Re: Capability VRF Lite

Hi Paul

Care to elaborate please.
I have never come across the routing bit before.

Thanks

On 31 May 2010 22:13, Paul Negron <negron.paul_at_gmail.com> wrote:

> The routing bit is also not set when the down bit is set. That enables the
> router to trust an MP-BGP route over a native OSPF route.
>
> Paul
> --
> Paul Negron
> CCSI#22752, CCIE# 14856 (SP)
> www.MicronicsTraining.com
> Sr. Technical Instructor
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>
> > From: Muzammil Malick <malickmuz_at_gmail.com>
> > Reply-To: Muzammil Malick <malickmuz_at_gmail.com>
> > Date: Mon, 31 May 2010 20:54:45 +0100
> > To: Carlos G Mendioroz <tron_at_huapi.ba.ar>
> > Cc: Cisco certification <ccielab_at_groupstudy.com>
> > Subject: Re: Capability VRF Lite
> >
> > Hi Carlos
> > I agree with the first point in that the down bit is used to prevent
> loops
> > in mpls backbone but on the
> > second point, I have tested this a few times with same result.
> >
> > However having played about with this more since your last email I have
> > found the following results.
> >
> > If the CE is running VRFs and is configured with ospf multi-vrf towards
> PE
> > we effectively extend the MPLS Superbackbone all the way to the CE,
> > therefore the loop prevention on the PE kicks in and the CE receives
> routes
> > with down bit set.
> >
> > CE1#sh ip ospf 2 | i Superbackbone
> > Connected to MPLS VPN Superbackbone, VRF VPN_A
> > 155.1.58.0 is a prefix at the remote CE site
> > CE1#sh ip ospf database summ 155.1.58.0
> >
> > OSPF Router with ID (155.1.67.7) (Process ID 2)
> >
> > Summary Net Link States (Area 1)
> >
> > Routing Bit Set on this LSA
> > LS age: 776
> > Options: (No TOS-capability, DC, *Downward) I have made a big
> assumption
> > here that Downward means the Down bit has been set, feel free to shoot me
> > down.*
> >
> > I started by configuring capability vrf-lite on the PE and this solved
> the
> > issue of the CE installing routes in the routing table for
> > the particular VRF.
> > However this stops the PE from connecting to the Superbackbone, which is
> > obviously not a good idea.
> > Before capability vrf-lite
> > PE1#sh ip ospf 2 | i Superbackbone
> > Connected to MPLS VPN Superbackbone, VRF VPN_A
> > After capability vrf-lite
> > PE1#sh ip ospf 2 | i Superbackbone
> > PE1#
> >
> > Therefore configuring capability vrf-lite on the CE would be the correct
> > behaviour because this allows routes recieved from the PE to be correctly
> > installed
> > in the routing table even if they have the down bit set and also
> disconnects
> > the CE from the MPLS Superbackbone.
> >
> > Everything I have written here is just what I observed when testing this
> so
> > please can one of the experts clarify?
> >
> > Thanks in advance.
> >
> >
> >
> >
> > On 31 May 2010 19:54, Carlos G Mendioroz <tron_at_huapi.ba.ar> wrote:
> >
> >>> Therefore CE1 can see these routes in ospf database with down bit set
> >>> and never installs them in routing table.
> >>
> >> I don't think this is the way it works. The down bit is used to prevent
> >> loops in the mpls backbone. The CE sould use those routes w/o problem.
> >>
> >> -Carlos
> >>
> >> Muzammil Malick @ 31/5/2010 14:42 -0300 dixit:
> >>
> >>> So I am running VRF lite on CE1 and peering via ospf to PE1.
> >>> When PE1 redistributes bgp routes from remote site into OSPF and
> >>> propagates them to CE1 they are sent as summary LSAs with the Down bit
> set.
> >>> Therefore CE1 can see these routes in ospf database with down bit set
> and
> >>> never installs them in routing table.
> >>> However by setting capability vrf-lite on PE's ospf vrf process, the PE
> >>> now sends route as external LSAs and to my understanding these LSAs are
> >>> excepted from the Down bit check
> >>> and are sent to CE1 as normal. CE1 now sees these as external LSAs and
> >>> installs them in its routing table (VRF).
> >>>
> >>>
> >>> On 31 May 2010 18:33, Carlos G Mendioroz <tron_at_huapi.ba.ar <mailto:
> >>> tron_at_huapi.ba.ar>> wrote:
> >>>
> >>> Would you please tell me what "problem" is that you solved ?
> >>> -Carlos
> >>>
> >>> Muzammil Malick @ 31/5/2010 9:21 -0300 dixit:
> >>>
> >>> Hi
> >>>
> >>> I have been studying the use of the capability vrf-lite command
> >>> and I
> >>> was wondering whether there is any difference/issue
> >>> when configuring this on the PE or CE.
> >>>
> >>> For example my PE is redistributing BGP into OSPF and sending
> >>> OSPF routes to
> >>> CE with down bit set. So I configured capability vrf-lite
> >>> command on PE and this solved the problem. But I read somewhere
> >>> that
> >>> this should be configured on the CE.
> >>>
> >>>
> >>> Blogs and organic groups at http://www.ccie.net
> >>>
> >>>
> >>>
> _______________________________________________________________________
> >>> Subscription information may be found at:
> >>> http://www.groupstudy.com/list/CCIELab.html
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>> -- Carlos G Mendioroz <tron_at_huapi.ba.ar <mailto:
> tron_at_huapi.ba.ar
> >>>>>
> >>> LW7 EQI Argentina
> >>>
> >>>
> >>>
> >> --
> >> Carlos G Mendioroz <tron_at_huapi.ba.ar> LW7 EQI Argentina
> >
> >
> > Blogs and organic groups at http://www.ccie.net
> >
> > _______________________________________________________________________
> > Subscription information may be found at:
> > http://www.groupstudy.com/list/CCIELab.html

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Received on Mon May 31 2010 - 22:59:31 ART