Any one can answer the BGP Synchronization question ?
The topology is very simple. Router2---Router1--interface e1/1(ip address 111.1.1.1/24)
R1
router bgp 12
network 111.1.1.0 mask 255.255.255.0
neighbor 2.2.2.2 remote-as 12
neighbor 2.2.2.2 update-source Loopback0
router ospf 1
network 0.0.0.0 255.255.255.255 area 0
R2
router bgp 12
synchronization
neighbor 1.1.1.1 remote-as 12
neighbor 1.1.1.1 update-source Loopback0
router ospf 1
network 0.0.0.0 255.255.255.255 area 0
R2#show ip bgp
Network Next Hop Metric LocPrf Weight Path
* i111.1.1.0/24 1.1.1.1 0 100 0 i
After R2 enabled synchronization, the network 111.1.1.0/24 in bgp table lost marker “>” in the bgp table.
Question:
In the case, synchronization rule means network 111.1.1.0/24 is inactive (meaning losing marker “>” ) in R2’ BGP table until this network goes into R2 via IGP. Now the network 111.1.1.0/24 already has gone into R2 via IGP. Why does the network 111.1.1.0/24 is still inactive in R2 BGP table after enabling synchronization in R2 ?
You can disable synchronization if one of the following conditions is true:
- Your AS does not pass traffic from one AS to another AS.
- All the transit routers in your AS run BGP.