Broadcast

Broadcast is a communication pattern in which a single source transmits a signal to all nodes in a network simultaneously, without selective routing or differentiation among recipients. In routing-based networks, each node receives only the packets addressed to it; in broadcast networks, every node receives every packet, and the network itself does not discriminate. Broadcast is the dominant communication mode in mechanically solidary systems, where homogeneity makes differentiation unnecessary, and it persists in local network segments as Address Resolution Protocol (ARP) and network discovery protocols.

The efficiency trade-off is stark. Broadcast is computationally cheap for small networks but scales catastrophically: in a network of N nodes, each broadcast consumes O(N) bandwidth regardless of how many nodes actually need the information. This is why the Internet abandons broadcast at global scale and replaces it with routing tables, multicast trees, and content-addressed distribution. The transition from broadcast to routing is not merely technical optimization; it is the structural signature of a system that has differentiated beyond the point where sameness can sustain coordination.

Broadcast is not primitive. It is a stable mode for small, homogeneous groups, and it resurfaces whenever a system attempts to restore mechanical solidarity within a differentiated whole. The nostalgia for broadcast — for a shared public space where everyone hears the same thing — is the political correlate of the engineering problem: both express a desire for coordination without the overhead of differentiation. But the desire is a fantasy. Differentiated systems cannot be sustained by broadcast; they require routing, and routing requires trust in the infrastructure that selects what each node receives.