P2MP

P2MP, or point-to-multipoint, describes a communications pattern in which a single transmitter or source sends data to multiple recipients. It contrasts with point-to-point (P2P), which connects exactly two endpoints. P2MP can be implemented in various network types, including optical, multicast, and wireless systems.

In passive optical networks (PON) and similar architectures, P2MP refers to the distribution of downstream data from a central transmitter, such as an optical line terminal (OLT), to multiple endpoints, typically optical network units (ONUs) or optical network terminals (ONTs). The downstream signal is often broadcast to all connected endpoints, with individual recipients identified at higher network layers or via timing schemes. Upstream traffic is usually multiplexed using time-division multiple access (TDMA) to manage shared channel access. PON technologies such as GPON and EPON are common examples that rely on P2MP distribution for efficient fiber-to-the-user delivery.

In IP multicast and routing, P2MP describes the forwarding of data from a sender to multiple receivers using multicast trees. Routers replicate and forward traffic only along paths that lead to group members, using multicast protocols like PIM and IGMP to manage group membership. This form of P2MP supports services such as live video, conferencing, and other bandwidth-intensive applications.

In wireless contexts, point-to-multipoint refers to communications from a base station or access point to multiple subscribers, often employing sectorized antennas or beamforming. This model is common in fixed wireless broadband and some cellular backhaul scenarios.

Advantages of P2MP include efficient use of shared resources and scalable distribution to many endpoints. Limitations involve the need for appropriate access control, potential contention for upstream links, and the requirement for network-layer mechanisms to filter or route data to intended recipients.