bgp inject-map

[Balajee Muggalla]

Hi,

    I am trying to test bgp inject-map using gns3 and am facing some problem. I am using the following topology.

|R7 AS 1000|-----|R3 AS 1200|-----|R4 AS 1000|

R7 is sending some aggregate 172.16.0.0/16 to R3. I want to generate 172.16.9.0/24 along with aggregate and send to R4.

R3:

==

router bgp 1200

no synchronization

bgp log-neighbor-changes

bgp inject-map advert exist-map check

neighbor 10.1.2.4 remote-as 1300

neighbor 10.1.2.4 ebgp-multihop 2

neighbor 10.1.2.4 update-source Loopback0

neighbor 10.1.2.4 next-hop-self

neighbor 10.1.2.4 send-community

neighbor 10.1.2.7 remote-as 1000

neighbor 10.1.2.7 ebgp-multihop 2

neighbor 10.1.2.7 update-source Loopback0

no auto-summary

R3#show route-map advert

route-map advert, permit, sequence 10

  Match clauses:

  Set clauses:

    ip address (prefix-list) adver

    community no-export

  Policy routing matches: 0 packets, 0 bytes

R3#show ip prefix-list adver

ip prefix-list adver: 1 entries

   seq 10 permit 172.16.7.0/24

R3#

R3#

R3#show route-map check

route-map check, permit, sequence 10

  Match clauses:

    ip address prefix-lists: leanred

    ip route-source prefix-lists: source

  Set clauses:

  Policy routing matches: 0 packets, 0 bytes

R3#

R3#show ip prefix-list learned

ip prefix-list learned: 1 entries

   seq 10 permit 172.16.0.0/16

R3#show ip prefix-list source

ip prefix-list source: 1 entries

   seq 10 permit 10.1.2.7/32

R3#

R3#

R3#show ip bgp

BGP table version is 2, local router ID is 30.1.2.1

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

*> 172.16.0.0       10.1.2.7                 0             0 1000 i

R3#

R4:

==

R4#show ip bgp

BGP table version is 6, local router ID is 40.1.2.1

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

*> 172.16.0.0       10.1.2.3                               0 1200 1000 i

R4#

As shown above, I am seeing only aggregate on R4, not specific. What could be wrong with my config? Your help is appreciated.

Thanks,

Balajee

[paul driver]

Hello Balajee,

Not tested this but can you try perfoming the inject-map on R4 instead?

something like this:

R4

ip prefix-list NETWORK permit 172.16.7.0/24

ip prefix-list AGGREGATE permit 172.16.0.0/16

ip prefix-list R3 permit 10.1.2.3/24 ( i am asuming this is a 24 bit towards R3 from R4)

route-map EXIST permit 10

match ip address prefix-list AGGREGATE

match ip address prefix-list R3

route-map INJECT permit 10

match ip address prefix-list NETWORK

router bgp 1000

bgp inject-map INJECT exist-map EXIST

so if i am correct - this is telling the router to check if the 172.16.0.0/16 exists and  R3 is up then call the inject map and inject the 172.16.7.0/24

res

Paul

[milan.kulik]

Hi,

according to http://www.cisco.com/en/US/customer/docs/ios/12_2t/12_2t4/feature/guide/ftbgpri.html

your config looks correct.

I suppose sh ip bgp injected-paths does not show the  172.16.7.0/24 prefix withion the R3 BGP table?

I guess there might be some bug in your IOS?

Possibly bringing a trouble with this feature while using eBGP multihop?

What about trying to use a simple peering using interface IP addresses?

Or removing the  set community no-export command from your route-map?

BR,

Milan

[Jose Jara]

Hi Balajee,

I see two things in your config:

1.

R3#show route-map check

route-map check, permit, sequence 10

  Match clauses:

    ip address prefix-lists: leanred --------------- it should be learned, the name of your prefix-list created

    ip route-source prefix-lists: source

2.

R3#show route-map advert

route-map advert, permit, sequence 10

  Match clauses:

  Set clauses:

    ip address (prefix-list) adver

    community no-export ---------------------------- it should be removed here, if you want to apply the no-export community to apply it for the eBGP neighbor, put a route-map in the outbound direction.

For verification you can use: show ip bgp injected-paths

Hope this telps,

Jose.

[Balajee Muggalla]

Ohhhhhh.....great catch. Stupid mistake from me. Thanks a lot and appreciate your help.

Thanks,

Balajee

[Balajee Muggalla]

Forgot to add....after making the changes suggested by you, it worked.