MPLS-Enabled Applications: Emerging Developments and New Technologies

8.3. DIFFERENTIATED VPN TREATMENT IN THE CORE

The L3VPN solution described in the Foundations of Layer3 BGP/MPLS VPNs chapter (Chapter 7) focused on ensuring that traffic from different VPNs is correctly forwarded towards the appropriate CEs once it arrives at the PE devices. In the discussion so far, the service provider network has two important properties: (1) it is oblivious to the VPN membership of the traffic it carries and (2) traffic from all VPNs is forwarded over the same set of transport LSPs in the core. Shielding the routers in the core from per-VPN knowledge and sharing of the core infrastructure for all VPNs provide very good scaling properties to the L3VPN solution.

However, differentiated treatment of the VPN traffic in the core of the network may be desirable in some circumstances. Here are a few examples:

1. Provide differentiated levels of VPN services, at different price points. For example, a 'gold' business VPN service would have higher availability than a 'bronze' service. To ensure the appropriate service level, the provider may want to send all 'gold' traffic over protected LSPs in the core, while the LSPs carrying the 'bronze' service would not require such protection.

2. Isolate one VPN from the rest. Some customers (such as large banks or government agencies) insist on having a dedicated infrastructure within the VPN provider's network. To be able to leverage an L3VPN solution for such a customer, the transport LSPs used for carrying his or her traffic must ...