Re: OSPF SHAM-LINK

Are you sure your sham-link is actually working? It doesn't sound like it
is. If the sham-link was up you would have intra-area O routes here. Take
a look at "sh ip ospf neighbor". Do you see an adjacency over the
sham-link?

On Tue, Mar 30, 2010 at 3:46 AM, Joe Astorino <jastorino_at_ipexpert.com>wrote:

> Post your configurations
>
>
> On Tue, Mar 30, 2010 at 2:43 AM, Abiola Jewoola <biola_y2k_at_yahoo.com>wrote:
>
>> I had already increased the cost of the back door link very high.
>>
>> Still the ospf is preferring to go through the back door link
>>
>>
>> --- On *Mon, 3/29/10, Joe Astorino <jastorino_at_ipexpert.com>* wrote:
>>
>>
>> From: Joe Astorino <jastorino_at_ipexpert.com>
>>
>> Subject: Re: OSPF SHAM-LINK
>> To: "Abiola Jewoola" <biola_y2k_at_yahoo.com>
>> Cc: "Ahmed Ejaz" <aahmedejaz_at_gmail.com>, ccielab_at_groupstudy.com
>> Date: Monday, March 29, 2010, 11:10 PM
>>
>> Ahhh...yes well then that is a different story. Typically we see both
>> remote sites configured for area 0. In your case if both the backdoor
>> link
>> and the sham-link learned routes are O IA all you should need to do is
>> tweak
>> the OSPF metric by manipulating cost where necessary. Just remember that
>> cost is calculated by adding in the cost of your inbound link.
>>
>> On Tue, Mar 30, 2010 at 1:39 AM, Abiola Jewoola <biola_y2k@yahoo.com<http://mc/compose?to=biola_y2k@yahoo.com>>
>> wrote:
>>
>> >
>> >
>> > Find attached the configs on my PE routers.
>> >
>> > The process id is the same and i also include the same domain-id . but
>> the
>> > routes still comes as IA. i guess because the PE routers area pairing
>> with
>> > CE routers with different areas.
>> >
>> >
>> >
>> > --- On *Mon, 3/29/10, Ahmed Ejaz <aahmedejaz@gmail.com<http://mc/compose?to=aahmedejaz@gmail.com>>*
>> wrote:
>> >
>> >
>> > From: Ahmed Ejaz <aahmedejaz@gmail.com<http://mc/compose?to=aahmedejaz@gmail.com>
>> >
>> > Subject: Re: OSPF SHAM-LINK
>> > To: "Joe Astorino" <jastorino@ipexpert.com<http://mc/compose?to=jastorino@ipexpert.com>
>> >
>> > Cc: "Abiola Jewoola" <biola_y2k@yahoo.com<http://mc/compose?to=biola_y2k@yahoo.com>>,
>> ccielab@groupstudy.com <http://mc/compose?to=ccielab@groupstudy.com>
>> > Date: Monday, March 29, 2010, 9:57 PM
>> >
>> >
>> > I guess the ospf process which you are redistributing into bgp requires
>> a
>> > domain id, that is the reason it is treating it as an IA route. Please
>> add a
>> > domain id on both the sides and the routes should come up as O routes
>> then
>> > you can modify the cost to not prefer the sham link.
>> >
>> > HTH
>> > Ahmed
>> >
>> > On Tue, Mar 30, 2010 at 7:43 AM, Joe Astorino <jastorino@ipexpert.com<http://mc/compose?to=jastorino@ipexpert.com>
>> <http://mc/compose?to=jastorino@ipexpert.com>
>>
>> > > wrote:
>> >
>> >> OSPF routes coming over the sham-link should be regular O routes
>> >> (intra-area) and thus should be preferred over O IA routes...post your
>> >> configurations something does not seem right about that.
>> >>
>> >>
>> >>
>> >> On Mon, Mar 29, 2010 at 10:35 PM, Abiola Jewoola <biola_y2k@yahoo.com<http://mc/compose?to=biola_y2k@yahoo.com>
>> <http://mc/compose?to=biola_y2k@yahoo.com>>
>>
>> >> wrote:
>> >> > Hello G.S
>> >> >
>> >> > How can i make ospf prefer to forward route routes via ospf
>> sham-link.
>> >> The
>> >> > sham link has has a cost of 10 and the routes are coming as IA routes
>> >> across
>> >> > the MPLS backbone
>> >> >
>> >> > The router is preferring the backdoor link even when i have increased
>> >> the cost
>> >> > as high as 65000. The routes are also advertised as IA routes.
>> >> >
>> >> > Regards,
>> >> > Abiola
>> >> >
>> >> >
>> >> > Blogs and organic groups at http://www.ccie.net
>> >> >
>> >> >
>> _______________________________________________________________________
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>> >> >
>> >> >
>> >> >
>> >> >
>> >> >
>> >> >
>> >>
>> >>
>> >>
>> >> --
>> >> Regards,
>> >>
>> >>
>> >>
>> >> Joe Astorino - CCIE #24347
>> >> Sr. Technical Instructor - IPexpert
>> >> Mailto: jastorino@ipexpert.com<http://mc/compose?to=jastorino@ipexpert.com>
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>> --
>> Regards,
>>
>>
>>
>> Joe Astorino - CCIE #24347
>> Sr. Technical Instructor - IPexpert
>> Mailto: jastorino@ipexpert.com<http://mc/compose?to=jastorino@ipexpert.com>
>> Telephone: +1.810.326.1444
>> Live Assistance, Please visit: www.ipexpert.com/chat
>> eFax: +1.810.454.0130
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>> IPexpert is a premier provider of Self-Study Workbooks, Video on Demand,
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>> CCIE (R&S, Voice, Security & Service Provider) certification(s) with
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>> _______________________________________________________________________
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>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
> --
> Regards,
>
>
>
> Joe Astorino - CCIE #24347
> Sr. Technical Instructor - IPexpert
> Mailto: jastorino_at_ipexpert.com
> Telephone: +1.810.326.1444
> Live Assistance, Please visit: www.ipexpert.com/chat
> eFax: +1.810.454.0130
>
> IPexpert is a premier provider of Self-Study Workbooks, Video on Demand,
> Audio Tools, Online Hardware Rental and Classroom Training for the Cisco
> CCIE (R&S, Voice, Security & Service Provider) certification(s) with
> training locations throughout the United States, Europe, South Asia and
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-- 
Regards,
Joe Astorino - CCIE #24347
Sr. Technical Instructor - IPexpert
Mailto: jastorino_at_ipexpert.com
Telephone: +1.810.326.1444
Live Assistance, Please visit: www.ipexpert.com/chat
eFax: +1.810.454.0130
IPexpert is a premier provider of Self-Study Workbooks, Video on Demand,
Audio Tools, Online Hardware Rental and Classroom Training for the Cisco
CCIE (R&S, Voice, Security & Service Provider) certification(s) with
training locations throughout the United States, Europe, South Asia and
Australia. Be sure to visit our online communities at
www.ipexpert.com/communities and our public website at www.ipexpert.com
Blogs and organic groups at http://www.ccie.net