RE: difference between two OSPF area types

From: Michael Zuo (mzuo@ixiacom.com)
Date: Fri Nov 10 2006 - 21:22:40 ART


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]
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> 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



This archive was generated by hypermail 2.1.4 : Fri Dec 01 2006 - 08:05:46 ART