Options
Synch issue in BGP
O R4<
|
|
|
|
| 14.0.0.0/8----eBGP
|
|
O R1<
|iBGP
|
|
| 13.0.0.0/8
|
|
O R3
|
|
| 23.0.0.0/8
|
|
O R2<
|iBGP
|
|
| 25.0.0.0/8
eBGP
|
|
O R5<
|
The pic is confusing a little but its easy to understand once i explain.
R4 is in BGP AS 4, and forming eBGP connection to R1.
R1 and R2 are in BGP AS 1 and forming iBGP connection trough R3 (which is not running BGP). R1, R2 and R3 are also running OSPF, so R1 and R2 are able to form connection.
R5 is in BGP AS 5 and forming eBGP connection to R2.
Now, R4 is advertising 14.0.0.0 via BGP network statement, and so is R5 advertising 25.0.0.0. Simple.
When i type "no synch" under BGP process of R1 and R2, they install routes in BGP table as best just as they were suppose to.
But now when i type "synch" under R1 and R2 (and also run OSPF on 14.0.0.0 and 25.0.0.0 interfaces of R1 and R2) it doesn't work!!
This is output after turning synch on:
This is R3:
C 23.0.0.0/8 is directly connected, Serial1/3
O 25.0.0.0/8 [110/65] via 23.0.0.2, 01:04:29, Serial1/3
C 13.0.0.0/8 is directly connected, Serial1/2
O 14.0.0.0/8 [110/65] via 13.0.0.1, 01:04:29, Serial1/2
This is R1:
O 23.0.0.0/8 [110/128] via 13.0.0.3, 01:06:14, Serial1/1
O 25.0.0.0/8 [110/129] via 13.0.0.3, 01:06:14, Serial1/1
C 13.0.0.0/8 is directly connected, Serial1/1
C 14.0.0.0/8 is directly connected, FastEthernet0/0
And R2:
C 23.0.0.0/8 is directly connected, Serial1/1
C 25.0.0.0/8 is directly connected, FastEthernet0/0
O 13.0.0.0/8 [110/128] via 23.0.0.3, 01:03:33, Serial1/1
O 14.0.0.0/8 [110/129] via 23.0.0.3, 01:03:33, Serial1/1
So notice that they all have knowledge of 25.0.0.0 and 14.0.0.0 via OSPF.
But notice BGP table now :
R1#sh ip bgp
Network Next Hop Metric LocPrf Weight Path
r> 14.0.0.0 14.0.0.4 0 0 4 i
* i25.0.0.0 23.0.0.2 0 100 0 5 i
R2#sh ip bgp
Network Next Hop Metric LocPrf Weight Path
* i14.0.0.0 13.0.0.1 0 100 0 4 i
r> 25.0.0.0 25.0.0.5 0 0 5 i
What am i missing? Why aren't those routes treated as best?
Notice:
R1#sh ip bgp 25.0.0.0
BGP routing table entry for 25.0.0.0/8, version 6
Paths: (1 available, no best path)
Not advertised to any peer
5
23.0.0.2 (metric 12
from 23.0.0.2 (25.0.0.2)
Origin IGP, metric 0, localpref 100, valid, internal, not synchronized
Says its not synchronized? Same with 14.0.0.0 on R2.
Can anyone shed some light on this please?
|
|
|
|
| 14.0.0.0/8----eBGP
|
|
O R1<
|iBGP
|
|
| 13.0.0.0/8
|
|
O R3
|
|
| 23.0.0.0/8
|
|
O R2<
|iBGP
|
|
| 25.0.0.0/8
eBGP
|
|
O R5<
|
The pic is confusing a little but its easy to understand once i explain.
R4 is in BGP AS 4, and forming eBGP connection to R1.
R1 and R2 are in BGP AS 1 and forming iBGP connection trough R3 (which is not running BGP). R1, R2 and R3 are also running OSPF, so R1 and R2 are able to form connection.
R5 is in BGP AS 5 and forming eBGP connection to R2.
Now, R4 is advertising 14.0.0.0 via BGP network statement, and so is R5 advertising 25.0.0.0. Simple.
When i type "no synch" under BGP process of R1 and R2, they install routes in BGP table as best just as they were suppose to.
But now when i type "synch" under R1 and R2 (and also run OSPF on 14.0.0.0 and 25.0.0.0 interfaces of R1 and R2) it doesn't work!!
This is output after turning synch on:
This is R3:
C 23.0.0.0/8 is directly connected, Serial1/3
O 25.0.0.0/8 [110/65] via 23.0.0.2, 01:04:29, Serial1/3
C 13.0.0.0/8 is directly connected, Serial1/2
O 14.0.0.0/8 [110/65] via 13.0.0.1, 01:04:29, Serial1/2
This is R1:
O 23.0.0.0/8 [110/128] via 13.0.0.3, 01:06:14, Serial1/1
O 25.0.0.0/8 [110/129] via 13.0.0.3, 01:06:14, Serial1/1
C 13.0.0.0/8 is directly connected, Serial1/1
C 14.0.0.0/8 is directly connected, FastEthernet0/0
And R2:
C 23.0.0.0/8 is directly connected, Serial1/1
C 25.0.0.0/8 is directly connected, FastEthernet0/0
O 13.0.0.0/8 [110/128] via 23.0.0.3, 01:03:33, Serial1/1
O 14.0.0.0/8 [110/129] via 23.0.0.3, 01:03:33, Serial1/1
So notice that they all have knowledge of 25.0.0.0 and 14.0.0.0 via OSPF.
But notice BGP table now :
R1#sh ip bgp
Network Next Hop Metric LocPrf Weight Path
r> 14.0.0.0 14.0.0.4 0 0 4 i
* i25.0.0.0 23.0.0.2 0 100 0 5 i
R2#sh ip bgp
Network Next Hop Metric LocPrf Weight Path
* i14.0.0.0 13.0.0.1 0 100 0 4 i
r> 25.0.0.0 25.0.0.5 0 0 5 i
What am i missing? Why aren't those routes treated as best?
Notice:
R1#sh ip bgp 25.0.0.0
BGP routing table entry for 25.0.0.0/8, version 6
Paths: (1 available, no best path)
Not advertised to any peer
5
23.0.0.2 (metric 12
from 23.0.0.2 (25.0.0.2)Origin IGP, metric 0, localpref 100, valid, internal, not synchronized
Says its not synchronized? Same with 14.0.0.0 on R2.
Can anyone shed some light on this please?