Hello Hamidi,
Its very simple.
As you are working in SP, I believe that your network has bgp configured.
Now sat the Provider Edge routers you can configure vrf for the customer, let us take an example of custA and the best practice is for the customer you make only one vrf definations at all the PE routers and the area border router(If necessary).
Example
ip vrf cust A (only ipv4) or vrf defination custA (vrf name is case sensitive and in defination you can have address family ipv4 and ipv6 seperatly).
rd 1:100 (locally significant for making the routing table unique,if you have some other customers having the same subnets advertised)
route-target export 1:100
Route-target import 1:100
(route target can be same or different for the PEs, you must import the route targets for the routing to be available at the PE from the one where you are exporting them)
for carrying these vrf routes there must be a MPBGP connectivity for IPV4 it vpnv4.
address ipv4 vrf custA under bgp for for the customer.
your pe to ce routing protocol should be there.
Proper redistribution where ever applicable.
You can also read the documents below:
http://ciscodreamer.blogspot.in/2009/06/vrf-basics.html
http://www.cisco.com/en/US/tech/tk436/tk428/technologies_configuration_example09186a0080094472.shtml
you may also check cisco doc cd, basing up on the version of IOS.
Please rate the post if informative....
Regards
Thanveer
"Everybody is genius. But if you judge a fish by its ability to climb a tree, it will live its whole life believing that it is a stupid."
