The MPLS-OPS Archive

[Spice Sylvia <falsesylvia@yahoo.co.uk>]

Pardon me if I am not clear,

 

Why would RD have changed?

 

Same IP route to same prefix but why different RD?

 

Why would one not give both to same vrf1 in hub and spoke?

Aamer Akhter <aakhter@cisco.com> wrote:

On 5/14/03 1:58 PM, "Spice Sylvia" wrote:

> Hello Aamer,
>
> Why would the "rd" have changed?

|--------1
HUBCE HUBPE
|--------2

Suppose the sites prefixes are sent to the HUBPE, which advertises to HUBCE
over link 2 (lets' call this vrf2), the HUBCE advertises this back to the
HUBPE over link 1 (vrf1). vrf2 and vrf1 will have different rd's because
they are different vrfs.

>
> Is this a new feature?
>
> How does changing RD help?
>
>
> Aamer Akhter wrote:
> On 5/14/03 10:51 AM, "Ferit Yegenoglu" wrote:
>
>>
>> Sylvia,
>>
>> One possible scenario where this could happen is the hub-spoke BGP/MPLS
>> VPN. In this case the spoke PEs advertise their routes with a Route
>> Target val! ue "Hub". The hub PE imports these routes and advertises them
>> to the CE router in the hub site. These routes are advertised across the
>> hub site and eventually back to the PE hub router via a different
>> interface. The PE hub router then readvertises these routes to the spoke
>> PEs with a Route Target value "Spoke" and a different VPN label.
>
> But to BGP, these "readvertised" prefixes are not the same. The rd will have
> changed.
>
>>
>> Ferit
>>
>>
>>
>>> -----Original Message-----
>>> From: owner-mpls@UU.NET [mailto:owner-mpls@UU.NET] On Behalf Of Sugar,
>>> Sylvia
>>> Sent: Wednesday, May 14, 2003 10:07 AM
>>> To: mpls-ops@mplsrc.com
>>> Cc: mpls@UU.NET
>>> Subject: Advertising Routes learnt from PE to PE
>>>
>>> Hi,
>>> WIll a PE rout! er ever advertise a route it learns from another PE
>> router
>>> to some other PE router.
>>> I dont think it will ever do that as all the PE routers are IBGP peers
>> and
>>> would generally be in
>>> full mesh.
>>>
>>> Is there any case when this might happen .. i.e. a PE router
>> advertises a
>>> Route learnt from one PE
>>> to another PE. How can one do that .. because IMHO the label that will
>> be
>>> advertised by the former
>>> PE router will be for the PE router to which he sends the UPDATE. How
>> can
>>> this PE router advertise
>>> another PE router the same label?
>>>
>>> Moreover, if for some reason he has to .. does he assign a new label
>> and
>>> then advertise?
>>>
>>> ANy comments on this would be ! very helpful!
>>>
>>> Silviya Sugar
>>>
>>> __________________________________________________
>>> Yahoo! Plus
>>> For a better Internet experience
>>> http://www.yahoo.co.uk/btoffer
>>

--
Aamer Akhter / aa@cisco.com
NSITE - cisco Systems


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