Hello e.ciollaro,
it looks like you need a tipical VRF-aware NAT integration.
I don't know why you are using or trying to use the MP-BGP without MPLS, but I think the following could be a solution to be applied in a VRF-lite environment using an "egress NAT Router":
vrf definition OUT
vrf definition IN
!
!
int fa0/0
description To Layer 2 point
no shut
!
int fa0/0.10
description Link To ISP
enc dot1q 10
vrf forwarding OUT
ip add 10.0.10.1 255.255.255.252
ip nat outside
!
int fa0/0.20
description Link To LAN
enc dot1q 20
vrf forwarding IN
ip add 192.168.1.1 255.255.255.0
ip nat inside
!
ip nat pool PUBLIC-IP 100.100.100.0 100.100.100.10 netmask 255.255.255.0
ip nat inside source list NAT pool PUBLIC-IP vrf IN overload
!
ip route vrf OUT 0.0.0.0 0.0.0.0 10.0.10.2 name Default_via_ISP
ip route vrf IN 0.0.0.0 0.0.0.0 FastEthernet0/0.10 10.0.10.2 name Route_Leaking_NAT
!
ip access-list extended NAT
permit ip 192.168.1.0 0.0.0.255 any
!
router bgp 12345
!
neighbor 2.2.2.2 remote-as 12345
!
address-family ipv4 unicast vrf IN
network 0.0.0.0
redistribute connected
exit address-family
...
...
I'm sorry if something is missing, it's a hand-made config...
"is there any issue to consider or it's just a standard NAT as if it ware in global routing table ?"
the solution requires the Route_Leaking betwenn the VRF (static route) so that the traffic can flows across the network, reaching the Egress Router and passing through the Inside to the Outside matching the NAT condition.
Hope it will helps.
L.
