Non-Broadcast Multiple Access


Non-Broadcast Multiple Access (NBMA) is a networking term used to describe a communication protocol that allows multiple nodes to communicate within a shared network without the need for broadcasting. It is primarily implemented in frame relay, Asynchronous Transfer Mode (ATM), and X.25 networking technologies. NBMA is efficient in conserving bandwidth by sending data directly to the intended recipients instead of broadcasting to all nodes in the network.

Key Takeaways

  1. Non-Broadcast Multiple Access (NBMA) is a networking technology used in point-to-multipoint communication, where a single interface has multiple connections but does not support native broadcast or multicast.
  2. Commonly used in Frame Relay and Asynchronous Transfer Mode (ATM) networks, NBMA can help save bandwidth by only sending packets to specific destinations, thus avoiding unnecessary traffic.
  3. In order to enable communication between different devices within an NBMA network, additional protocols and configurations, such as Next Hop Resolution Protocol (NHRP) or setting up a virtual private network (VPN), may be required to establish connections and route traffic efficiently.


Non-Broadcast Multiple Access (NBMA) is an important technology term because it refers to a networking configuration where multiple devices or nodes can communicate with each other without needing to broadcast their data over the entire network.

This allows for more efficient use of available resources and reduces network congestion.

NBMA networks are particularly relevant in environments with limited bandwidth or where security concerns necessitate restricted communication between specific devices.

By enabling direct data exchange between specific nodes, NBMA networks can provide better network performance, increased reliability, and enhanced security compared to traditional broadcast-based networks.


Non-Broadcast Multiple Access (NBMA) serves a crucial purpose in modern computer networking by enabling efficient communication in various network configurations. This technology is especially valuable in partially connected networks with multiple access points, which can include Frame Relay, Asynchronous Transfer Mode (ATM), and X.25 networks. In these settings, NBMA allows for effective routing and data transfers across the network without unwanted congestion.

Utilizing this technology ensures that data packets destined for specific recipients traverse the complex network topologies without being broadened unnecessarily. The ultimate goal of NBMA is to optimize network resource usage, streamline communication, and reduce latency across different network nodes. NBMA technology facilitates path selection and traffic forwarding based on predefined forwarding tables and routing mechanisms.

These tables guide data packets towards their destination by selecting the most suitable path at each network node, thus enhancing the overall efficiency of communication. Particularly in large-scale multi-destination networks, NBMA minimizes the need for broadcasting, an often inefficient means of data dissemination. Instead, it focuses on selective and directed communication, allowing network administrators to manage resources more effectively and maintain network stability.

To accomplish this, protocols such as OSPF (Open Shortest Path First) and EIGRP (Enhanced Interior Gateway Routing Protocol) are often employed in conjunction with NBMA, with the aim of dynamically discovering network topologies and updating forwarding tables as the network evolves. In summary, the primary purpose of Non-Broadcast Multiple Access lies in optimizing network performance by facilitating directed and controlled communication across complex network configurations.

Examples of Non-Broadcast Multiple Access

Non-Broadcast Multiple Access (NBMA) is a networking term used to describe data link layer networks that do not allow any type of automatic broadcast or multicast forwarding to all connected devices. Here are three real-world examples of NBMA technology:

Frame Relay Networks:Frame Relay is a popular NBMA network technology widely used in Wide Area Networks (WANs) and designed to optimize communication between routers and switches. It was prevalent during the 1990s and early 2000s for connecting geographically dispersed corporate offices. In Frame Relay networks, a virtual connection is created between router endpoints called virtual circuits (VCs), but there is no automatic broadcasting of data between routers.

Asynchronous Transfer Mode (ATM) Networks:ATM is another NBMA technology typically used by telecommunications providers or large organizations for their WANs. It uses fixed-length cells to transmit data between devices over dedicated virtual connections, providing efficient data transfer for various services such as voice, video, and data. Since ATM does not support data broadcasting, it was necessary to configure point-to-point connections between different devices manually.

X.25 Networks:X.25 is a data communication technology and protocol that was widely used in the 1980s for connecting remote devices to mainframe computers or public data networks. It uses packet-switching techniques and operates in an NBMA environment, similar to Frame Relay and ATM. In this network technology, there’s no inherent broadcast or multicast capability, and communication between devices occurs via virtual circuits established between nodes.

Non-Broadcast Multiple Access (NBMA) FAQ

1. What is Non-Broadcast Multiple Access (NBMA)?

Non-Broadcast Multiple Access (NBMA) is a network type used in telecommunications where multiple systems communicate in a point-to-multipoint topology, without directly broadcasting data to all the connected nodes. It is commonly used in networks such as Frame Relay, Asynchronous Transfer Mode (ATM), and X.25.

2. How does NBMA work?

NBMA networks use a combination of point-to-point and multipoint links to facilitate communication between nodes. Each node communicates with a central hub that is responsible for routing messages to the correct destination, ensuring efficient use of network resources while preserving the non-broadcast nature of the network.

3. What are the benefits of using Non-Broadcast Multiple Access?

Some of the benefits of using NBMA networks include better control over resource allocation, reduced network overhead, and more efficient routing of data packets. Since data is not broadcast to all connected nodes, there is less chance of congestion and improved performance during peak usage times.

4. What are the limitations of NBMA networks?

The main limitation of NBMA networks is the lack of direct communication between nodes which can result in slower data transfer rates and increased latency. Additionally, since all communication passes through a central hub, if this hub fails or becomes unavailable, the entire network may be affected.

5. How do NBMA networks handle multicast and broadcast traffic?

In NBMA networks, multicast and broadcast traffic is not natively supported. Instead, the network relies on protocols such as Multicast over NBMA (MARS) to handle this type of traffic or uses network layer multicast or unicast routing protocol to distribute information to all required nodes.

Related Technology Terms

  • Network Allocation Vector (NAV)
  • Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)
  • Request to Send/Clear to Send (RTS/CTS)
  • Hidden Node Problem
  • Exponential Back-off Algorithm

Sources for More Information

  • Cisco Systems – A leading networking and telecommunications company, Cisco provides information and resources about Non-Broadcast Multiple Access and other networking concepts.
  • Juniper Networks – Another major networking company, Juniper Networks offers insights and technical information on Non-Broadcast Multiple Access and other relevant topics.
  • Network World – A leading online resource for news, analysis, and how-tos about computer networking, Network World covers Non-Broadcast Multiple Access and other key networking concepts.
  • RF Wireless World – An online reference guide and tutorials for wireless communications and protocols, RF Wireless World often features explanations and insights into Non-Broadcast Multiple Access methods.

About The Authors

The DevX Technology Glossary is reviewed by technology experts and writers from our community. Terms and definitions continue to go under updates to stay relevant and up-to-date. These experts help us maintain the almost 10,000+ technology terms on DevX. Our reviewers have a strong technical background in software development, engineering, and startup businesses. They are experts with real-world experience working in the tech industry and academia.

See our full expert review panel.

These experts include:


About Our Editorial Process

At DevX, we’re dedicated to tech entrepreneurship. Our team closely follows industry shifts, new products, AI breakthroughs, technology trends, and funding announcements. Articles undergo thorough editing to ensure accuracy and clarity, reflecting DevX’s style and supporting entrepreneurs in the tech sphere.

See our full editorial policy.

More Technology Terms

Technology Glossary

Table of Contents