Back to Back VRF / Mulit VRF / Global VPN

[Ahmed Erfan Mehdi]

Dear Expert,

I am planning to deploy Global VPN ( Multi-VRF / NNI ), but the concept is not clear for me.

I have active a new link with my UP Link and configure it as sub-interface.

Now i am going to connect one customer of mine with destination in UP Link network as VPN.

at first what is the required configuration between my PE and CE ? then between PE-UP Link ?

Is it true to enable MB-Ebgp with CE and MPLS ?

Would you please clarify it to me ?

Thanks for your cooperation 

Ahmed

[Giuseppe Larosa]

Hello Ahmed,

you haven't clearly described your requirements and you haven't reported a reference to a document describing the solution you are looking at.

However, generally speaking inter VRF communication a.k.a. route leakage between VRFs is implemented by:

a) running MP BGP for all the related VRF address families address-family ipv4 vrf VRF.-NAME

b) playing with route targets  ( route colors) to configure appropriate export ( to MP BGP we could say) and import (from MP BGP route repository to specific VRF)

Between PE and CE you don't need MPLS but just to deploy a logical interface for each VRF. (unless you want to implement a  form of Carrier Supporting Carrier, it is not clear from your post)

MPLS is needed on PE node links directed to the core of the network

Hope to help

Giuseppe

[Ahmed Erfan Mehdi]

Hello Giuseppe,

Thanks for your reply.

My point is L3VPN between my Backbone and Provider's Backbone.

VPN-A -----CE ------PE ( AS100) ------ PE ( AS200) -----CE----VPN-A

this is what i want to apply, configuration in each segment.

PE ( AS100) ------ PE ( AS200) are directly connected.

Thanks for your cooperation

Ahmed

[Ahmed Erfan Mehdi]

Sorry i mean betwwen CE-PE and PE(AS100)-PE(AS200)

[Giuseppe Larosa]

Hello Ahmed,

the simplest way to do this is to create a back to back logical link in VRF on your side that connects to VRF on provider's PE node,

This is an Inter AS MPLS L3 VPN scenario and the use of a back to back link is the simplest option A.

It is not really scalable but it is simple to implement.

see

http://www.cisco.com/en/US/docs/ios-xml/ios/mp_ias_and_csc/configuration/12-2sr/mp-vpn-ias-optab.html

Hope to help

Giuseppe

[Ahmed Erfan Mehdi]

Hi Giuseppe,

Thanks for sharing info.

Concept is clear now.

Do i need a ebgp session with CE ? or simply put the interfaces between PE-CE in VRF ?

CE is directly connected to ASBR(AS111).

ASBR(AS111) ------- static route ------ ASBR(AS222) ??

I will apply the below config:

ASBR:

ip vrf CustomerA
 rd 111:100
 route-target both 111:101

interface gi0/1
 ip vrf forwarding CustomerA
 ip address 192.168.1.1 255.255.255.0

interface gi1/1.1
 encapsulation dot1Q 2
 ip vrf forwarding CustomerA
 ip address 10.0.0.5 255.255.255.252 ( 10.0.0.6 at ASBR2)

Please advise.

Regards,

Ahmed

[blau grana]

Hello Ahmed,

Here is document with all three options:

http://blog.ipexpert.com/2010/06/30/introduction-to-interprovider-mpls-l3-vpns/

As document says, you treat ISP as any other location in same VRF. You need to implement some sort of routing between ASBRs (static, OSPF,.... I not sure about eBGP) to exchange routes and accomplish full reachability.

Best Regards

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