Synchronization
In Cisco IOS, BGP does not advertise a route before all routers in the AS have learned it via an IGP
- This is a default which is unhelpful to most ISPs
Disable synchronization if:
- AS doesn’t pass traffic from one AS to another, or
- All transit routers in AS run BGP, or
- iBGP is used across backbone
You should always use iBGP
- so, always use “no synchronization”