Virtual Clock Domain Segmentation for Data Center Scalability
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Solution Overview
Problem
Existing precision time protocol (PTP) systems struggle to provide synchronized clocks across large and complex data center environments, where tens of thousands of servers host hundreds of thousands of virtual machines, due to limitations in clock domains and synchronization precision.
Innovation Solution
The implementation of virtual clock domains (vCDs) that map to physical clock domains, allowing virtual machines to access synchronized time values across multiple local area networks, while utilizing network interface cards (NICs) to synchronize hardware clocks and provide timestamp values securely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PTP is used to synchronize clocks in large data center environments, then clock synchronization is achieved, but the system struggles to provide precise synchronization across vast networks due to clock domain limitations
Solution Approach 1:
The patent segments the physical clock domain into multiple virtual clock domains (vCDs) by introducing a virtualization layer. Each vCD is identified by a virtual clock domain identifier (vCD ID) and can be independently managed and assigned to different virtual machines. This segmentation allows the system to scale from a single physical clock domain to millions of virtual clock domains while maintaining synchronization precision through the underlying PTP infrastructure.
Solution Approach 2:
The patent adds a virtualization dimension to the traditional clock domain architecture. By introducing virtual clock domains as an additional layer between the physical hardware and the virtual machines, the system can provide millions of logical clock domains without requiring proportional increases in physical infrastructure. This dimensional addition resolves the contradiction between precision and scalability.
2Ease of operation
If hardware clocks are made accessible to virtual machines for timestamping, then timestamping functionality is provided, but the clocks become vulnerable to unauthorized manipulation
Solution Approach 1:
The patent introduces the network interface card (NIC) as an intermediary between the hardware clocks and virtual machines. The NIC's timestamping circuitry receives and processes timestamp requests from VMs, retrieves accurate time values from the hardware clocks, and returns them to the VMs. This intermediary layer maintains ease of operation by preserving timestamping functionality while enhancing reliability by preventing direct VM access to and manipulation of the hardware clocks.
Solution Approach 2:
The patent extracts the clock access functionality from the virtual machines and relocates it to the NIC hardware. By taking out the timestamping operation from the software layer (VMs) and implementing it in the hardware layer (NIC), the system provides continued accessibility for timestamping while securing the hardware clocks from unauthorized manipulation. The NIC acts as a protected gateway that VMs can access through controlled interfaces.
3Adaptability or versatility
If multiple clock domains are supported with 256 reference clocks, then clock domain diversity is provided, but the system cannot support millions of virtual clock domains required for large data centers
Solution Approach 1:
The patent creates virtual copies of clock domain functionality through the virtualization layer. Instead of requiring millions of physical reference clocks, the system creates virtual representations (vCDs) that can be replicated and distributed across the data center infrastructure. Each vCD is a logical copy that maps to the underlying PTP infrastructure, allowing millions of instances without proportional increases in physical hardware complexity.
Solution Approach 2:
The patent makes the PTP infrastructure universal by enabling it to serve multiple functions: supporting both traditional physical clock domains and numerous virtual clock domains through the same hardware platform. The NIC and PTP infrastructure can simultaneously manage 256 physical clock domains and millions of virtual clock domains, eliminating the need for separate management systems and reducing overall device complexity.
Data Source
AI summary
Tenants in data centers may want access to high precision clocks without having to run their own PTP stacks or reference clocks. Furthermore, different tenants may want their workloads synchronized to their own secured clock domain. PTP, the currently dominant synchronization protocol, allows for only 256 clock domains (CDs). Virtual CDs (vCDs) virtualize the concept of clock domains by maintaining a hardware clock within a host computer, receiving a network clock domain packet that includes a clock domain identifier and an origin timestamp produced by a reference clock, using the network clock domain packet to synchronize the hardware clock to the reference clock, and using the hardware clock to provide a hardware timestamp value to a virtual machine (VM) running on the host computer or to a process running on the host computer, wherein the hardware clock is secured from manipulation by the VM or by the process.