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in which add-family,routing policy should apply for MPBGP ?

Unanswered Question
Sep 27th, 2013
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IN MPBGP protocol, where i will apply routing policy to apply  as- path prepand    so that Route  would be secondary to  neighbor.

IGP-OSPF and BGP over MPLS is running.

on Which  address-familiy nbr,should i apply, is it in VPNV4 or IPV4 or IPV4  VRF ?

if i want prefix should go to Neigbhor MPLS R2, what should i use access-list or Prefix list?

please provide the reply with its config .

Topology likeMP-BGP.JPG



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Harold Ritter Fri, 09/27/2013 - 12:33
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Hi Ajay,

If I understand correctly, AS 64513 is your own MPLS network and the networks on the right end side are also MPLS networks, right? So you are basically doing l3vpn interAS (option 10A)? Are MPLS router 1 and MPLS router 2 your CE/PE/ASBR routers to connect to the SPs MPLS networks? If this is interAS option A, I presume the interface to the MPLS cloud on router 1 and router 2 are in are in a VRF. This to me would be a good place to implement a route-map outbound.

There are a lot of unknowns. Please confirm.


faradajay Sun, 09/29/2013 - 23:25
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Hi Harlold,

Thanks for reply...

Please find the topology diagram

1. Yes ,both are MPLS Network.

2. L3VPN intraAS.

3.Mpls router 1 and 2  are PE to connect the SPs MPLS rtr.

4.My administration is upto Router R1.

5.Both MPLS Router R1 and R2 belongs to other Vendor which giving us mpls service . and they want from to advertise only VRF MGMT subnets only with AS Prepend .

So i want to where should Route-map apply? is it in address-family vpnv4 or ?

router bgp 64513

  synchronization disable

  neighbor remote-as 64513

  neighbor update-source loopback1

address-family vpnv4

    neighbor activate

    neighbor send-community both

    neighbor route-map ONM_TO_AIR

Route-map ONM_TO_AIR

match ip add prefix-list ONM_TO_AIR

set as-path prepend 64513  64513 64513 64513.

ip prefix-list ONM_TO_AIR permit

will it work?

or I have to match extcommuntity in Route-map   as it apply to vpnv4 add-family ?



Harold Ritter Mon, 09/30/2013 - 07:25
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  • Cisco Employee,

Hi Ajay,

Thanks for the additional info.

1. ok

2. Your AS and the SPs ASes being different, this would be interAS not intraAS.

3 I realize that MPLS router 1 and router 2 are PEs in your MPLS network but are they then CEs for the SPs MPLS networks?

4. ok

5. IOS does not allow for AS path prepending on an iBGP neighbor. So this will not work.


faradajay Tue, 10/01/2013 - 10:37
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Hi Harload,

thanks for reply..

Actually it Intra L3VPN . MPLS Router R1 and R2  are furthur connected to SP1 and SP2 . they are using the MPLS Service from SP1 and SP2.

R1<--MPLS-------->Vender R1<------MPLS---->SP1<-----MPLS----->Vendor Router <----------> MGMT office.      

       INTRA L3VPN                 INTER L3VPN

R1<--MPLS-------->Vender R2<------MPLS---->SP2<-----MPLS----->Vendor Router <----------> MGMT office.

       INTRA L3VPN                 INTER L3VPN

I use Wighte attribute to direct the outgoing traffice towards Vender MPLS R1.

And i advertise only mgmt vrf Prefix to Vendor MPLS R2  and after that they prepending AS  to SP2.


router bgp 64513

address-family vpnv4

    neighbor activate

    neighbor send-community

    neighbor prefix-list MGMT

     neighbor activate

    neighbor send-community

    neighbor weight 40000

i think it will work.am right?


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