From: Michael Zuo (mzuo@ixiacom.com)
Date: Mon Nov 13 2006 - 22:24:33 ART
Thank you all for your responses...
I lab'ed it up and now clear on the two commands.... Basically the
"no-redistribute" prevents redistribution on the local router but
redistributed routes can still come in from other ASBR. This is not
possible for stub...
________________________________
From: Elias Chari [mailto:elias.chari@gmail.com]
Sent: Friday, November 10, 2006 5:33 PM
To: Michael Zuo
Cc: Ian Blaney; Angelo De Guzman; Adhu Ajit; ccielab@groupstudy.com
Subject: Re: difference between two OSPF area types
Hi Michael,
Look at the requirement (assuming the ccie lab) and decide what area
type you need. If the task has some restrictions on the type of routes
an area should receive, the objective may be met by both stub or nssa,
but then you may be asked (towards the end of your ospf section..-) to
redistribute a connected interface, static route(s) or another protocol
from within that area.
Remember the main difference between stub and nssa. NSSA supports an
ASBR, whilst stub areas do not. Now ask yourself what area type will it
meet the above objectives?
HTH
Elias
On 11/11/06, Michael Zuo <mzuo@ixiacom.com> wrote:
Hi Guys, thanks for the replies.
Unfortunately, I am getting more confused :-) sorry about being so slow.
If I configure "area 1 stub no-summary", the area will only have type 1,
2 LSA plus one type 3 default route
If I configure "area 1 nssa no-summary no-redistribution", "no-summary"
will block out type 3 LSA except one default route. "no-redistribution"
will block out type 7 LSA. What is left is type 1, 2 and one type 3
default route.
As this point two command will yield the same types of LSAs, wouldn't
they be equivalent?
thanks
________________________________
From: Ian Blaney [mailto: ian.blaney@gmail.com
<mailto:ian.blaney@gmail.com> ]
Sent: Friday, November 10, 2006 1:22 AM
To: Michael Zuo
Cc: ccielab@groupstudy.com
Subject: Re: difference between two OSPF area types
Michael
When an ABR is also an ASBR and is connected to a NSSA the default
behavior is to send redistributed
routes into the NSSA.
With the no-redistribution option redistribution will be turned off on
the ABR/ASBR into the NSSA. The no-summary will send a type 3 default
route into the NSSA and block the flooding of type 3 and type 4 LSAs
into the NSSA
I hope the diagram below is readable. R1 is an ABR for the OSPF NSSA
area and also an ASBR for the redistributed RIP routes from R2. The
no-redistribution option will prevent the redistributed RIP routes being
advertised into the OSPF NSSA area.
OSPF
R1 NSSA R3
RIP
R2
Ian
On 11/10/06, Michael Zuo < mzuo@ixiacom.com <mailto:mzuo@ixiacom.com> >
wrote:
Hi Group,
Anyone knows the difference between:
Area 1 nssa no-summary no-redistribution
And
Area 1 stub no-summary
To me, they seem to be the same thing...
thanks
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