Re: preferring OSPF inter-area compared to intra-area

Guys, I don't want to be between the devil and the deep blue sea but:
I'm a INE customer and I did write that in a previous mail. If a INE
competitor wants to spend his time and help me I'm more than happy. I do
also think that trainers are not here only for having an implicit
advertisement of their company.
Said so I was actually happy with both answers.. route-map thing triggered
from my 1st question (the one in the subjetc).
Narbik has is own way to prove result, creating specific practice labs,
maybe Brian likes going to the point with theory (documentation and rfc).
This is a free mailing list.. I don't pay anything for it and I appreciated
everyone takes his time reading my email and helping me in understanding
where I'm wrong.
Then.. I will lab what Narbik suggested and see if it matches with what
Brian wrote. (one is saying the opposite of the other, so it should be easy
to find who is wrong)
Then.. I'm a happy INE customer and I heard every day very nice feedback
from Narbik's customers.. You guys are the best in the market and this
mailing list should be kept free from personal non-technical
debates/discussions.
Thanks for your time Brian and Narbik (and Pete and Carlos).. I will lab
this asap and get back here if something it's still not clear.

On Tue, Jan 8, 2013 at 7:07 AM, Narbik Kocharians <narbikk_at_gmail.com> wrote:

> Let me enlighten you. Read ccie99999's post, his last one.
>
> Who ever is reading this post, please let me know if I was out of hand and
> i was spamming. Don't unicast, send it to all. so you can enlighten this
> gentleman.
>
>
> On Mon, Jan 7, 2013 at 11:02 PM, Brian McGahan <bmcgahan_at_ine.com> wrote:
>
>> The subject title is preferring OSPF inter-area compared to
>> intra-area. Please enlighten us as to how your input tells us how to
>> prefer OSPF Inter-Area routes over Intra-Area routes.****
>>
>> ** **
>>
>> Brian McGahan, CCIE #8593 (R&S/SP/Security)****
>>
>> bmcgahan_at_INE.com****
>>
>> ** **
>>
>> Internetwork Expert, Inc.****
>>
>> http://www.INE.com****
>>
>> ** **
>>
>> *From:* Narbik Kocharians [mailto:narbikk_at_gmail.com]
>> *Sent:* Tuesday, January 08, 2013 12:41 AM
>> *To:* Brian McGahan
>> *Cc:* ccie99999; Carlos G Mendioroz; Cisco certification
>>
>> *Subject:* Re: preferring OSPF inter-area compared to intra-area****
>>
>> ** **
>>
>> WOW....****
>>
>> First of all what I wrote is very applicable to the question that
>> ccie99999 had in this post. Because he was complaining that it does not
>> work. The following is his post:****
>>
>> "*What I was complaining is that route-map matching ip next-hop or
>> matching**
>> ip route-source is not working when applied with a distribute list inbound
>> to ospf.
>> Strange I don't find any official reference on this scenario.*"
>> Did i miss something?****
>>
>> ** **
>>
>> What are you referring to? Please be more specific. ****
>>
>> These are NOT labs from my book, people that have my books will tell you
>> that these labs are NOT from my book. I just took my time to respond with
>> the configuration that clearly shows that the options work correctly.
>> Besides even if I post something from my book, so what? Are you the
>> moderator? Why don't we get Paul B involved, because you are totally our
of
>> hand. ****
>>
>> ** **
>>
>> BTW, you agreed that these options do not work, or they are not
>> supported, and the above configuration proves that you are wrong. AGAIN.*
>> ***
>>
>> ** **
>>
>> ** **
>>
>> On Mon, Jan 7, 2013 at 10:30 PM, Brian McGahan <bmcgahan_at_ine.com> wrote:*
>> ***
>>
>> Hi Narbik,****
>>
>> ****
>>
>> I would argue that your response is spam, and is not
>> applicable to the list. Once again you are posting out of context free
>> lab material without answering the original posters question. I could
>> likewise post output from INEs lab workbooks or from Ciscos
documentation
>> but that is not productive. If you have technology discussion input to
>> give we are more than happy to accept it.****
>>
>> ****
>>
>> Thanks,****
>>
>> ****
>>
>> Brian McGahan, CCIE #8593 (R&S/SP/Security)****
>>
>> bmcgahan_at_INE.com****
>>
>> ****
>>
>> Internetwork Expert, Inc.****
>>
>> http://www.INE.com****
>>
>> ****
>>
>> *From:* Narbik Kocharians [mailto:narbikk_at_gmail.com]
>> *Sent:* Monday, January 07, 2013 11:15 PM
>> *To:* ccie99999
>> *Cc:* Brian McGahan; Carlos G Mendioroz; Cisco certification****
>>
>>
>> *Subject:* Re: preferring OSPF inter-area compared to intra-area****
>>
>> ****
>>
>> *SORRY FOR THE LONG POST.*****
>>
>> ****
>>
>> *Lets say we have a hub and spoke topology, where R1 is the hub router,
>> and R2, R3, and R4 are the spoke routers. All the links are configured as
>> P2P using the following IP addressing scheme:*****
>>
>> ****
>>
>>
R1(S0/0.12)12.1.1.1/24--------------12.1.1.2(S0/0.21)R2<http://12.1.1.1/24---
-----------12.1.1.2%28S0/0.21%29R2>
>> ****
>>
>>
R1(S0/0.13)13.1.1.1/24--------------13.1.1.3(S0/0.31)R3<http://13.1.1.1/24---
-----------13.1.1.3%28S0/0.31%29R3>
>> ****
>>
>>
R1(S0/0.14)14.1.1.1/24--------------14.1.1.4(S0/0.41)R4<http://14.1.1.1/24---
-----------14.1.1.4%28S0/0.41%29R4>
>> ****
>>
>> ****
>>
>> *R2 is running OSPF on its Lo0 and Lo1 with IP addresses of 2.2.2.2/8and
>> 200.2.2.2/24 respectively.*****
>>
>> * *****
>>
>> *R3 is running ospf on its Lo0 with an IP address of 3.3.3.3/8*****
>>
>> *R4 is running ospf on its Lo0 with an IP address of 4.4.4.4/8*****
>>
>> * *****
>>
>> *Everything is running in OSPF area 0. Lets begin:*****
>>
>> ****
>>
>> *On R1*****
>>
>> ****
>>
>> R1#Show ip route ospf | I O****
>>
>> *O 2.0.0.0/8 [110/65] via 12.1.1.2, 00:01:24, Serial0/0.12*****
>>
>> O 3.0.0.0/8 [110/65] via 13.1.1.3, 00:00:44, Serial0/0.13****
>>
>> O 4.0.0.0/8 [110/65] via 14.1.1.4, 00:00:14, Serial0/0.14****
>>
>> *O 200.2.2.0/24 [110/65] via 12.1.1.2, 00:01:24, Serial0/0.12*****
>>
>> ****
>>
>> *You can see that R1 is receiving two routes from R2, networks
2.0.0.0/8and
>> 200.2.2.0/24.*****
>>
>> ****
>>
>> *Lets filter all routes coming through S0/0.12:*****
>>
>> ****
>>
>> *On R1*****
>>
>> ****
>>
>> R1(config)#*Route-map tst deny 10*****
>>
>> R1(config-route-map)#*match interface s0/0.12*****
>>
>> R1(config)#*route-map tst permit 90*****
>>
>> ****
>>
>> R1(config-route-map)#*router ospf 1*****
>>
>> R1(config-router)#*distribute-list route-map tst in*****
>>
>> ****
>>
>> R1#*Show ip route ospf | I O*****
>>
>> O 3.0.0.0/8 [110/65] via 13.1.1.3, 00:00:38, Serial0/0.13****
>>
>> O 4.0.0.0/8 [110/65] via 14.1.1.4, 00:00:38, Serial0/0.14****
>>
>> ****
>>
>> *Lets remove the previous solution and filter network 2.0.0.0/8 coming
>> through S0/0.21 sub-interface:*****
>>
>> ****
>>
>> R1(config)#*No route-map tst*****
>>
>> ****
>>
>> R1(config)#*router ospf 1*****
>>
>> R1(config-router)#*No distribute-list route-map tst in*****
>>
>> ****
>>
>> R1#*Show ip route ospf | I O*****
>>
>> O 2.0.0.0/8 [110/65] via 12.1.1.2, 00:00:19, Serial0/0.12****
>>
>> O 3.0.0.0/8 [110/65] via 13.1.1.3, 00:00:19, Serial0/0.13****
>>
>> O 4.0.0.0/8 [110/65] via 14.1.1.4, 00:00:19, Serial0/0.14****
>>
>> O 200.2.2.0/24 [110/65] via 12.1.1.2, 00:00:19, Serial0/0.12****
>>
>> ****
>>
>> *The previous solution will NOT work here; to filter network
2.0.0.0/8coming through S0/0.21 we need to do the following:
>> *****
>>
>> ****
>>
>> R1(config)#*access-list 2 permit 2.0.0.0 0.255.255.255*****
>>
>> ****
>>
>> R1(config)#*route-map tst deny 10*****
>>
>> R1(config-route-map)#*match interface s0/0.12*****
>>
>> R1(config-route-map)#*match ip addr 2*****
>>
>> R1(config)#*route-map tst permit 90*****
>>
>> ****
>>
>> R1(config-route-map)#*router ospf 1*****
>>
>> R1(config-router)#*distribute-list route-map tst in*****
>>
>> ****
>>
>> R1#*Show ip route ospf | I O*****
>>
>> O 3.0.0.0/8 [110/65] via 13.1.1.3, 00:00:23, Serial0/0.13****
>>
>> O 4.0.0.0/8 [110/65] via 14.1.1.4, 00:00:23, Serial0/0.14****
>>
>> O 200.2.2.0/24 [110/65] via 12.1.1.2, 00:00:23, Serial0/0.12****
>>
>> ****
>>
>> *Perfect it worked, obviously the same task can be configured using
>> another method.*****
>>
>> * *****
>>
>> *Lets remove the configuration from the previous solution and filter
>> network 200.2.2.0/24 coming from R2, but this time we are going to use
>> the IP Next-hop option:*****
>>
>> ****
>>
>> R1(config)#*No route-map tst*****
>>
>> R1(config)#*No access-list 2*****
>>
>> ****
>>
>> R1(config)#*router ospf 1*****
>>
>> R1(config-router)#*No distribute-list route-map tst in*****
>>
>> ****
>>
>> R1#*Show ip route ospf | I O*****
>>
>> O 2.0.0.0/8 [110/65] via 12.1.1.2, 00:00:29, Serial0/0.12****
>>
>> O 3.0.0.0/8 [110/65] via 13.1.1.3, 00:00:29, Serial0/0.13****
>>
>> O 4.0.0.0/8 [110/65] via 14.1.1.4, 00:00:29, Serial0/0.14****
>>
>> O 200.2.2.0/24 [110/65] via 12.1.1.2, 00:00:29, Serial0/0.12****
>>
>> ****
>>
>> *To filter using the IP next-hop option:*****
>>
>> ****
>>
>> ****
>>
>> R1(config)#*access-list 1 permit 200.2.2.0 0.0.0.255*****
>>
>> ****
>>
>> R1(config)#*access-list 10 permit host 12.1.1.2*****
>>
>> ****
>>
>> R1(config)#*route-map tst deny 10*****
>>
>> R1(config-route-map)#*match ip addr 1*****
>>
>> R1(config-route-map)#*match ip next-hop 10*****
>>
>> R1(config)#*route-map tst permit 90*****
>>
>> ****
>>
>> R1(config-route-map)#*router ospf 1*****
>>
>> R1(config-router)#*distribute-list route-map tst in*****
>>
>> ****
>>
>> R1#*Show ip route ospf | I O*****
>>
>> O 2.0.0.0/8 [110/65] via 12.1.1.2, 00:00:05, Serial0/0.12****
>>
>> O 3.0.0.0/8 [110/65] via 13.1.1.3, 00:00:05, Serial0/0.13****
>>
>> O 4.0.0.0/8 [110/65] via 14.1.1.4, 00:00:05, Serial0/0.14****
>>
>> * *****
>>
>> *Now.lets remove the previous solution and use the route-source
>> option:*****
>>
>> ****
>>
>> R1(config)#*No access-list 1* ****
>>
>> R1(config)#*No access-list 10* ****
>>
>> R1(config)#*No route-map tst*****
>>
>> R1(config)#*router ospf 1*****
>>
>> R1(config-router)#*No distribute-list route-map tst in*****
>>
>> ****
>>
>> R1#*Show ip route ospf | I O*****
>>
>> O 2.0.0.0/8 [110/65] via 12.1.1.2, 00:00:34, Serial0/0.12****
>>
>> O 3.0.0.0/8 [110/65] via 13.1.1.3, 00:00:34, Serial0/0.13****
>>
>> O 4.0.0.0/8 [110/65] via 14.1.1.4, 00:00:34, Serial0/0.14****
>>
>> O 200.2.2.0/24 [110/65] via 12.1.1.2, 00:00:34, Serial0/0.12****
>>
>> ****
>>
>> * *****
>>
>> *To use the route-source option, we MUST use the RID of R2 in the
>> access-list. To find out the RID of R2:*****
>>
>> ****
>>
>> R2#*Show ip ospf | I ID*****
>>
>> *Routing Process "ospf 1" with ID 0.0.0.2*****
>>
>> ****
>>
>> R1(config)#*access-list 3 permit 0.0.0.2*****
>>
>> R1(config)#*access-list 30 permit 200.2.2.0 0.0.0.255*****
>>
>> ****
>>
>> R1(config)#*route-map tst deny 10*****
>>
>> R1(config-route-map)#*match ip addr 30*****
>>
>> R1(config-route-map)#*match ip route-source 3*****
>>
>> R1(config)#*route-map tst permit 90*****
>>
>> R1(config-route-map)#*router ospf 1*****
>>
>> R1(config-router)#*distribute-list route-map tst in*****
>>
>> ****
>>
>> R1#*Show ip route ospf | I O*****
>>
>> O 2.0.0.0/8 [110/65] via 12.1.1.2, 00:00:06, Serial0/0.12****
>>
>> O 3.0.0.0/8 [110/65] via 13.1.1.3, 00:00:06, Serial0/0.13****
>>
>> O 4.0.0.0/8 [110/65] via 14.1.1.4, 00:00:06, Serial0/0.14****
>>
>> ****
>>
>> ****
>>
>> I hope this helped. ****
>>
>> ****
>>
>> On Mon, Jan 7, 2013 at 7:09 PM, ccie99999 <ccie99999_at_gmail.com> wrote:***
>> *
>>
>> Thanks for your reply Brian..
>>
>> I see your point about filtering the RIB and not what OSPF chooses. ( I
>> didn't realize this before actually)
>>
>> What I was complaining is that route-map matching ip next-hop or matching
>> ip route-source is not working when applied with a distribute list inbound
>> to ospf.
>> Strange I don't find any official reference on this scenario.****
>>
>>
>>
>> On Mon, Jan 7, 2013 at 6:08 PM, Brian McGahan <bmcgahan_at_ine.com> wrote:
>>
>> > This filters the RIB (routing table), not the OSPF decision process. By
>> > the time you apply this OSPF has already chosen the intra area route
>> over
>> > the inter area one, so all you can do is permit or deny the intra area
>> one.
>> >
>> > The only way to really accomplish this is to make the two route types
>> > equal. If you were to change the inter area route to intra area with
>> > something like a virtual link or tunnel then you can modify which path
>> is
>> > preferred.
>> >
>>
>> ****
>>
>> --
>> @ccie99999****
>>
>>
>>
>> Blogs and organic groups at http://www.ccie.net
>>
>> _______________________________________________________________________
>> Subscription information may be found at:
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>>
>>
>>
>>
>>
>> ****
>>
>>
>>
>> ****
>>
>> ****
>>
>> -- ****
>>
>> *Narbik Kocharians**
>> *CCSI#30832, CCIE# 12410 (R&S, SP, Security)
>> *www.MicronicsTraining.com* <http://www.micronicstraining.com/>
>> Sr. Technical Instructor ****
>>
>> YES! We take Cisco Learning Credits!
>> A Cisco Learning Partner****
>>
>>
>>
>> ****
>>
>> ** **
>>
>> -- ****
>>
>> *Narbik Kocharians**
>> *CCSI#30832, CCIE# 12410 (R&S, SP, Security)
>> *www.MicronicsTraining.com* <http://www.micronicstraining.com/>
>> Sr. Technical Instructor ****
>>
>> YES! We take Cisco Learning Credits!
>> A Cisco Learning Partner****
>>
>
>
>
> --
> *Narbik Kocharians
> *CCSI#30832, CCIE# 12410 (R&S, SP, Security)
> *www.MicronicsTraining.com* <http://www.micronicstraining.com/>
> Sr. Technical Instructor
> YES! We take Cisco Learning Credits!
> A Cisco Learning Partner
>

--
@ccie99999
Blogs and organic groups at http://www.ccie.net