[c-nsp] Difference between ISIS NSR and ISIS NSF Cisco-Style

[Dhamija Amit]

Hi 
 
I would like to know the difference between actuall ISIS NSR and ISIS NSF cisco style.
 
Most documentation says they are same , however thereare some differences also and it's not real  NSR. Also i have seen in some packet sniffer in cisco style cisco router sends a dummy special CSNP packet to neighbour to get all the valid LSP's in database.
 
Will NSR also depends upon some refresh information from Neighbours ??
 
Thanks,
Amit Dhamija