This command has no arguments.
Purpose: IBGP learned routes are not installed in the IP routing table if the route has not been learned by an IGP or if the advertised next hop is inaccessible. This is called synchronization.
IOS Release: 10.0
In Figure 12-1, BGP synchronization is enabled by default. Router A is advertising network 188.8.131.52/24 to Router B via EBGP, and Router B is advertising 184.108.40.206/24 to Router C via IBGP.
Router A interface Loopback0 ip address 220.127.116.11 255.255.255.0 ! router bgp ...