Re: OSPF SHAM-LINK

Make both CE sites the same OSPF area

On Tue, Mar 30, 2010 at 5:44 AM, Abiola Jewoola <biola_y2k_at_yahoo.com> wrote:

>
> Yea,
>
> My sham is link up from both sides from the show ip ospf sham-link output
> a
>
> And full from the show ip ospf nei output!
>
>
>
>
> --- On *Tue, 3/30/10, 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: Tuesday, March 30, 2010, 2:38 AM
>
>
> 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@ipexpert.com<http://mc/compose?to=jastorino@ipexpert.com>
> > wrote:
>
>> Post your configurations
>>
>>
>> On Tue, Mar 30, 2010 at 2:43 AM, Abiola Jewoola <biola_y2k@yahoo.com<http://mc/compose?to=biola_y2k@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@ipexpert.com<http://mc/compose?to=jastorino@ipexpert.com>
>>> >* wrote:
>>>
>>>
>>> From: Joe Astorino <jastorino@ipexpert.com<http://mc/compose?to=jastorino@ipexpert.com>
>>> >
>>>
>>> Subject: Re: OSPF SHAM-LINK
>>> To: "Abiola Jewoola" <biola_y2k@yahoo.com<http://mc/compose?to=biola_y2k@yahoo.com>
>>> >
>>> Cc: "Ahmed Ejaz" <aahmedejaz@gmail.com<http://mc/compose?to=aahmedejaz@gmail.com>>,
>>> ccielab@groupstudy.com <http://mc/compose?to=ccielab@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
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>>>
>>>
>>> Joe Astorino - CCIE #24347
>>> Sr. Technical Instructor - IPexpert
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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
>>
>> 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
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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
>
> 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
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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