Hello Mohammad
BGP does use triggered updates when it learns of a change on its internal domain. However, there are a few things that affect the operation of this triggering that will in turn affect the behaviour of BGP.
Lets say that there is a network on the internal domain that is learned via OSPF, and this network continually goes up and down. BGP updates will be affected by the following:
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The detection of the changes - how fast does the router detect that the OSPF route is down? This depends primarily on the BGP scanner process. This process walks the BGP table and confirms reachability of the next hops. The most important issue here is that BGP will do this once a minute.
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Propagation of the changes - How fast and often can BGP advertise the changes? By default, BGP waits for the Advertisement Interval to expire before sending any changes. For eBGP, the default is 30 seconds and for iBGP the default is 5 seconds. Even if a change is detected in an OSPF route for example, BGP will not send out any advertisements until this timer expires. The benefit is that updates can be sent more efficiently, solving the problem of stability to a certain degree, but this comes at a cost of convergence time.
If however you have a flapping route on an internal network, BGP will not issue updates at the same frequency thus giving you some stability until the problem can be solved.
I hope this has been helpful!
Laz