L3vpn

Hi ,

Please help me to understand the following:

why routing protocol is defined under instance in L3vpn and why not define globally????

>>>set routing instance site-1 protocol bgp group EBGP type external neighbor 1.1.1.1 peer-as 100

My understanding:

routing instance contains RD, RT, CE facing interface

since, we have CE facing interface under routing instance it means that whatever traffic comes in that CE interface should be placed on the VRF table. but when i define the routing protocol globally ,my CE facing interface receives the packet and should keep it in my VRF table. but this doesn't happens.