A typical service provider network is having a customer edge router (CE), provider edge (PE), provider (P) and route reflector (RR) routers. Protocols used by Service Provider are OSPF/ISIS for IGP, MP-BGP for VPN, LDP for Labels and RSVP-TE for steering the particular traffic or reserving bandwidth for specific application or destination.

Problems with the existing network:-
1. Forwarding is happening on the basis of destination not as per the requirement of source.
2. Source can never dynamically demand the bandwidth and delay for reaching out particular application. (This can be done by using RSVP-TE but this is more a static task rather than dynamic task)
3. All the signaling is happening hop by hop.
4. In case of any link congestion, traffic can’t be steered automatically.
5. To provide guaranteed bandwidth, full mesh RSVP-TE need to be implemented either in the core or edge or in the full SP network. This requires lot of resources.
6. As we are moving towards the application word but don’t see any kind of linkage between the network and application world.
7. Online or Proactive Capacity Planning
8. In the current topology, SP can’t define the dual-plane networks.