From: Perminder Grewal (percy_gunner@xxxxxxxxxxx)
Date: Fri May 03 2002 - 03:17:03 GMT-3
Can anyone help
I tried this scenario in my lab yesterday the basic set up is the same as
yours.
> R4
> |s0
> |
> --s0.1---| R1---|e0
>|e0-R3< /
> --s0.2---------<
> \
> R2---|e0
1) the frame is a /29 area 0 (r3 r2 r1)
2) R1 and R2 are ABR area 0 and area 1 (e0) /25
3) R3 to R4 is a /24 igrp. ASBR (area 0 and IGRP)
A) I can summarise the /25 to a /24 and the routers R1 and R2 have a null0
in the route table and R4 gets the /24 from area 1.
B) I've done the same on R3 summarise /29 to a /24 this does not put in a
null0 in the R3 route table and in doing so does not advertise that prefix
to R4.
Solution??????
I tried the the summ on R1 and R2 for area 0 it puts in the /24 nullO in
there route table but R3 does not have it and in doing so does not advertise
to R4.
I got over the problem by including a static route /24 in R3 to null0 and
then redistributed that static to in IGRP in doing so R4 gets the /24 for
area.
If anyone can shed any light, please let me know. I tried every combo last
night and could only do this by the static method.
Cheers
Percy
>From: Katson PN Yeung <kyeung@hkcix.com>
>Reply-To: Katson PN Yeung <kyeung@hkcix.com>
>To: ccielab@groupstudy.com
>Subject: Solie's P.791 confusion.
>Date: Fri, 03 May 2002 09:29:31 +0800
>
>Dear group,
>
>I have a question about Solie's book P.791.
>
>On the 2nd paragraph from the top, it saids:
>"You cannot summarize Area 0 or the backbone area. All summaries are
>flooded into area 0 and then are flooded out from that point. Therefore
>Area 0 routes cannot be summarized"
>
>However, in the scenario such as below:
>
> R4
> |s0
> |
> --s0.1---| R1---|e0
>|e0-R3< /
> --s0.2---------<
> \
> R2---|e0
>
>Where R3s0.2, R1s0, and R2s0 forming OSPF area 0 (/28 subnet)
>- R1e0 area 1 (/24)
>- R2e0 area 2 (/24)
>- R3e0 being area 3 (/24 or whatever)
>- R3 s0.1 and R4 running igrp (/24)
>
>Isn't it easy (and convenient) to create a /24 summary route by "area 0
>range x.x.x.x 255.255.255.0" at R3, and then get it redistributed to igrp?
>I did they before since the redis connected/summary ASBR method doesn't
>work now.
>
>Solie P.791 makes me confused. Can someone clarifies if this "area 0
>range" method is "okay to use" in the real lab environment?
>
>Or just like someone saids, tunnel method, sec interface method? or even
>piggy-back OSPF
>method are the more preferable way to make a /24 summary route?
>
>Thanks a lot.
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