RE: Internetwork Expert Volume 2 Lab 7 Task 4.7

As Naveen has already said, the type 3 summary is coming from R5, then when R1 is part of area 0, it has all of the type1 LSA's of area 0, including both of the loopbacks. This is why it needs to be summarized again at R1. This lab is a good exercise in OSPF, there is another good example of summarization when you get to SW3 and SW4's range command, it's interesting to see that the range command is only affects the ABR's entry point into area 0 and not all other summaries that flow through it.

-ryan

-----Original Message-----
From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of Naveen
Sent: Monday, April 06, 2009 3:59 AM
To: Vincent Tay
Cc: Ccielab_at_groupstudy.com
Subject: Re: Internetwork Expert Volume 2 Lab 7 Task 4.7

Vincent,

I had the same problem. When the virtual link came up, R1 leaks the
loopbacks of R4 and R5 back to R3 that was previously summarized. Hence
virtual link is not a good solution.

Virtual link is considered part of Area 0 and hence R1 would receive both
loopbacks without summarization. Next, R1 sends it to R3 breaking the
summarization done earlier.

HTH

On Mon, Apr 6, 2009 at 12:40 AM, Vincent Tay <vtay.75_at_gmail.com> wrote:

> Hi all,
>
> I need some enlightenment. For Internetwork Expert Volume 2 Lab 7 Task 4.7,
> i have configured virtual link (Area1) between router R1 and R5. R5 was
> summarise some of the Area0 routes. When the virtual link is up, the routes
> was not summarise. Anyone know why and how it happen and how virtual link
> work in deep technical? GRE tunnel solve the issue.
>
> Area0 Area1 Area1 Area2
>
> R4---------------------->R5---------------->R3-------------->R1----------------->R2
>
> Regards
> Vincent Tay
>
>
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Received on Mon Apr 06 2009 - 08:59:30 ART