Re: LSA Type 4 again

From: Rick Mur <rmur_at_ipexpert.com>
Date: Sun, 6 Sep 2009 20:44:03 +0200

Thanks for the explanation! I really need to work on my theory in
these kinds of things.

--
Rick Mur
CCIE2 #21946 (R&S, Service provider)
Sr. Support Engineer -- IPexpert, Inc.
Sent from my iPhone
On 6 sep 2009, at 20:18, Narbik Kocharians <narbikk_at_gmail.com> wrote:
> Rick
>
> Always look at it from the perspective of the router that originated  
> LSA type 5s, in a NSSA the ASBR originates type 7, but the ABR  
> receives type 7s and originates type 5s, therefore, area 0 will NOT  
> see LSA type 4s, but if area 0 was connected to another area, that  
> third area will receive type 4s. I think of the ABR (The one that  
> connects the NSSA to area 0) as a pseudo-ASBR. BTW i did not say  
> that this will be explained in the same manner in the RFC, just the  
> way i think of that ABR.
> On Sun, Sep 6, 2009 at 11:13 AM, Rick Mur <rmur_at_ipexpert.com> wrote:
> Wow I think this is the first time I detect an error in text from  
> Jeff Doyle, damn! he is human after all :-P
>
>
> --
>
> Rick Mur
> CCIE2 #21946 (R&S, Service provider)
> Sr. Support Engineer -- IPexpert, Inc.
>
> Sent from my iPhone
>
> On 6 sep 2009, at 18:26, Narbik Kocharians <narbikk_at_gmail.com> wrote:
>
>> LSA type 4 WILL NOT be permitted in any stub areas, as a matter of  
>> fact it won't even be in the area 0, if you have area 0 and a NSSA  
>> area, the only time you will see LSA type 4s is if you have another  
>> area (Non-zero area ) connected to area 0.
>>
>>
>> Therefore, i agree with Scott.
>>
>> On Sun, Sep 6, 2009 at 8:46 AM, Rick Mur <rmur_at_ipexpert.com> wrote:
>> That's a pretty clear explanation :-)
>>
>> --
>>
>> Rick Mur
>> CCIE2 #21946 (R&S, Service provider)
>>
>> Sr. Support Engineer -- IPexpert, Inc.
>>
>> Sent from my iPhone
>>
>>
>> On 6 sep 2009, at 17:20, Scott Morris <swm_at_emanon.com> wrote:
>>
>> "Allowed" and "will exist" are two different things.   I'll let  
>> Jeff run
>> with the idea that they're permitted in NSSA areas 'cause I like  
>> Jeff.
>> However, I will guarantee that they will not exist  in NSSA  
>> areas.  :)
>>
>> So call it whatever you want!
>>
>>
>>
>>
>> *Scott Morris*, CCIE/x4/ (R&S/ISP-Dial/Security/Service Provider)  
>> #4713,
>>
>> JNCIE-M #153, JNCIS-ER, CISSP, et al.
>>
>> CCSI #21903, JNCI-M, JNCI-ER
>>
>> swm_at_emanon.com
>>
>>
>> Knowledge is power.
>>
>> Power corrupts.
>>
>> Study hard and be Eeeeviiiil......
>>
>>
>>
>> Molomo wrote:
>> Experts,
>>
>> Jeff Doyle says LSA type 4 is allowed in nssa area ( see table  
>> below). I
>> would have thought that since LSA 5 is not permitted then no need to
>> generate LSA 4.
>>
>> My understanding is , ABR generates LSA 4 based on the type 5, to  
>> describe
>> the position of the ASBR.
>>
>>
>> Or am I missing something here?
>>
>>
>> I have also seen this in Quick Reference Sheet by Anthony Sequeira.
>>
>>
>>
>>
>>  Table 8-5. LSA types allowed per area type.
>>
>> Area Type
>>
>> 1&2
>>
>> 3
>>
>> 4
>>
>> 5
>>
>> 7
>>
>> Backbone (area 0)
>>
>> Yes
>>
>> Yes
>>
>> Yes
>>
>> Yes
>>
>> No
>>
>> Non-backbone, non-stub
>>
>> Yes
>>
>> Yes
>>
>> Yes
>>
>> Yes
>>
>> No
>>
>> Stub
>>
>> Yes
>>
>> Yes
>>
>> No
>>
>> No
>>
>> No
>>
>> Totally stubby
>>
>> Yes
>>
>> No[*]<mk:@MSITStore:C:\Documents%20and%20Settings\user\Desktop\R&S 
>> %20CCIE\Recommended%20Reading\Books\Cisco%20press\Jeff%20Doyle 
>> \CCIE_Professional_Development_Routing_TCPIP, 
>> _Volume_I,_Second_Edition.chm::/1587052024/ 
>> ch08lev1sec1.html#ch08tn01>
>>
>> No
>>
>> No
>>
>> No
>>
>> Not-so-stubby
>>
>> Yes
>>
>> Yes
>>
>> Yes
>>
>> No
>>
>> Yes
>>
>> [*] Except for a single type 3 LSA per ABR, advertising the default  
>> route
>>
>>
>>
>> Regards,
>>
>> Molomo
>>
>>
>> Blogs and organic groups at http://www.ccie.net
>>
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>>
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>>
>>
>>
>>
>>
>>
>>
>>
>>
>> -- 
>> Narbik Kocharians
>> CCSI#30832, CCIE# 12410 (R&S, SP, Security)
>> www.MicronicsTraining.com
>> Sr. Technical Instructor
>
>
>
> -- 
> Narbik Kocharians
> CCSI#30832, CCIE# 12410 (R&S, SP, Security)
> www.MicronicsTraining.com
> Sr. Technical Instructor
Blogs and organic groups at http://www.ccie.net
Received on Sun Sep 06 2009 - 20:44:03 ART

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