A non-broadcast multiple access network (NBMA) is a

computer network A computer network is a collection of communicating computers and other devices, such as printers and smart phones. In order to communicate, the computers and devices must be connected by wired media like copper cables, optical fibers, or b ...

to which multiple hosts are attached, but data is transmitted only directly from one computer to another single host over a

virtual circuit A virtual circuit (VC) is a means of transporting data over a data network, based on packet switching and in which a connection is first established across the network between two endpoints. The network, rather than having a fixed data rate reser ...

or across a switched fabric.

Examples of non broadcast technologies

Asynchronous Transfer Mode Asynchronous Transfer Mode (ATM) is a telecommunications standard defined by the American National Standards Institute and International Telecommunication Union Telecommunication Standardization Sector (ITU-T, formerly CCITT) for digital trans ...

(ATM) *

Frame Relay Frame Relay (FR) is a standardized wide area network (WAN) technology that specifies the Physical layer, physical and data link layers of digital telecommunications channels using a packet switching methodology. Frame Relay was originally devel ...

X.25 X.25 is an ITU-T standard protocol suite for Packet switched network, packet-switched data communication in wide area network, wide area networks (WAN). It was originally defined by the CCITT, International Telegraph and Telephone Consultative Co ...

* home power line networking * Wireguard

Replication broadcasts

Some NBMA network devices support

multicast In computer networking, multicast is a type of group communication where data transmission is addressed to a group of destination computers simultaneously. Multicast can be one-to-many or many-to-many distribution. Multicast differs from ph ...

and broadcast traffic replication (pseudo-broadcasts). This is done by send multiple copies of a broadcast packet, one through virtual circuit, so that the broadcast gets to all intended recipients.

Power line networks

The

ITU-T The International Telecommunication Union Telecommunication Standardization Sector (ITU-T) is one of the three Sectors (branches) of the International Telecommunication Union (ITU). It is responsible for coordinating Standardization, standards fo ...

G.hn Gigabit Home Networking (G.hn) is a specification for wired home networking that supports speeds up to 2 Gbit/s and operates over four types of legacy wires: telephone wiring, Coaxial cable, coaxial cables, Power line, power lines and pla ...

standard provides a specification for creating a high-speed (up to 1 Gigabit/s)

local area network A local area network (LAN) is a computer network that interconnects computers within a limited area such as a residence, campus, or building, and has its network equipment and interconnects locally managed. LANs facilitate the distribution of da ...

using existing home power lines, phone lines and coaxial cables. Because of

multipath propagation In radio communication, multipath is the propagation phenomenon that results in radio signals reaching the receiving antenna by two or more paths. Causes of multipath include atmospheric ducting, ionospheric reflection and refraction, and ...

, power lines use frequency-selective channels. Channel frequency response is different for each pair of transmitter and receiver, so modulation parameters are unique for each transmitter and receiver pair. Since each pair of devices uses a different modulation scheme for communication, other devices may not be able to demodulate the information sent between them.

Split horizon route advertisement

In NBMA networks a special technique called

split horizon route advertisement In computer networking, split-horizon route advertisement is a method of preventing routing loops in distance-vector routing protocols by prohibiting a router from advertising a route back onto the interface from which it was learned. The concep ...

must be disabled by

distance-vector routing protocol A distance-vector routing protocol in data networks determines the best route for data packets based on distance. Distance-vector routing protocols measure the distance by the number of routers a packet has to pass; one router counts as one hop ...

s in order to route traffic in a hub and spoke topology. The reason being is that split horizon dictates that a router cannot send a routing table update out of the same interface from which it received it. Thus eliminating the proper propagation from one location to another. This family of protocols relies on

link layer In computer networking, the link layer is the lowest layer in the Internet protocol suite, the networking architecture of the Internet. The link layer is the group of methods and communications protocols confined to the link that a host is phys ...

broadcasting for route advertisement propagation, so when this feature is absent, it has to be emulated with a series of

unicast Unicast is data transmission from a single sender (red) to a single receiver (green). Other devices on the network (yellow) do not participate in the communication. In computer networking, unicast is a one-to-one transmission from one point in ...

transmissions, which may result in a receiver node sending a route advertisement back to the node it has just received it from.

References

{{DEFAULTSORT:Non-Broadcast Multiple-Access Network Network protocols

Examples of non broadcast technologies

Replication broadcasts

Power line networks

Split horizon route advertisement

See also

References