From: Mas Kato (tealp729@xxxxxxxx)
Date: Sun Jun 10 2001 - 17:55:17 GMT-3
It's true. The 'summary-address' command is used to summarize external
networks into OSPF, just as documented (amazing, but true). It only
appears to work in the opposite direction under certain circumstances
when mutually redistributing subnets of the same major net and the OSPF
subnets are more specific than the external AS' subnets. Filtering
during the redistribution influences whether or not it will work.
If you tried to use it when the OSPF subnets are less specific than the
external AS' subnets, at best it will simply not work (the summaries
will have an impossibly high metric or -1), at worst it will black-hole
the routes to null0 (the null0 routes will be more specific than the
real routes).
As many others have explained (Roman most recently, also examples on CCO
and in the archives), when the OSPF routes are less specific (they're
already "summarized"), you're pretty much stuck with: installing
multiple static routes that lead into the less specific domain (for
example, /28 - /26 = 2 bits = 4 /28 static routes) and redistributing
these into your more specific domain, injecting a default route or
network into the more specific domain or implementing policy routing...
Mas
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Brian
Sent: Sunday, June 10, 2001 12:52 PM
To: Roman Rodichev
Cc: michael_lee50@hotmail.com; padhu@steinroe.com;
ccielab@groupstudy.com
Subject: Re: IGRP with /28 and ospf with /25, 26 , 27, 28,29,30 -
Redistributi on problem
On Sun, 10 Jun 2001, Roman Rodichev wrote:
> it's simplier than that. If you have /24 OSPF route in your routing
table,
> you can't "summarize" it (that term looses it's meaning actually) down
to
> /25 using area-range
>
> And, by the way, I'm sorry I made a mistake. summary-address can't be
used
> for OSPF->IGP summarization at all. Sorry
hmm, Roman are you sure about that last statment? If I have /28's or
/26's in my OSPF and would like them to appear in my other IGP's as
/24's
instead, why can't I use summary-address? The purpose of
summary-address
is to summarize from OSPF->non-OSPF IGP's. Perhaps I am confused about
something........
Brian
>
>
> >From: "michale_lee50@hotmail.com" <michael_lee50@hotmail.com>
> >To: "Roman Rodichev" <rodic000@hotmail.com>, <padhu@steinroe.com>,
> ><ccielab@groupstudy.com>
> >Subject: Re: IGRP with /28 and ospf with /25, 26 , 27, 28,29,30 -
> >Redistributi on problem
> >Date: Sun, 10 Jun 2001 13:45:10 -0500
> >
> >scenario. I just need a way to inject the ospf /25 thro /30 as /28
into
> >IGRP...?? This is your question
> >
> >I have to say that is a strange one. Maybe I'm geting a little too
old but
> >I
> >am under the impression that you want to redistribute a /28 into IGRP
?
> >mayby you want to redistribute an ospf network that is directly
connected
> >into IGRP but that network is not downstrean so you can's use
area-range
> >and
> >it's not coming into ospf so you can's use summary addres?
> >
> >is this the case?
> >
> >Mr.Lee
> >
> >----- Original Message -----
> >From: "Roman Rodichev" <rodic000@hotmail.com>
> >To: <michael_lee50@hotmail.com>; <padhu@steinroe.com>;
> ><ccielab@groupstudy.com>
> >Sent: Sunday, June 10, 2001 1:02 PM
> >Subject: Re: IGRP with /28 and ospf with /25, 26 , 27, 28,29,30 -
> >Redistributi on problem
> >
> >
> > > Mr.Lee, you can't use summary-address and area range commands to
go from
> > > shorter to longer bit mask.
> > >
> > > >From: "michale_lee50@hotmail.com" <michael_lee50@hotmail.com>
> > > >To: "Roman Rodichev" <rodic000@hotmail.com>,
<padhu@steinroe.com>,
> > > ><ccielab@groupstudy.com>
> > > >Subject: Re: IGRP with /28 and ospf with /25, 26 , 27, 28,29,30 -
> > > >Redistributi on problem
> > > >Date: Sun, 10 Jun 2001 12:56:20 -0500
> > > >
> > > >Guess I'm sort of late on this but I have to say that Policy
routing is
> > > >certainly NOT the only way, you can accomplish this with the
> > > >summary-address
> > > >or the area-range in a given situation.
> > > >
> > > >Just hit the link and understand where and when to apply each
command.
> > > >
> > > >Mr.Lee
> > > >----- Original Message -----
> > > >From: "Roman Rodichev" <rodic000@hotmail.com>
> > > >To: <padhu@steinroe.com>; <ccielab@groupstudy.com>
> > > >Sent: Friday, June 08, 2001 10:58 PM
> > > >Subject: Re: IGRP with /28 and ospf with /25, 26 , 27, 28,29,30 -
> > > >Redistributi on problem
> > > >
> > > >
> > > > > you are wasting your time, policy routing is the only solution
> > > > >
> > > > > >From: "Padhu (LFG)" <padhu@steinroe.com>
> > > > > >Reply-To: "Padhu (LFG)" <padhu@steinroe.com>
> > > > > >To: "'ccielab@groupstudy.com'" <ccielab@groupstudy.com>
> > > > > >Subject: IGRP with /28 and ospf with /25, 26 , 27, 28,29,30 -
> > > >Redistributi
> > > > > >on problem
> > > > > >Date: Thu, 7 Jun 2001 21:49:24 -0500
> > > > > >
> > > > > >I know we have beaten the crap out of VLSM / FLSM scenario.
Its
> >working
> > > > > >fine
> > > > > >with IGRP /24 and ospf having longer masks ...( with area
ranges
> >and
> > > > > >summary
> > > > > >addresses blah blah etc) ..
> > > > > >
> > > > > >Now the reverse ...I know i can plug in the ip default
network for
> >this
> > > >and
> > > > > >will work. However i am wondering if anyone on the list has
got
> >this
> > > > > >working
> > > > > >without ip default network for this scenario. Summary-address
and
> >area
> > > > > >ranges are so out of whack here i can't get this straight in
this
> > > >reverse
> > > > > >scenario. I just need a way to inject the ospf /25 thro /30
as /28
> >into
> > > > > >IGRP...
> > > > > >
> > > > > >No Statics ofcourse.
> > > > > >
> > > > > >Appreciate any help. My ASBR is running 12.0(14).
> > > > > >
> > > > > >Or you can simply tell me i am wasting time to do the
impossible
> >...(
> > > > > >Ofcourse i can't tell the proctor that)
> > > > > >
> > > > > >Cheers,Padhu
> > > > > >**Please read:http://www.groupstudy.com/list/posting.html
> > > > >
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