From: Chua, Parry (Parry.Chua@xxxxxxxxxx)
Date: Thu May 02 2002 - 23:00:01 GMT-3
My understand is that area x (include 0) range will work on any ABR, but you ne
ed to know the area concepts of OSPF. If R3 only in area 0, then it is not a AB
R. If you allow to create a dummy area at R3, then it become a ABR, area 0 rang
e will work.
When you do area 0 range at a ABR, it will only summary into the other area whe
re the ABR is attach. For example, if R3 has area 123 and area 0, area 0 range
at R3 will has area 0 summary into area 123 only. If you do area 123 range at R
3, it will pass the summary to area 0 and other areas except arae 123.
> Parry Chua
>
>
-----Original Message-----
From: Katson PN Yeung [mailto:kyeung@hkcix.com]
Sent: Friday, May 03, 2002 9:30 AM
To: ccielab@groupstudy.com
Subject: Solie's P.791 confusion.
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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