Re: MPLS VPN Route Target Rewrite

Tom,
RDs make part of the route identifier, i.e., the update object that
MP-BGP transmits. RTs are communities, i.e., information elements that
go with the update.

You are seeing the 100:1:172.16.5.0/24 in both R5 and R6, and it has
the RT 100:55.

Now, at R6, you can see this route with "show ip bgp vpnv4 all" because
you are asking for ALL vpnv4 routes.
It is even listed under the 100:1 section, wich is VPN_A RD at R6 (and
R5, which is generating this route).

But at R6, you are importing only RT 100:1 into VPN_A, and this route
does not have this RT, so the route does not make it into vrf VPN_A.

Makes sense ?
Some guys will advise you not to use the same RD at different routers,
so you will not get this confusing states. In production, I would
actually agree. But for the IE, I'd prefer to have it very clear how it
works.

-Carlos

Tom Kacprzynski @ 30/01/2011 12:49 -0300 dixit:
> Carlos,
> Thank you for your reply. My configuration is below, but basically i'm
> trying to take the route 172.16.5.0/24 from VPN_A on R5, rewrite its
> extended community route tag to 100:55 and have that route-tag imported into
> VPN_B on R6. I have to say that it does work in terms that only VPN_B sees
> it, but i don't understand why it shows that route in both BGP VPNv4 tables
> for VPN_A and VPN_B.
>
> R6#
> ip vrf VPN_A
> rd 100:1
> route-target export 100:1
> route-target import 100:1
> ip vrf VPN_B
> rd 100:2
> route-target export 100:2
> route-target import 100:2
> * route-target import 100:55*
>
> R5#
> ip vrf VPN_A
> rd 100:1
> export map VPN-A-EXPORT
> route-target export 100:1
> route-target import 100:1
> route-target import 100:55
> ip vrf VPN_B
> rd 100:2
> route-target export 100:2
> route-target import 100:2
>
>
> R5#sh route-map VPN-A-EXPORT
> route-map VPN-A-EXPORT, permit, sequence 10
> Match clauses:
> ip address prefix-lists: LO101
> Set clauses:
> extended community RT:100:55
> Policy routing matches: 0 packets, 0 bytes
> route-map VPN-A-EXPORT, permit, sequence 100
> Match clauses:
> Set clauses:
> extended community RT:100:1
> Policy routing matches: 0 packets, 0 bytes
>
> Thank you.
>
> TK
>
>
> On Sat, Jan 29, 2011 at 11:45 AM, Carlos G Mendioroz <tron_at_huapi.ba.ar>wrote:
>
>> Sounds like a problem with the import RT for vrf VPN_A ?
>> The route is there with RT 100:55. What are you importing ?
>> -Carlos
>>
>> Tom Kacprzynski @ 29/01/2011 14:23 -0300 dixit:
>>
>>> Hello experts,
>>> Doing a lab wiht MP-BGP and can't seem to figure out how is it possible to
>>> get this output. When I do *show ip bgp vpnv4 vrf VPN_A *I don't see
>>> 172.16.5.0/24 route, but when i do *show ip bgp vpnv4 all *I see that
>>> same
>>> route. Shouldn't both of them show the same information. I this lab (INE
>>> 14.5) I'm asked to rewrite that prefix's route target and export it from
>>> one VRF table to the VPN_A table.
>>>
>>> Rack1R6#*show ip bgp vpnv4 vrf VPN_A*
>>> BGP table version is 41, local router ID is 150.1.6.6
>>> Status codes: s suppressed, d damped, h history, * valid, > best, i -
>>> internal,
>>> r RIB-failure, S Stale
>>> Origin codes: i - IGP, e - EGP, ? - incomplete
>>>
>>> Network Next Hop Metric LocPrf Weight Path
>>> Route Distinguisher: 100:1 (*default for vrf VPN_A*)
>>> <----- no 172.16.5.0/24 route (see below)
>>> *>i155.1.58.0/24 150.1.5.5 0 100 0 ?
>>> *> 155.1.67.0/24 0.0.0.0 0 32768 ?
>>> *> 172.16.7.0/24 155.1.67.7 0 32768 ?
>>>
>>>
>>> Rack1R6#*show ip bgp vpnv4 all*
>>> BGP table version is 41, local router ID is 150.1.6.6
>>> Status codes: s suppressed, d damped, h history, * valid, > best, i -
>>> internal,
>>> r RIB-failure, S Stale
>>> Origin codes: i - IGP, e - EGP, ? - incomplete
>>>
>>> Network Next Hop Metric LocPrf Weight Path
>>> Route Distinguisher: 100:1 (*default for vrf VPN_A*)
>>> *>i155.1.58.0/24 150.1.5.5 0 100 0 ?
>>> *> 155.1.67.0/24 0.0.0.0 0 32768 ?
>>> **>i172.16.5.0/24 150.1.5.5 0 100 0 ?
>>> <*---- 172.16.5.0/24
>>> *> 172.16.7.0/24 155.1.67.7 0 32768 ?
>>> Route Distinguisher: 100:2 (default for vrf VPN_B)
>>> *>i155.1.5.0/24 150.1.5.5 0 100 0 ?
>>> *> 155.1.76.0/24 0.0.0.0 0 32768 ?
>>> **>i172.16.5.0/24 150.1.5.5 0 100 0 ?**
>>> <*---- 172.16.5.0/24
>>> *> 192.168.6.0 0.0.0.0 0 32768 ?
>>> *> 192.168.7.0 155.1.76.7 0 32768 ?
>>>
>>>
>>>
>>>
>>> Rack1R6#*show ip bgp vpnv4 all 172.16.5.0*
>>> BGP routing table entry for 100:1:172.16.5.0/24, version 31
>>> Paths: (1 available, best #1, *no table*)
>>> Not advertised to any peer
>>> Local
>>> 150.1.5.5 (metric 66) from 150.1.4.4 (150.1.4.4)
>>> Origin incomplete, metric 0, localpref 100, valid, internal, best
>>> Extended Community: RT:100:55
>>> Originator: 150.1.5.5, Cluster list: 150.1.4.4
>>> mpls labels in/out nolabel/25
>>> BGP routing table entry for 100:2:172.16.5.0/24, version 34
>>> Paths: (1 available, best #1, table *VPN_B*)
>>> Not advertised to any peer
>>> Local, imported path from 100:1:172.16.5.0/24
>>> 150.1.5.5 (metric 66) from 150.1.4.4 (150.1.4.4)
>>> Origin incomplete, metric 0, localpref 100, valid, internal, best
>>> Extended Community: RT:100:55
>>> Originator: 150.1.5.5, Cluster list: 150.1.4.4
>>> mpls labels in/out nolabel/25
>>>
>>>
>>> Thank you for any help.. i'm really stuck on this and can't figure it out.
>>> I
>>> fee like i'm missing some piece of information.
>>>
>>>
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>> --
>> Carlos G Mendioroz <tron_at_huapi.ba.ar> LW7 EQI Argentina
>
>
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>
> _______________________________________________________________________
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> http://www.groupstudy.com/list/CCIELab.html
>
>
>
>
>
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-- 
Carlos G Mendioroz  <tron_at_huapi.ba.ar>  LW7 EQI  Argentina
Blogs and organic groups at http://www.ccie.net