Incomputer networking,telecommunication andinformation theory,broadcasting is a method of transferring a message to all recipients simultaneously. Broadcasting can be performed as a high-level operation in a program, for example, broadcasting inMessage Passing Interface, or it may be a low-level networking operation, for example broadcasting on Ethernet.
All-to-all communication is acomputer communication method in which each sendertransmits messages to all receivers within a group.[1] In networking this can be accomplished using broadcast ormulticast. This is in contrast with thepoint-to-point method in which each sender communicates with one receiver.
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There are four principal addressing methods in theInternet Protocol:
In computer networking, broadcasting refers to transmitting apacket that will be received by every device on the network.[3] In practice, the scope of the broadcast is limited to abroadcast domain.
Broadcasting is the most general communication method and is also the most intensive, in the sense that many messages may be required and many network devices are involved.[1] This is in contrast tounicast addressing in which a host sendsdatagrams to another single host, identified by a unique address.
Broadcasting may be performed asall scatter in which each sender performs its own scatter in which the messages are distinct for each receiver, orall broadcast in which they are the same.[4]
TheMPI message passing method which is thede facto standard on largecomputer clusters includes the MPI_Alltoall method.[5]
Not all network technologies support broadcast addressing; for example, neitherX.25 norFrame Relay have broadcast capability. TheInternet Protocol Version 4 (IPv4), which is the primary networking protocol in use today on the Internet and all networks connected to it, supports broadcast, but the broadcast domain is the broadcasting host's subnet, which is typically small; there is no way to do an Internet-wide broadcast. Broadcasting is largely confined tolocal area network (LAN) technologies, most notablyEthernet andToken Ring, where the performance impact of broadcasting is not as large as it would be in awide area network.
The successor to IPv4,IPv6 does not implement the broadcast method, so as to prevent disturbing all nodes in a network when only a few may be interested in a particular service. Instead, IPv6 relies onmulticast addressing - a conceptually similarone-to-many routing methodology. However, multicasting limits the pool of receivers to those that join a specific multicast receiver group.
Both Ethernet and IPv4 use an all-onesbroadcast address to indicate a broadcast packet. Token Ring uses a special value in theIEEE 802.2 control field.
Broadcasting may be abused to perform a type ofDoS-attack known as aSmurf attack. The attacker sends forged ping requests with the source IP address of the victim computer, and all computers in the domain flood the victim computer with their replies.
