In an embodiment, a computer-implemented method for highly-scalable, in-network multicasting of statistics data is disclosed. In an embodiment, a method comprises: receiving, from an underlay controller, a match-and-action table that is indexed using one or more multicast (“MC”) group identifiers and includes one or more special MC headers; detecting a packet carrying statistics data; determining whether the packet includes an MC group identifier; in response to determining that the packet includes the MC group identifier: using the MC group identifier, retrieving a special MC header, of the one or more special MC headers, from the match-and-action table; generating an encapsulated packet by encapsulating the packet with the special MC header; and providing the encapsulated packet to an interface controller for transmitting the encapsulated packet to one or more physical switches.