Re: split horizon

Ah, I see. Yeah that will work as well.

On Tue, Jan 5, 2010 at 3:17 PM, swap m <ccie19804_at_gmail.com> wrote:

> Bryan,
>
> it can look something like this.
>
> on Hub,
> 1. add a static 1.1.1.0/23 to null0
> 2. redis this into OSPF on hub
> 3. this will reach spoke1 via Hub-PE-CE ospf and then MPBGP and then
> Spoke1-PE-CE OSPF.... Spoke2 can be specially filtered as it doesnt need
> this blackhole route.
>
> Swap
> #19084
>
> On Wed, Jan 6, 2010 at 1:58 AM, Bryan Bartik <bbartik_at_ipexpert.com> wrote:
>
>> Mirco,
>>
>> I have not seen that example before. Can you post an example of the Hub CE
>> config?
>>
>> On Tue, Jan 5, 2010 at 2:51 PM, Mirco Orlandi <mirco.orlandi_at_gmail.com
>> >wrote:
>>
>> > Bryan,
>> > double link solution work well, without additional prefix advertising.
>> >
>> > ...but still work with a single link and additional blackhole route
>> > advertising at hub ce. Then we can mantain control of spoke2spoke
>> traffic
>> > with acl on hub ce wan interface.
>> >
>> > In double link scenario we have two link used in unidirectional way for
>> > spoke2spoke traffic; in single link scenario, one link used in
>> bidirectional
>> > way.
>> > I think this is more common hub&spoke scenario. Do you agree?
>> >
>> > Regards,
>> > mirco.
>> >
>> >
>> > On Tue, Jan 5, 2010 at 9:17 PM, Bryan Bartik <bbartik_at_ipexpert.com>
>> wrote:
>> >
>> >> Hub and Spoke VPNs usually require two links between the hub CE and PE.
>> >> Each
>> >> link is in a separate VRF on the PE side. The first VRF imports all the
>> >> spoke routes and advertise them to the hub CE. The second VRF will take
>> >> these routes from the CE and advertise them back to the spokes with a
>> >> different RT. The spoke sites will then import this second RT (not the
>> >> first). This pulls all traffic from the spokes to the Hub CE and back
>> out.
>> >>
>> >> Remember the goal is to not only get traffic to the Hub PE, but the Hub
>> >> CE...which is the tricky part. It has nothing to do with split horizon,
>> >> but
>> >> rather the way a router builds the shortest path tree. A shortest path
>> >> will
>> >> never include the same link in two directions without some funky
>> >> engineering.
>> >>
>> >> If you have only have one link between PE and CE, I believe this is not
>> a
>> >> true hub and spoke and the problem is you are not importing the spoke
>> RTs
>> >> and at each of the other spokes, only the hub.
>> >>
>> >> On Tue, Jan 5, 2010 at 1:01 PM, <olukolade_at_gmail.com> wrote:
>> >>
>> >> > Ignore pls. Been drinking.
>> >> > Sent from my BlackBerry. wireless handheld from Glo Mobile.
>> >> >
>> >> > -----Original Message-----
>> >> > From: olukolade_at_gmail.com
>> >> > Date: Tue, 5 Jan 2010 19:23:35
>> >> > To: jack daniels<jckdaniels12_at_gmail.com>; <
>> Charles.Henson_at_regions.com>
>> >> > Cc: Cisco certification<ccielab_at_groupstudy.com>; Marko Milivojevic<
>> >> > markom_at_ipexpert.com>; <nobody_at_groupstudy.com>
>> >> > Subject: Re: split horizon
>> >> >
>> >> > Hi jack,
>> >> > CE hub won't be doing the advertisement. It will be done by PE1.
>> Don't
>> >> > forget PE1 is also running ospf and has all the routes in bgp. So
>> routes
>> >> > from the other PEs will be tagged with RT 2:2 and exported. This will
>> be
>> >> > imported on the other PEs where the routes from PE2 will be imported
>> by
>> >> PE3
>> >> > and vice versa. These routes are then redistributed into ospf for the
>> >> > connected CEs. The CEs will not advertise the routes learnt from the
>> PE
>> >> back
>> >> > to them and there will be no need to do this.
>> >> >
>> >> > Kolade
>> >> > Sent from my BlackBerry. wireless handheld from Glo Mobile.
>> >> >
>> >> > -----Original Message-----
>> >> > From: jack daniels <jckdaniels12_at_gmail.com>
>> >> > Date: Wed, 6 Jan 2010 00:06:14
>> >> > To: <Charles.Henson_at_regions.com>
>> >> > Cc: Cisco certification<ccielab_at_groupstudy.com>; Marko Milivojevic<
>> >> > markom_at_ipexpert.com>; <nobody_at_groupstudy.com>
>> >> > Subject: Re: split horizon
>> >> >
>> >> > CE (HUB)
>> >> > G0/1
>> >> > |
>> >> > OSPF
>> >> > |
>> >> > PE1
>> >> > |
>> >> > MPLS CLOUD-----------------------------PE2------OSPF-CE(SPOKE1)
>> (
>> >> > 2.2.2.0/24)
>> >> >
>> >> > |
>> >> > |
>> >> > |
>> >> > PE3
>> >> > |
>> >> > OSPF
>> >> > |
>> >> > CE(SPOKE2) (1.1.1.0/24)
>> >> >
>> >> > IN VRF of customer -
>> >> >
>> >> > PE3 advertises 1.1.1.0/24 routes with RT1:1 and imports 2:2
>> >> >
>> >> > PE2 advertises 2.2.2.0/24 routes with RT 1:1 and imports 2:2
>> >> >
>> >> > PE1 exports routes with RT 2:2 and imports 1:1
>> >> >
>> >> >
>> >> >
>> >> > NOW 1.1.1.0/24 is learnt on CE HUB Gi0/1 via OSPF .....
>> >> > Will CE HUB advertise 1.1.1.0/24 on Gi0/1 back as it is required
>> for
>> >> CE
>> >> > SPOKE1 for SPOKE to SPOKE reachabilty via HUB?
>> >> >
>> >> >
>> >> > On Tue, Jan 5, 2010 at 11:57 PM, <Charles.Henson_at_regions.com> wrote:
>> >> >
>> >> > > Hey Jack,
>> >> > > How about a little more details? Configs? Shows? Anything?
>> Marko
>> >> is
>> >> > > correct.
>> >> > >
>> >> > > Charles Henson
>> >> > >
>> >> > >
>> >> > >
>> >> > >
>> >> > >
>> >> > > |------------>
>> >> > > | From: |
>> >> > > |------------>
>> >> > >
>> >> > >
>> >> >
>> >>
>> >--------------------------------------------------------------------------------------------------------------------------------------------------|
>> >> > > |jack daniels <jckdaniels12_at_gmail.com>
>> >> > >
>> >> > |
>> >> > >
>> >> > >
>> >> >
>> >>
>> >--------------------------------------------------------------------------------------------------------------------------------------------------|
>> >> > > |------------>
>> >> > > | To: |
>> >> > > |------------>
>> >> > >
>> >> > >
>> >> >
>> >>
>> >--------------------------------------------------------------------------------------------------------------------------------------------------|
>> >> > > |Marko Milivojevic <markom_at_ipexpert.com>
>> >> > >
>> >> > |
>> >> > >
>> >> > >
>> >> >
>> >>
>> >--------------------------------------------------------------------------------------------------------------------------------------------------|
>> >> > > |------------>
>> >> > > | Cc: |
>> >> > > |------------>
>> >> > >
>> >> > >
>> >> >
>> >>
>> >--------------------------------------------------------------------------------------------------------------------------------------------------|
>> >> > > |Cisco certification <ccielab_at_groupstudy.com>
>> >> > >
>> >> > |
>> >> > >
>> >> > >
>> >> >
>> >>
>> >--------------------------------------------------------------------------------------------------------------------------------------------------|
>> >> > > |------------>
>> >> > > | Date: |
>> >> > > |------------>
>> >> > >
>> >> > >
>> >> >
>> >>
>> >--------------------------------------------------------------------------------------------------------------------------------------------------|
>> >> > > |01/05/2010 12:21 PM
>> >> > >
>> >> |
>> >> > >
>> >> > >
>> >> >
>> >>
>> >--------------------------------------------------------------------------------------------------------------------------------------------------|
>> >> > > |------------>
>> >> > > | Subject: |
>> >> > > |------------>
>> >> > >
>> >> > >
>> >> >
>> >>
>> >--------------------------------------------------------------------------------------------------------------------------------------------------|
>> >> > > |Re: split horizon
>> >> > >
>> >> |
>> >> > >
>> >> > >
>> >> >
>> >>
>> >--------------------------------------------------------------------------------------------------------------------------------------------------|
>> >> > >
>> >> > >
>> >> > >
>> >> > >
>> >> > >
>> >> > > I understand that but ,u mean in OSPF
>> >> > >
>> >> > > IF i recive 1.1.1.0/24 on G0/1 of HUB
>> >> > >
>> >> > > I'LL advertise 1.1.1.0/24 on Gi0/1 (SAME INTERFACE) of HUB
>> >> > >
>> >> > >
>> >> > >
>> >> > >
>> >> > > On Tue, Jan 5, 2010 at 11:44 PM, Marko Milivojevic
>> >> > > <markom_at_ipexpert.com>wrote:
>> >> > >
>> >> > > > On Tue, Jan 5, 2010 at 19:00, jack daniels <
>> jckdaniels12_at_gmail.com
>> >> >
>> >> > > > wrote:
>> >> > > > > Hi guys,
>> >> > > > >
>> >> > > > > I have a scenario where in MPLS VPN - HUB and SPOKE.
>> >> > > > >
>> >> > > > > CE-PE protocol is OSPF everywhere
>> >> > > > >
>> >> > > > >
>> >> > > > > HUB is recieving routes from one SPOKE on int G0/1 and not
>> >> > advertiseing
>> >> > > > on
>> >> > > > > same (SPLIT horizon).
>> >> > > > >
>> >> > > > > In ospf how can we overcome such issue.
>> >> > > >
>> >> > > > OSPF is a link state protocol. It doesn't use split horizon (at
>> >> least
>> >> > > > not within the same area and even in multiarea, the behavior is
>> not
>> >> > > > called that). You are probably having some other issue...
>> >> > > >
>> >> > > > --
>> >> > > > Marko Milivojevic - CCIE #18427
>> >> > > > Senior Technical Instructor - IPexpert
>> >> > > >
>> >> > > > Mailto: markom_at_ipexpert.com
>> >> > > > Telephone: +1.810.326.1444
>> >> > > > Fax: +1.810.454.0130
>> >> > > > Community: http://www.ipexpert.com/communities
>> >> > >
>> >> > >
>> >> > > Blogs and organic groups at http://www.ccie.net
>> >> > >
>> >> > >
>> >> _______________________________________________________________________
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>> >> >
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>> >> >
>> >> >
>> >> >
>> >> >
>> >> >
>> >> >
>> >> >
>> >>
>> >>
>> >> --
>> >> Bryan Bartik
>> >> CCIE #23707 (R&S, SP), CCNP
>> >> Sr. Support Engineer - IPexpert, Inc.
>> >> URL: http://www.IPexpert.com
>> >>
>> >>
>> >> Blogs and organic groups at http://www.ccie.net
>> >>
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>> >>
>> >>
>> >>
>> >>
>> >>
>> >>
>> >
>>
>>
>> --
>> Bryan Bartik
>> CCIE #23707 (R&S, SP), CCNP
>> Sr. Support Engineer - IPexpert, Inc.
>> URL: http://www.IPexpert.com
>>
>>
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>>
>>
>

-- 
Bryan Bartik
CCIE #23707 (R&S, SP), CCNP
Sr. Support Engineer - IPexpert, Inc.
URL: http://www.IPexpert.com
Blogs and organic groups at http://www.ccie.net