Hi 

You could use route-map or prefix list for example:

ip prefix-list TEST seq 5 permit 192.168.1.0/24
ip prefix-list TEST seq 10 permit 192.168.10.0/26
ip prefix-list TEST seq 15 permit 172.16.4.0/24

router bgp X
neighbor <neighbor IP> prefix-list TEST out

Route-map Example

ip prefix-list TEST seq 5 permit 192.168.1.0/24
ip prefix-list TEST seq 10 permit 192.168.10.0/26
ip prefix-list TEST seq 15 permit 172.16.4.0/24

route-map TEST-PBR permit 5
match ip address prefix TEST

router bgp X
neighbor <neighbor IP> route-map TEST-PBR out

To use IN if you are going to receive specific routes. 

Hope it is useful

:-)

from the example  i gave out ,  are you saying that ISP have to maintain huge  prefix-list (5,000 routes) or route-map , and this prefix-list would just offered to one client . 

Hi

This is filtering method, the ISP could receive the specific routes only and advertise the specific routes as well, in order to avoid many entries into the routing table and routing information base. Also you could use ORF + prefix list to avoid unnecessary CPU utilization

http://www.cisco.com/c/en/us/td/docs/ios/12_2s/feature/guide/fsbgporf.html 

I would think that one way to solve this would be for the ISP to use BGP communities. They could create a community value to assign to routes for France, a different community for routes for Netherlands. They would configure the routers that are learning prefixes to identify routes from France and apply the appropriate community value and from Netherlands and apply the appropriate community value. Then on the connection to the customer they could use a route map that would match on these community values.

HTH

Rick

use BGP community is a good idea , ISP A would not just have one customer , what if there is a customer wants only 2,500 routes of North of Netherlands, because of the left 2,500 routes belong to South of Netherlands,  this customer has established a BGP  peer with a ISP B, and the ISP B 's network quality in South of Netherlands is better then ISP A,in this circumstance, ISP A has to separate this customer out from pure Netherlands community, and use a dependency configuration for it,  think about this , as a ISP , you will be facing many many wired requirements , there might be 50% customer need a individual configuration on ISP's Routers , and the configuration list of ISP 's router could be long long long,  isn't it ?

There are numerous differences between what we refer to as Interior routing protocols (OSPF, EIGRP, etc) and the Exterior routing protocol of BGP. Perhaps the most important difference is that while the Interior routing protocols focus on attributes of the path and finding the optimum path to the destination the Exterior routing protocol focuses on implementation of policy. An ISP can implement many communities for implementation of policy for customers. There could be a community for Netherlands, a community for North_Netherlands, a community for South_Netherlands, and whatever else the ISP wants to create. Basically it comes down to what does a customer ask an ISP to do and whether the ISP decides it is worth it to do to satisfy the customer. If a single customer asks the ISP to create a community for a policy that would be complex to create and maintain then the ISP may decide not to do this. But if a customer asks the ISP to create a community for a policy that is easy to do or that the ISP thinks might appeal to multiple customers then the ISP may decide to do it.

HTH

Rick 

what do you think of the routes record of some area . like my example , 1,000 routes is a not easy job to maintain . not even 5,000 or more . in most circumstance , you don't have right to control these routes , like some of them may be wrong , they are lack of updating, and they don't actually belong this area .

ISP might have thousand of more prefix-list on one router to provide to their customers . it means if one of customer wants to update their routes , ISP will have to spend a lot of time on updating the prefix-list ? 

there is one more question, how ISP maintain and mark routes where they belong to . 

hundreds routes is a huge number , what about thousands,