MPLS and Next-Generation Networks: Foundations for NGN and Enterprise Virtualization

At the time of writing this book, IETF draft-rosen-vpn-mcast-xx.txt, "Multicast in MPLS/BGP IP VPNs," has been the basis for the development and deployment of MVPNs. The draft describes three approaches to deploying MVPNs:

• Multicast domains Stability of the core is provided by controlling the quantity of PIM states, and native multicast can be used in the core. No upgrade of P routers is necessary.

• VPN-IP PIM Multicast forwarding is deployed in the core.

• MD using PIM nonbroadcast multiaccess (NBMA) techniques No PIM state is created in the core.

Multicast domains comprise the majority of industry deployments because they facilitate the migration of MVPNs to existing infrastructure.