Well I just took the "Do I know this already" quiz on multi-area OSPF in my BSCI textbook. I got most of the questions right, some I got rightfully wrong, but others I got wrongfully wrong.
Here are my objections:
Q3: Which of the following statements explain why this feature (use of areas) is such an important enhancement on earlier routing protocols?
The two "correct" answers include "B" (area summarization reduces routing table size & spf calculations), and "D" which reads: "The use of multiple areas allows for the use of prioritization."
Prioritization? That's an interface/DR election thing, not an areas thing. How could that be listed as a correct answer?
Q8: Which of the following conditions must be met before any LSAs can be flooded out of all the interfaces?
"A" "B" and "C" are all correct. A = Exchange or Full state, B = interface not connected to totally stubby area, C = LSA not received on same interface.
A and C I'm cool with. But isn't it messy to say "interface must not be connected to a totally stubby area" when the question didn't specify that we were dealing with LSA's that aren't Type 1 or 2; it also didn't specify that we were talking about an ABR/ASBR. Type 1 and Type 2 LSA's still get flooded throughout the area they originate in, even if it's a totally stubby area, right? So an internal router (in exchange or full state) in a total stub area gets a Type 1 or 2 LSA, it will flood those LSA's out all its other interfaces, won't it? If so, then that question was poorly put together. Nice going.
Q9: Which of the following affect how the routing table is created?
Correct answers are "A" ("Whether there are multiple areas in the domain"), "C" ("The type of area where the router is"), and "D" ("Whether there are communications outside the AS.")
I say that "A" doesn't affect the ROUTING table, but rather the TOPOLOGY table. Area-ness doesn't necessarily impact the cost of the routes; the RT just has to put an "IA" on the screen. Interarea routes have the same AD, don't they? And the same goes for "C" - the type of area determines which LSA's are allowed in, that in turn affects the TOPOLOGY table, not the routing table. The RT is built from the topology table, and by the time the topology table is built, we're done looking at area types.
"D". Yeah, I'll grant them that (E1 and E2 routes and all). Still the question is enragingly vague.