11gR2 dataguard realtime apply.

A question about 11gR2 dataguard realtime apply -

1, I understand that if the real time apply can't catch up with redo rate, it will be downgraded to archivelog, but is there a timeout for this ?

2. if there is a network problem and primary can't tranfer the log and do realtime apply. is there a time out for primary to downgrade it to archive apply ?

For above 2 cases. during the time out period. primary will be "hanging", is that correct ?

Thanks

Brian