Ahh, I did indeed mean to suggest that you filter at the ingress ASBR (the
one that creates the type 5 in the first place)  Type 5's are unmodified
throughout the AS and thus there is no mechanism within the protocol to
control their flow between areas.  However, I'm confused as to why you need
the full specifics advertised to the area and only the summary to the rest
of the AS.  Even if you have multiple customer networks attached to the
ASBR, you are still going to pull traffic destined toward them to the ASBR
via the aggregate.  What are you gaining by not using the summary address
command on the ASBR?


*********** REPLY SEPARATOR  ***********

On 7/18/2001 at 3:34 PM [EMAIL PROTECTED] wrote:

>hi all,
>
>thanks for all the replies - gave me some stuff to chew over
>
>have been looking into this some more - it's still bugging me.
>
>my investigations revealed:
>
>* making the area stub or total-stub will not work as type-5s are not
>permitted in the area.  all routers set E=0 in the options field to denote
>stub, and won't talk to non-stub neighbors.  no fooling them apparently...
>
>* summary-address will only summarize external routes originated on that
>local router - hence cannot use to summarize for non-local type-5s
>
>I cannot believe that it is not possible to do something as simple as this
>without resorting to multiple OSPF instances and redistributing between
>them!!
>
>cheers
>
>Andy
>
>Peter Van Oene wrote on July 13, 2001 at 6:43 PM:
>
>
>> Making the area stub will explicitly deny the use of type 4/5 in the
>area,
>> hence, this should not work.  Summarization at the ABR would make the
>most
>> sense to me.  Odd that it doesn't seem to work.
>>
>> pete
>>
>> *********** REPLY SEPARATOR  ***********
>>
>> On 7/12/2001 at 6:40 PM John Neiberger wrote:
>>
>> >Could you accomplish this by making the area containing the ASBR a
>> >stubby area?  IIRC, you can put an ASBR inside a stubby area but the
>> >Type-5 LSAs will not leave the area.  I'm not sure about that, but I'd
>> >swear I read that somewhere recently.
>> >
>> >Okay, I just checked this in Giles, 2nd edition.  According to him, the
>> >above is true.  But who knows if it works in the real world.
>> >
>> >Good luck!
>> >
>> >John
>> >
>> >>>> "[EMAIL PROTECTED]"
>> > 7/12/01 1:58:11 PM >>>
>> >hi all,
>> >
>> >have a problem that has been nagging at me for a good long time now...
>> >
>> >say you have a pair of ABRs sitting at an OSPF area boundary, and an
>> >ASBR is
>> >originating Type-5 LSAs from inside the non-backbone area.  Is there an
>> >easy
>> >way to suppress the propagation of the type-5s outside the area?  I
>> >would
>> >have a range statement on the ABRs to advertise the area aggregate, I
>> >just
>> >want to suppress the more specifics.
>> >
>> >I have tried using 'distribute-list out ' which would do it for
>> >me, but for some reason IOS won't allow this with OSPF:
>> >
>> >router(config)#router os 1
>> >router(config-router)#distribute-list 1 out FastEthernet 0/0
>> >% Interface not allowed with OUT for OSPF
>> >router(config-router)#
>> >
>> >I suppose that allowing this could potentially screw up routing if
>> >done
>> >without some care, but JunOS lets you do exactly this sort of thing -
>> >you
>> >can produce some wacky policies, but at least you have the option ;-)
>> >
>> >btw - I know I could prolly do this with multiple OSPF instances and
>> >redistribute between them, but I *really* don't want to get into this
>> >level
>> >of complexity.
>> >
>> >thanks in advance - this one has been driving me mad
>> >
>> >Andy




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