[c-nsp] OSPF design

[Geoffrey Pendery]

> Not true.  All /prefixes/ will still be visible in all areas without summarization, but you'll still minimize the LSDB because type 1 and 2 LSAs never cross an area boundary.

Right, but as Brett mentions, that doesn't stop them, it just turns
them into type 3s.  Sometimes it even turns a single type 1 (with stub
networks on it) to multiple type 3s.
I am curious if someone can explain any benefits to non-summarized
areas.  Perhaps there's benefit on the Dijkstra front if you have ISPF
enabled?  Perhaps the flooding model is reduced a bit by relying on a
small number of ABRs to flood the type 3s, rather than intra-area type
1 and 2 flooding?

I honestly don't know, and would like to.

> According to Jeff Doyle, control plane performance concerns are not related to  running Dijkstra, but rather lie in LSDB maintenance:  Keeping track of timers and such.

So if this is the case, it would seem the LSDB doesn't get any smaller
(with type 3's subbing in for 1 and 2), except now ABRs have to
maintain multiple LSDBs, thus doubling/tripling their burden?

-Geoff