said by josephf:I believe this is true in some cases. I believe "technically" the called number is looked up in an LNP database which as someone else pointed out provides an LRN. That database doesn't necessarily reside with the original CLEC. When I worked in the industry (10+ years ago) porting was not possible but was being discussed/formulated. As such I'm certainly no expert regarding SS7 today. I was just attempting to illustrate what goes on behind the scenes when a call is placed.
If understanding you correctly, the original LEC from whom the number was ported-out from can interfere and stop (whether due to equipment disaster or sabotage) all callers from reaching the destination DID. This is true even though the original LEC has no customer or business relationship with either the end telephone subscriber or his current LEC.