So you are talking about a topology where you have an ASBR that also borders Area 0
and is thus also an ABR by definition.
The question is then, "can I control which external prefixes enter the rest of the
ospf domain as type 5 LSA's" I would have to say that you cannot by definition
restrict the flow of LSA's in an OSPF domain beyond turning down interfaces. You can
decide which area's will recieve Type 3/4/5/7/10 etc by the use of stub areas and
their variants and you can also minimize prefix flow's by summarizing at borders.
However, there is no way to my knowledge that you can instruct a ABR to advertise some
but not all type 5's into an area.
Route filtering in OSPF is somewhat of a misnomer in my opinion. Since link state
protocols do not advertise their routing table, but instead their link state database,
the concept of prefix filtering within an OSPF domain is out of place. In fact,
filting LSA's of any kind within an area directly violates the RFC in that all routers
in an Area MUST maintain identical copies of the area topology. However, filtering
type 5's at the ABR, to me, has some merits. I may be missing something here and
Howard will likely point it out if I am. But in summary, there is no
"distribute-list" type command that allows you to restrict the flow of LSA's within an
OSPF domain.
Naturally I'm sure your aware that you can filter prefixes like mad when dealing with
redistribution into or out of OSPF.
HTH
-pete
*********** REPLY SEPARATOR ***********
On 2/2/2001 at 7:48 AM Curtis Call wrote:
>Anything, but to make it simple lets just say we're trying to redistribute
>static routes.
>
>At 08:41 AM 2/2/01 -0500, you wrote:
>>Redistribute what?
>>
>>
>>*********** REPLY SEPARATOR ***********
>>
>>On 2/1/2001 at 8:02 PM Curtis Call wrote:
>>
>> >There's something that I'm curious about dealing with OSPF ASBRs. Let's
>> >say your ASBR is also an ABR that is bordering area 0 and area 1. Is there
>> >a way that you could specify to only redistribute into area 1 or by nature
>> >of being an ASBR does a router have to advertise the route to every area to
>> >which it is connected (assuming all areas are normal non-stub areas).
>> >
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