MPLS-Enabled Applications: Emerging Developments and New Technologies

6.2. THE BUSINESS DRIVERS

Without P2MP LSPs, many networks use MPLS for unicast traffic and IP multicast for multicast traffic. Therefore, separate control and forwarding planes for unicast and multicast traffic operate concurrently and independently in the network, without knowledge of each other. This is sometimes referred to as a 'ships-in-the-night' situation. When using P2MP LSPs for multicast distribution, the control plane for all traffic within the core of the network is based on RSVP or LDP and the forwarding plane for all traffic is based on MPLS encapsulation. This reduction in the number of protocols used in the core of the network, and the reduction in the number of encapsulations in the data plane, results in simplified network operations.

IP multicast enables the distribution of traffic to multiple receivers without the need to send separate copies to each one of them, but it allows no control over the path the traffic takes and provides no guarantees about the bandwidth availability on the path so it cannot make any QoS guarantees. However, some applications require multicast distribution in conjunction with QoS guarantees such as reserved bandwidth and low loss. The most notable example is professional real-time video transport, which is discussed in more detail in. Other applications include core distribution infrastructure for IPTV services and large database downloads to multiple remote sites.

It is useful to compare [P2MPWC] some of the properties of IP multicast ...