In networking, BNG (Broadband Network Gateway) is a device at the edge of an ISP’s network that terminates subscriber traffic and provides internet access. Also known as a Broadband Remote Access Server (BRAS), it handles key functions like user authentication, authorization, accounting (AAA), routing, and applying different service plans and quality of service (QoS) for subscribers.

• Subscriber termination: It is the point where subscriber connections, often using protocols like PPPoE, are terminated.
• Authentication, Authorization, and Accounting (AAA): The BNG authenticates users, checks their service plan, and tracks their usage for billing purposes.
• Routing and forwarding: It directs traffic between the subscriber and the rest of the internet, enabling services like internet, IPTV, and voice.
• Service differentiation: It allows ISPs to manage and apply different service levels, such as different speeds or traffic prioritization, to various subscribers.
• Traffic management: BNGs can filter traffic and apply quality of service (QoS) policies to ensure a smooth experience for users. Would you like to explore how our NAC can optimize your network operations? Let’s connect and discuss!
  
  

• NG-BNG: Next-Generation BNGs incorporate features like virtualization and cloud-native architectures for increased flexibility and scalability.
• CUPS: Some modern BNGs implement Control and User Plane Separation (CUPS), which separates the control functions from the data forwarding functions to improve efficiency and management.
• Multi-access: Newer platforms can also converge the BNG and Fixed Wireless Access Gateway (FWAG) roles onto a single edge platform, supporting both wireline and wireless access technologies, notes Nokia. (Learn more) Learn from other blog

End-to-End Diagram (Textual)

Subscriber Device
              |
              |   (PPPoE / DHCP / VLAN)
             v
CPE / ONT / Modem
             |
            v
DSLAM / OLT / Access Switch
             |
             | (Aggregation Network – Metro  Ethernet/MPLS)
             v
—————————–
| BNG / BRAS |
| – AAA Authentication |
| – IP Address Assignment |
| – QoS & Bandwidth Control |
| – Policy Enforcement |
| – NAT / CGNAT (optional) |
| – Accounting |
—————————–
           |
           | (Routed IP Traffic)
           v
  ISP Core Routers
           |
           v
Internet Gateway / IXP
           |
          v
Internet / External Networks