Stacked Network Device PTP Boundary Clock Load Distribution
Solution Overview
Problem
Existing systems face challenges in configuring a stacked device as a Boundary Clock (BC) in Precision Time Protocol (PTP) networks, leading to overwhelming of upstream devices due to large PTP loads from multiple endpoints, making it infeasible to use stacked devices as BCs effectively.
Innovation Solution
Implementing an internal PTP instance within the stacked network device to synchronize clocks of individual members, allowing each device to act as a BC and share the PTP load, while presenting the stack as a single BC to the external network, thus distributing the load across multiple devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a stacked device is configured as a Boundary Clock in PTP networks, then time synchronization precision is improved, but upstream devices become overwhelmed due to large PTP loads from multiple endpoints
Solution Approach 1:
The stacked device is divided into multiple member devices, each capable of independently processing PTP packets. By distributing PTP packet processing across multiple members rather than concentrating all endpoint connections on a single member, the PTP load is segmented and distributed throughout the stack, preventing any single upstream device from being overwhelmed while maintaining precise time synchronization across the entire stacked device as a Boundary Clock
2Device complexity
If multiple members are connected to a single upstream device, then device complexity is reduced, but the upstream device becomes overwhelmed by PTP loads
Solution Approach 1:
The stacked device segments the PTP processing function across multiple member devices while maintaining a unified Boundary Clock interface to upstream devices. Each member device processes PTP packets independently, distributing the computational load. This segmentation allows the stacked device to present a simplified single-device interface to upstream devices (maintaining low configuration complexity) while internally distributing the PTP load across multiple members (preventing load concentration and device overwhelming)
Solution Approach 2:
Multiple member devices are merged into a single logical Boundary Clock entity that interfaces with upstream PTP devices. The stack appears as one unified device to upstream devices, simplifying network configuration and management. Simultaneously, the individual members retain independent PTP processing capabilities, allowing the combined structure to distribute PTP loads effectively across all members while maintaining the simplified unified interface
Data Source
AI summary
Systems, methods, and devices are described which implement an internal Precision Time Protocol (PTP) instance on a stacked network device within a larger external PTP instance in the network to which the stacked network device. The internal instance of PTP is local to the stacked network device synchronizes the N devices (“members”) in the stack. Each of the members of the stacked network device may act as a BC in this local virtual instance of PTP. One member, which may be referred to as the commander node or primary member node, may synchronize its clock based on an external GSC or external BC, and then that member may act as a BC for a downstream member, and so on in an iterative manner until all of the members within the stacked network device have synchronized clocks. The individual members may also act as BCs to the external endpoints coupled thereto, providing PTP timestamp messages to those endpoints.