Re: OSPF Summarization

See. in OSPF the summariztion is done on the ABR. Area Border Routers.
Ie Routers having the interfaces in 2 diff areas.
say R0 S0/0 is in a0 and s0/1 is in a1. now...u can give area 1 range
10.1.0.0 255.255.0.0 in R0 so that... when the 10 series a 1 route is
advertised in a0 it will be advertised as a summary rather than all
the networks with thier individual subnets.! similarly. you can
summarize area 0 routes too. basically Inter Area routes get
summarized. and is shown as IA in the routing table.

is it clear? correct me if i am wrong!
Thanking You

Yours Sincerely

Divin Mathew John
divinjohn_at_gmail.com
divin_at_dide3d.com
http://www.dide3d.com
+91 9945430983
+91 9846697191
+974 5008916
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Sent from Bangalore, KA, India

On Wed, Apr 15, 2009 at 12:34 AM, Ryan West <rwest_at_zyedge.com> wrote:
> I would like for someone to comment on this too, I feel a little green in this area. Here is my understanding though, you can only summarize with the range command for common area's. Area 0 for example cannot summarize for area 1 and 2.
>
> So..
> 1) yes they should belong to the same area
> 2) no, it will not and this applies to ipv6 as well.
>
> -ryan
>
> -----Original Message-----
> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of Naveen
> Sent: Tuesday, April 14, 2009 2:56 PM
> To: Divin Mathew John
> Cc: Salah ElShekeil; Paul Adams; Cisco certification
> Subject: Re: OSPF Summarization
>
> Group,
>
> Am a little lost with the "area range" command. When the cmd is specified
> under OSPF on an ABR -
>
> 1) Should the individual prefixes all belong to the same area ?
> 2) What happens if ABR summarizes prefixes belonging to different area ?
>
> -Naveen.
>
>
>
>
> On Tue, Apr 14, 2009 at 11:42 AM, Divin Mathew John <divinjohn_at_gmail.com>wrote:
>
>> Salah is more specfic. i kinda did the broad summarize.! do the specific
>> one!
>> Thanking You
>>
>> Yours Sincerely
>>
>> Divin Mathew John
>> divinjohn_at_gmail.com
>> divin_at_dide3d.com
>> http://www.dide3d.com
>> +91 9945430983
>> +91 9846697191
>> +974 5008916
>> PGP PUBLIC KEY BLOCK @ http://www.dide3d.com/divin_Public_PGP_key.txt
>> Sent from Bangalore, KA, India
>>
>>
>> On Wed, Apr 15, 2009 at 12:09 AM, Salah ElShekeil
>> <salah.elshekeil_at_gmail.com> wrote:
>> > area XX range 10.80.22.0 255.255.192.0
>> >
>> >
>> > try it
>> >
>> > HTH
>> >
>> > Salah
>> >
>> > On Tue, Apr 14, 2009 at 9:34 PM, Paul Adams <ccie.paul_at_gmail.com> wrote:
>> >
>> >> Hi GS,
>> >>
>> >> Perform OSPF Summarization
>> >>
>> >> L22 = 10.80.22.1/24
>> >> L32 = 10.80.32.1/24
>> >> L47 = 10.80.47.1/24
>> >>
>> >> show these routes as one....other routers should see them as single
>> >> routes..
>> >>
>> >> can someone check if the solution is correct
>> >>
>> >> (ANS)
>> >>
>> >> //summarized routes in ospf
>> >> router ospf 1
>> >> network 10.80.60.1 0.0.0.0 area 0
>> >>
>> >> <R1>
>> >> area 10 range 10.80.0.0 255.255.255.0
>> >>
>> >>
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Received on Wed Apr 15 2009 - 00:37:25 ART