At the beginning of the BGP peering establishment, the BGP neighbors agree on the hold time value (included in OPEN message): the time a peering would be maintained without the reception of a KEEPALIVE or UPDATE…
The BGP synchronization rule requires that when a BGP router receives information about a network from an IBGP neighbor, it does not use that information until a matching route is learned via an IGP or static route.
What does it mean a matching route in this statement? Same prefix? Next-hop? Etc.
AS-Override feature applies to sites that have the same AS number and are linked by another AS number.
In BGP, loop prevention would prevent any site from learning other site routes due to the presence of the same AS number in the AS_PATH of the advertised routes.