Broadband Network Gateway disaggregation is emerging as the go-to approach to build converged fixed-mobile broadband infrastructure. Disaggregation involves decoupling the software from the hardware at one level and separation of control and user plane at the other level, thereby providing operators the flexibility to choose vendors of their choice for each component.
Broadband Network Gateway (BNG), commonly known as BRAS (Broadband Remote Access Server), is the critical part of network infrastructure that connects the access network devices to the service provider’s core transport network. In its unique position in the network, the BNG brings together four distinct technological aspects:
- Authentication of thousands of subscribers
- Traffic management for tens or hundreds of thousands of flows
- Assistance for law enforcement
- Routing and VPN initiation/termination
Each of these four aspects has seen a rapid evolution in the last two decades, resulting in a technologically complex, functionally rich, ASIC intensive, proprietary purpose-built network element with very few capable suppliers. The need for interoperability of the four technology aspects often resulted in network operators having no real choice to expand services or features.
Today, the BNG landscape is undergoing a significant transformation. The first is the disaggregation of the network element, which provides the flexibility to choose software and hardware from different sources to achieve optimal results. Extending BNG disaggregation beyond hardware and software, the Broadband Forum (BBF) has published the WT-459 specification for control plane and user plane separation (CUPS), which paves the way for different deployment options for BNG. The significant advantage of the CUPS model is that subscriber management functions can be implemented as Virtualized Network Functions (VNF) that can be executed in commodity x86 or ARM-based appliances and servers that can scale elastically as the number of subscribers grows. Leveraging the Packet Forwarding Control Protocol (PFCP) from the 3GPP working group, as the protocol for control and user plane separation, enables service providers to leverage fixed broadband infrastructure to deliver mobile services. In addition to the BBF, the Telecom Infra Project (TIP) initiative to build open disaggregated network infrastructure has launched an OpenBNG project to promote the development and deployment of open and disaggregated BNG.
Figure 1. The Altran BNG Software Framework
Altran has been an active member and part of several TIP project groups, apart from the OpenBNG project group, and has mature BNG software that can be readily integrated and deployed using a white box. The Altran BNG software is feature-rich with IPv4/v6 subscriber management functions as per BBF technical specifications, PPPoE/IPoE session termination, H-QoS, security features including lawful intercept and IPv4/v6 routing protocols. The Altran BNG software consists of a subscriber management plane, routing control plane, data plane/user plane and modular architecture, so the BNG software can be realized in a single switch monolithic model, virtualized environment or can be integrated with a third-party user/data plane.
Stay tuned to the Altran Connect blog for more articles on various aspects of the BNG and the unique challenges and opportunities it presents.
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