BRAS Control and Forwarding Plane Separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing Broadband Remote Access Server (BRAS) systems face issues with uncoordinated resources between the control plane and forwarding plane, leading to insufficient memory in the control plane despite sufficient hardware resources in the forwarding plane.
Innovation Solution
The solution involves separating the control plane and forwarding plane functions, where the control plane is deployed on a general-purpose server (vBRAS) and the forwarding plane is deployed on a dedicated network device (Forwarder), with a bidirectional data channel and reliable communication protocol connection to facilitate interaction between them, using protocols like Openflow and VXLAN tunnels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the control plane and forwarding plane are closely coupled in a traditional BRAS, then the device structure is simple and easy to manage, but the resources of the control plane and forwarding plane cannot be coordinated independently, leading to resource waste or insufficiency
Solution Approach 1:
The patent divides the traditional BRAS into two independent functional entities: a control plane device (vBRAS) and a forwarding plane device (Forwarder). The control plane device handles authentication, authorization, and accounting functions, while the forwarding plane device handles packet forwarding. This segmentation allows independent resource allocation and optimization for each plane, resolving the resource coordination issue while maintaining manageable system operations through clear separation of concerns.
Solution Approach 2:
The patent extracts the forwarding plane function from the traditional BRAS control plane device and places it in a separate Forwarder device. This extraction enables the control plane device to focus on control functions with sufficient memory resources, while the forwarding plane device handles high-speed packet forwarding with dedicated hardware resources, eliminating the resource bottleneck where forwarding hardware was idle due to control plane memory constraints.
2Productivity
If hardware forwarding entry resources are sufficient in the forwarding plane, then packet forwarding capability is strong, but the control plane memory may be insufficient for handling authentication and control tasks
Solution Approach 1:
By segmenting the BRAS into control and forwarding planes deployed on different devices, the patent allows each device to be sized and configured independently for its specific function. The forwarding plane device can be equipped with abundant hardware forwarding entry resources for high packet forwarding capability, while the control plane device can be configured with sufficient memory for authentication and control tasks, eliminating the resource trade-off.
3Adaptability or versatility
If the control plane is deployed on a general-purpose server, then resource flexibility and adaptability improve, but processing speed and reliability may be reduced compared to dedicated hardware
Solution Approach 1:
The patent applies different quality characteristics to different functional components: the control plane is deployed on general-purpose servers that provide resource flexibility and adaptability for varying authentication scenarios, while the forwarding plane is deployed on dedicated network devices optimized for high-speed, reliable packet forwarding. Each component operates in its optimal environment, achieving both flexibility and reliability at the appropriate locations.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A server may receive an authentication packet from a Forwarder via a data channel. Where, the server enables a BRAS control plane function and the Forwarder enables a BRAS forwarding plane function. The server authenticates the authentication packet. When the authentication is successful, a session entry for instructing the Forwarder to forward a data packet is created, and the session entry and an identity of the data channel are transmitted to the Forwarder through a protocol connection paired with the data channel.