bgp synchronisation

hi

the rule say If your autonomous system is passing traffic from another AS to a third AS, BGP should not advertise a route before all routers in your AS have learned about the route via IGP.

does mean that we have for exemple in minimum three AS

for exemple AS1 advertise network to AS2 ( that contain bgp router and non bgp router )

so for AS2 can advertise network to AS3 , the AS2 must have a route in igp in all router that belong to AS2

I see a blog http://ciscodreamer.blogspot.com/2009/03/bgp-synchronization.html

that guy work with only 2 AS , is that correct ?

that site http://docwiki.cisco.com/wiki/Internetworking_Case_Studies_--_Using_the_Border_Gateway_Protocol_for_Interdomain_Routing#Synchronization

explain the things differenty but must be correct

need some real lab to work in that before to do it in workbook vol1

any help in that ( lab just to understand the things well )

thanks