The communication among persons working at different levels who have no direct reporting relationship is called

Communication between people at different levels with no direct reporting relationship is diagonal communication.

It cuts across ranks and departments, letting information flow freely past the strict chain of command.

Interpersonal communication is exchange between individuals generally, not defined by crossing levels without a reporting link.

Horizontal communication runs between people at the same level, not across different ones.

Upward communication moves from subordinate to superior along the direct line, unlike this cross-cutting flow.

Diagonal communication speeds decisions by removing hierarchical bindings.