in this diagram we have same ABR and ASBR,this router functions as an ABR between area 1 and zero,plus it works as an ASBR and redistribute external routes from some other routing domain to OSPF domain, so the question is:
- why do we need to have an NSSA in here? I mean this router has got one interface in Area 0 and one in Area 1,and one in some other routing domain,it does not belong to a particular area(does not have all its interfaces in one single,individual area)so waht's the reason to have a NSSA in here?and if we are supposed to have NSSA which area will be that?
refereed to this document http://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/6208-nssa.html in which talks about "Bit P" and it says "This happens when NSSA ASBR is also an NSSA ABR." so why on the earth in this case do we need to have NSSA? it's so confusing.