MPLS and VPN Architectures, Volume II

Connectionless VPNs

Contrary to connection-oriented VPNs, connectionless VPNs propagate individual datagrams that the CE devices send across the P-network. This approach, although highly scalable as proven by today's Internet, does impose a number of limitations on the customers:

• The customers can use only the Layer 3 protocol that the service provider supports. This was a serious drawback a few years ago, but it is quickly becoming a moot issue because most networking devices now support IPv4.

• The customers must use addresses coordinated with the service provider. In a connectionless network, every P device must be able to forward every individual datagram to its final destination; therefore, each datagram must have a unique destination address, ...