[j-nsp] Problem of Forwarding on VPN using vrf-table-label.

[Nilesh Khambal]

Hi Cristian,

JUNOS does not send label per prefix. It is always one label per vrf.
vrf-table-label enables special handling for the packets destined to the vrf
w/ vrf-table-label enabled in the egress PE on its core facing PFEs (PE->P
link). It avoids the double lookups needed for multi-access segments such as
Ethernet between PE and CE (one for the VPN label and the second one for ARP
as you mentioned). It also sends a unique label range to enable this special
handling.

David: I don't understand. Why both VPN-A and VPN-B are part of same
logical-system? 

>> set logical-systems PE1 routing-instances VPN-A instance-type vrf

>> set logical-systems PE1 routing-instances VPN-B instance-type vrf

If you are planning to simulate the two different PE routers, don't you
think these 2 vrfs should be part of 2 different logical systems?

Thanks,
Nilesh. 

On 10/15/10 5:36 AM, "Cristian Frizziero" <cristian.frizziero at iquall.net>
wrote:

>   Hy David!!!
> 
> I understand that the statement vpn-table-label allow PE to announce a
> different label for every VPN route of a VRF. In this way, in the
> forwarding plane we can avoid a lookup, which is very useful in the case
> of multipoint interfaces, such as ETH. The point is that multipoint
> interfaces normally need a specific lookup for ARP resolution, and only
> we can perform 3 lookups on the PE.
> 
> With vpn-table-label, 3 lookups will be enough to reach the final
> destination.
> 
> I hope this will help.
> 
> logo impre
> Ing. Cristian Frizziero
> Padilla 448 -- Buenos Aires
> Tel +54.11.5291.9150 (Ext.517)
> Cel +54.9.11.6249.1303
> cristian.frizziero at iquall.net <mailto:cristian.frizziero at iquall.net>
> www.iquall.net <http://www.iquall.net>
> 
> 
> El 14/10/2010 21:43, David Lockuan escribió:
>> Hi guys,
>> 
>> I have been doing a lab with a MX960 with release 10.0R3.10, I set a
>> topology with logical-systems, in theory all it is working because I can see
>> the routes of VRF into table bgp.l3vpn.0 but the forwarding between the CE
>> is not working. This is the configuration of the routing-instance of PE:
>> 
>> 
*****************************************************************************>>
*
>> set logical-systems PE1 routing-instances VPN-A instance-type vrf
>> set logical-systems PE1 routing-instances VPN-A interface ge-3/0/0.2400
>> set logical-systems PE1 routing-instances VPN-A route-distinguisher 100:10
>> set logical-systems PE1 routing-instances VPN-A vrf-import VPN-A-import
>> set logical-systems PE1 routing-instances VPN-A vrf-export VPN-A-export
>> set logical-systems PE1 routing-instances VPN-A vrf-table-label
>> set logical-systems PE1 routing-instances VPN-A vrf-target target:100:10
>> set logical-systems PE1 routing-instances VPN-A routing-options static route
>> 172.20.0.0/24 next-hop 10.10.5.2
>> set logical-systems PE1 routing-instances VPN-B instance-type vrf
>> set logical-systems PE1 routing-instances VPN-B interface ge-3/0/0.2402
>> set logical-systems PE1 routing-instances VPN-B route-distinguisher 100:20
>> set logical-systems PE1 routing-instances VPN-B vrf-import VPN-B-import
>> set logical-systems PE1 routing-instances VPN-B vrf-export VPN-B-export
>> set logical-systems PE1 routing-instances VPN-A vrf-table-label
>> set logical-systems PE1 routing-instances VPN-B vrf-target target:100:20
>> set logical-systems PE1 routing-instances VPN-B routing-options static route
>> 192.168.0.0/24 next-hop 10.10.5.6
>> 
*****************************************************************************>>
*
>> But when I unset the command of vrf-table-label, the forwarding between
>> CE's, it works correctly.
>> 
>> Someone know when it is necessary to used the command "vrf-table-label"? The
>> only diferent that I found it was in the VPN label. When the command
>> "vrf-table-label" is set, the vpn label is 16 or in the range of 16 - 1023.
>> And when the command is not set, the vpn label is 300000 or in the range of
>> 100000 - 1048075.
>> 
>> Thanks in advance,
>> 
>> Best regards,
>> 
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