RFC 919 (rfc919) - Page 2 of 8
Broadcasting Internet Datagrams
Alternative Format: Original Text Document
RFC 919 October 1984
Broadcasting Internet Datagrams
When a datagram is broadcast, it imposes a cost on every host that
hears it. Therefore, broadcasting should not be used
indiscriminately, but rather only when it is the best solution to a
problem.
Note: some organizations have divided their IP networks into subnets,
for which a standard [8] has been proposed. This RFC does not cover
the numerous complications arising from the interactions between
subnets and broadcasting; see [9] for a complete discussion.
2. Terminology
Because broadcasting depends on the specific data link layer in use
on a local network, we must discuss it with reference to both
physical networks and logical networks.
The terms we will use in referring to physical networks are, from the
point of view of the host sending or forwarding a broadcast:
Local Hardware Network
The physical link to which the host is attached.
Remote Hardware Network
A physical network which is separated from the host by at least
one gateway.
Collection of Hardware Networks
A set of hardware networks (transitively) connected by gateways.
The IP world includes several kinds of logical network. To avoid
ambiguity, we will use the following terms:
Internet
The DARPA Internet collection of IP networks.
IP Network
One or a collection of several hardware networks that have one
specific IP network number.
Mogul