.168.100.2 remote-as 100

neighbor 192.168.100.2 route-map R2-OUT out

no auto-summary

View solution in original post

A route-map at the network level can be used for anything other than to apply BGP attributes.

For instance, applying a tag to a subnet can be done with a network level route-map.

I rarely use network level route-map because of its limited functionality.

The route-map to use when modifying BGP attributes must be the one at the neighbor level as BGP attributes get modified when entering or exiting the router, not on the router itself.

Regards

Edison.

Please remember to rate helpful posts !

View solution in original post

4 Replies 4

Edison Ortiz
Hall of Fame
Hall of Fame

The route-map must be applied at the neighbor level as the BGP prefix will have its BGP attribute modified as it leaves the router, not during a network advertisement.

Your config should look like:

router bgp 80

no synchronization

bgp router-id 172.17.0.1

bgp log-neighbor-changes

network 10.10.10.0 mask 255.255.255.0

network 10.10.11.0 mask 255.255.255.0

network 10.10.20.0 mask 255.255.255.0

neighbor 192.168.100.2 remote-as 100

neighbor 192.168.100.2 route-map R2-OUT out

no auto-summary

thanks Edison it works

but i would like to know the difference between using route-map at the neighbor level and at the network level and when we use each one?

A route-map at the network level can be used for anything other than to apply BGP attributes.

For instance, applying a tag to a subnet can be done with a network level route-map.

I rarely use network level route-map because of its limited functionality.

The route-map to use when modifying BGP attributes must be the one at the neighbor level as BGP attributes get modified when entering or exiting the router, not on the router itself.

Regards

Edison.

Please remember to rate helpful posts !

Thanks Edison for the helpful reponse

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