[c-nsp] OSPF router gets separated from a broadcast domain

[Gabor Ivanszky]

Dear all,

I did some research in different OSPF literature, and couldn't find any 
solution for the following simple-looking issue:

Let's assume you have a broadcast multi-access network(e.g. ethernet) 
with a subnet living on it, and having multiple OSPF routers connected 
to it. Let's go with two routers for the example. As long as the 
broadcast domain is intact, everything is fine, one of the OSPF routers 
is the DR, and the other is the BDR, and only the DR announces the 
network of this broadcast domain in it's LSA.

Now one of the routers gets separated from the network, while it's 
physical interface remains in "up" state, which is easily possible 
especially with ethernet. Now the routers can not see each other, so 
both of them became DR, and start to announce the network. The problem 
is with the announcement of the separated router, which could 
potentially create a black-hole in the network.

It is hard to believe, that OSPF is not able to handle a situation like 
this.

regards,
Gabor