BGP- Community -2

R6
route-map commun permit 10
 match ip address 1
 set community no-export
!
route-map commun permit 20
 match ip address 4
 set community no-advertise
!
route-map commun permit 30
 match ip address 5
 set community 200:100
!
route-map commun permit 59
 set community none
!
!
access-list 1 permit 69.1.0.0 0.0.255.255
access-list 4 permit 69.3.0.0 0.0.255.255
access-list 5 permit 69.2.0.0 0.0.255.255

----------------------------

router bgp 1.301
 bgp asnotation dot
 bgp log-neighbor-changes
 network 66.6.6.6 mask 255.255.255.255
 redistribute connected route-map permit
 neighbor 1.1.1.1 remote-as 101
 neighbor 1.1.1.1 ebgp-multihop 2
 neighbor 1.1.1.1 update-source Loopback0
 neighbor 1.1.1.1 send-community
 neighbor 1.1.1.1 route-map commun out

----------------------------------------
R1

'R1#sh ip bgp | in 69
 *>  69.1.0.0/16      6.6.6.6                  0             0 1.301 ?
 *>  69.2.0.0/16      6.6.6.6                  0             0 1.301 ?
 *>  69.3.0.0/16      6.6.6.6                  0             0 1.301 ?
 *>  69.4.0.0/16      6.6.6.6                  0             0 1.301 ?
R1#
R1(config)#ip bgp-community new-format



R1#sh ip bgp 69.1.1.1  |  in Community
      Community: no-export
R1#sh ip bgp 69.2.1.1  |  in Community
      Community: 200:100
R1#sh ip bgp 69.3.1.1  |  in Community
      Community: no-advertise
R1#sh ip bgp 69.4.1.1  |  in Community
R1#
----------------------------------------

router bgp 101
 neighbor 3.3.3.3 route-reflector-client
 neighbor 3.3.3.3 next-hop-self
 neighbor 3.3.3.3 send-community

R3
R3#sh ip bgp | in 69
 *>i 69.1.0.0/16      1.1.1.1                  0    100      0 1.301 ?
 *>i 69.2.0.0/16      1.1.1.1                  0    100      0 1.301 ?
 *>i 69.4.0.0/16      1.1.1.1                  0    100      0 1.301 ?
R3#
R3#sh ip bgp 69.1.0.0 | in Community
      Community: no-export
R3#sh ip bgp 69.2.0.0 | in Community
      Community: 200:100
R3#sh ip bgp 69.4.0.0 | in Community
R4

R4#sh ip bgp | in 69
 *>  69.2.0.0/16      3.3.3.3                                0 101 65837 ?
 *>  69.4.0.0/16      3.3.3.3                                0 101 65837 ?
R4#

R3#sh ip bgp 69.2.0.0 | in Community
      Community: 200:100


Case  2:-

Now we want to advertise 69.1.0.0 to R4 and change community of 69.2.0.0 from 200:100 to 300:400

R3

****To match community , Community list is must**
ip community-list 10 permit 200:100

access-list 10 permit 69.1.0.0 0.0.255.255

route-map Commchange permit 10
 match community 10
 set community 300:400

!
route-map Commchange permit 20
 match ip address 10
 set community none
!
route-map Commchange permit 30
router bgp 101
neighbor 1.1.1.1 route-map Commchange in

R3#sh ip bgp | in  69
 *>i 69.1.0.0/16      1.1.1.1                  0    100      0 1.301 ?
 *>i 69.2.0.0/16      1.1.1.1                  0    100      0 1.301 ?
 *>i 69.4.0.0/16      1.1.1.1                  0    100      0 1.301 ?
R3#
R3#sh ip bgp 69.1.1.0 | in Community
    No community attached now with 69.1.0.0
R3#sh ip bgp 69.2.1.0 | in Community
      Community: 300:400
R3#sh ip bgp 69.4.1.0 | in Community
R3#

R4

We can see 69.1.0.0 in R4

R4#sh ip bgp | in 69
 *>  69.1.0.0/16      3.3.3.3                                0 101 65837 ?
 *>  69.2.0.0/16      3.3.3.3                                0 101 65837 ?
 *>  69.4.0.0/16      3.3.3.3                                0 101 65837 ?
R4#
R4#sh ip bgp 69.1.0.0
BGP routing table entry for 69.1.0.0/16, version 39
Paths: (1 available, best #1, table default)
  Not advertised to any peer
  Refresh Epoch 1
  101 65837
    3.3.3.3 from 3.3.3.3 (39.1.4.1)
      Origin incomplete, localpref 100, valid, external, best
      rx pathid: 0, tx pathid: 0x0

R4#sh ip bgp 69.2.0.0
BGP routing table entry for 69.2.0.0/16, version 41
Paths: (1 available, best #1, table default)
  Not advertised to any peer
  Refresh Epoch 1
  101 65837
    3.3.3.3 from 3.3.3.3 (39.1.4.1)
      Origin incomplete, localpref 100, valid, external, best
      Community: 300:400
      rx pathid: 0, tx pathid: 0x0