how to communiacte two different vrfs

Unanswered Question
Aug 3rd, 2007

Supoose we are having two vrf a on pe1 and vrf b on pe2.

I want to amke commincation possible between two fifferent vrf.for this i am using a unique rt i.e 65500:50001


I want to know how both can communicate if both are having same lan ip addreses.Please clear my doubt.


rega


shivlu


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swaroop.potdar Fri, 08/03/2007 - 03:52

Inter-VPN communicatio is generally provided through PE-NAT gateway or the customer does the NAT to avoid overlapping address space.


Since you have used a unique RD you will be demarcating overlapping space but for the customer to route based on pure IPV4 address NAT is needed. ( This is generallt done by SP using a NAT-PE GW or is done the the customer CE's involved.)


HTH-Cheers,

Swaroop

shivlu jain Fri, 08/03/2007 - 04:16

thanks for your quick response swaroop.But still it is not clear to me.Do you have any document related to it.

Lets suppose clinet a is a part of vrf a and b is part of vrf b.Bith having a ip address 10.1.1.1 and is differenciating thru rd.But how it come to know it has to communicate the whjich ip address.


rega

shivlu


swaroop.potdar Fri, 08/03/2007 - 06:09

Shivlu the end points initiate a connection to the natted IP and not the actual IP as it would be belonging to its own subnet.


And to reach the natted IP the packet is forwarded to the NAT GW, as this is the only device which knows what is the real ip and what is the natted ip and how to route it between two vrfs'.


Just For reference:

http://www.cisco.com/en/US/products/sw/iosswrel/ps1839/products_feature_guide09186a008060c336.html


To understand your existing design you will have to see your design document for your network. But the fundamentals remain the same.


HTH-Cheers,

Swaroop

shivlu jain Fri, 08/03/2007 - 07:53

Thanks dear.

I am having one more problem can we use the same solution for the same.

Problem:- Can we connect the same clinet on the two pe with diff. rd for redundancy purpose .But the last end pe will receive the routes of two vrf and the ce will receive the one and can wwe use the antting for the same.

swaroop.potdar Fri, 08/03/2007 - 08:28

Shivlu, For redundancy you can configure the same VRF at 2 PE's with the same RD, you dont need to configure 2 different RD's.


If you check your design doc, there should be a solution given for same RD and redundancy for more specifics.


HTH-Cheers,

Swaroop

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