Bob,
I'll try to answer your first question below at the expense of possibly
clouding the issue:
*Question: Does this mean that each router within the area picks the
closest ABR as the gateway to everything outside the area,...
Well...Yes! OSPF first takes the "shortest path" to area 0.
For instance in the diagram below can you predict the path from A to B?
(Rtrs A,B,C,and D are all area border routers)
RtrE-
| \ T1
| \
T1 RtrC---56k---RtrA___|A
| | | |
| | |
RtrF T3 Area0 T3 Area1
| | |
|Area2 | |
T1 RtrD---T3----RtrB
| /
| / T1
RtrG- /
|
---
B
NOTE: This example is taken from the CCIE Power Session on OSPF which I
attended at Networkers 2000 in Vegas...Presented by Dr William Parkhurst
Answer: A-->C-->E-->F-->G
The path is derived from these rules:
1) Shortest path to area 0
2) Shortest path across area 0 without going through a non-zero area
3) Shortest path to B without going through area 0
Your second part
*Question Cont.: ...and that there is no way to control the default
route?
I'm not sure if you can control the default route inthe above scenario
(which I provided)...If you want to deviate from the above behavior
tweaking the "area default-cost" may do it though...assuming of course A
had been connected to both A and B routers (or somewhere else behind
RtrA giving it some other option toward RtrB) which would NOT circumvent
the above rules. I'm curious though...and I'll try to research this if
I can find enough available routers.
Sorry I may not be of much help here but I'm currently concentrating on
the CCIE lab where you are NOT permitted to use "static routes (of any
kind) or Default routes" unless of course explicitly told to do so.
I'll store away the possibility of using the "area default-cost" as a
potential possiblity though...thanks.
Here's another quote I made note of while in the CCIE Power Session
which may be of help to the group:
"The Routing and Switching exam tests your ability to apply
configuration knowledge and skill to new situations. It is not a design
test, or a test of "best pratices" for use in the field."
Just FYI for others preparing for the lab. Hope this helps...Thanks and
aloha, Frank
Bob Hunter wrote:
>
> Hi,
> I'm confused on the subject of totally stubby areas, and the command "area
> default-cost". From what I'm reading, one of the qualifications of a totally
> stubby area is that if multiple exits (ABRs) exist, routing to outside the
> area does not have to take an optimal path. Does this mean that each router
> within the area picks the closest ABR as the gateway to everything outside
> the area, and that there is no way to control the default route? If so, does
> that imply that the area default-cost is used for incoming routes? Would
> incoming routes even exits if the area was a totally stubby area?
>
> I would very much appreciate it if someone would please set me straight.
>
> Thank you.
>
> Bob Hunter, CCNA, CNE
>
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