SoftRouter Protocol Failovers for Control Plane Separation
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Solution Overview
Problem
Traditional router architectures are overly complex due to the integration of control and forwarding functions, leading to operational complexity, sub-optimal performance, and network instability, especially when introducing new features, which often requires upgrades across multiple routers.
Innovation Solution
The SoftRouter architecture separates control and forwarding functions, implementing control plane operations on distinct entities that are not co-located with forwarding engines, using a dynamic binding protocol for flexible control and protocol failovers to manage routing and packet forwarding independently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If control and forwarding functions are integrated in traditional router architectures, then routing control and packet forwarding can be performed within a single device, but operational complexity increases and network stability deteriorates due to multiple points of control and shared failures
Solution Approach 1:
The patent segments the router into two independent components: forwarding elements (FEs) that perform packet forwarding, and control elements (CEs) that perform control plane functions. This segmentation allows independent management and failure isolation, reducing operational complexity while maintaining routing control capabilities.
Solution Approach 2:
The control plane functions are extracted from the forwarding elements and placed in separate control elements. This extraction eliminates the shared failure mode where a single router failure could affect both forwarding and control, thereby improving network stability while simplifying operational management.
2Reliability
If control processors are co-located with line cards in traditional routers, then control and forwarding can operate within the same physical device, but failure of co-located controllers causes line cards to become unmanageable
Solution Approach 1:
The control plane is extracted from the forwarding element, allowing the forwarding element to continue operating even when a control element fails. The dynamic binding mechanism ensures that a failed control element can be replaced without affecting the forwarding element's operation, thereby improving reliability.
Solution Approach 2:
The patent implements dynamic binding between forwarding elements and control elements, allowing the association to change based on operational status. When a control element fails, the forwarding element can dynamically rebind to a different control element, ensuring continuous manageability and improving failure recovery.
3Adaptability or versatility
If new routing features are added to traditional routers, then routing functionality is enhanced, but upgrades become complex and error-prone across multiple routers
Solution Approach 1:
The control elements are designed as universal, standardized components that can perform multiple control plane functions. This universality allows new routing features to be implemented by updating control elements without requiring changes to forwarding elements, significantly reducing upgrade complexity across the network.
Solution Approach 2:
By segmenting control functions into independent control elements, the patent allows features to be added or updated in isolated units. This segmentation enables targeted upgrades of specific control elements without requiring network-wide router upgrades, reducing complexity and error potential.
4Productivity
If multiple autonomous routers operate independently, then network distributed control is achieved, but uncoordinated actions lead to sub-optimal performance and network instability
Solution Approach 1:
The patent merges control plane functions across multiple forwarding elements into centralized or distributed control elements that operate in coordination. This merging allows for network-wide view and coordinated decision-making, improving both performance optimization and network stability while maintaining distributed architecture benefits.
Data Source
AI summary
The SoftRouter architecture separates the implementation of control plane functions from packet forwarding functions. In this architecture, all control plane functions are implemented on general purpose servers called the control elements (CEs) that may be multiple hops away from the forwarding elements (FEs). A network element (NE) or a router is formed using dynamic binding between the CEs and the FEs. There is a protocol failover mechanism for handling failovers initiated by FEs to transfer control from one CE to another CE.