Precision Time Protocol Profile for Data Center Applications & Related Network Requirements

Summary

The talk introduces the PTP (Precision Time Protocol) profile for data centers, aimed at improving time synchronization services. Michelle and Thomas from OCP TAB discuss the profile's development, its objectives, and its applications in enhancing distributed databases, network monitoring, and 5G synchronization. They also cover hardware advancements in time synchronization and the profile's technical specifications.

Takeaways

• 😀 The presentation discusses the PTP (Precision Time Protocol) profile, which is a set of standards and options tailored for data centers.
• 🔍 Michelle from Mera and Thomas from Nvidia led the effort in developing the PTP profile for data centers, working with many others in the community.
• 📈 The PTP profile aims to define how to integrate various time synchronization technologies to improve data center applications.
• 🕒 The core objective of the PTP profile is to enhance time synchronization service in data centers, moving from millisecond precision to microsecond precision with high reliability.
• 📚 The PTP profile document, developed within the OCP TAB, explains various options and requirements for implementing PTP in data centers, including network topology, time error performance, and clock types.
• 🔄 The profile addresses applications like distributed database systems, network monitoring, and 5G synchronization, aiming to increase transaction throughput and provide reliable air interface synchronization.
• 🌐 The PTP profile specifies the use of hardware timestamping to achieve sub-10 nanosecond accuracy and resolution, moving away from the earlier software timestamping approach.
• 🔄 The profile includes a reference model that decomposes the problem into three layers: time reference, network fabric, and server layers, each with specific roles in time synchronization.
• 🔄 The profile defines a time error requirement of plus or minus five microseconds between any two servers within a data center, ensuring high precision in time synchronization.
• 🔄 The PTP profile for data centers initially uses a model with only transparent clocks, but future work will explore a model with boundary clocks for more flexibility.

Q & A

What is the primary purpose of the PTP profile?

The primary purpose of the PTP (Precision Time Protocol) profile is to define a set of standards and options that can be tailored to meet the needs of data centers, improving time synchronization services and enabling new applications.

Who were the key contributors to the PTP profile for data centers?

Michelle from Mera and Thomas from Nvidia were the leading figures in the development of the PTP profile for data centers, along with contributions from other people and companies.

What is the main objective of the OCP TAB in relation to time synchronization?

The main objective of the OCP TAB (Open Compute Project Technical Advisory Board) in relation to time synchronization is to define a high-level time synchronization service across data center infrastructure, aiming to improve current applications or enable new ones.

What performance improvement is targeted by the PTP profile in data centers?

The PTP profile aims to provide two to three orders of magnitude better performance in time synchronization compared to current network timing protocols used in data centers, moving from milliseconds to microseconds precision with high reliability.

What are some applications that have been discussed within the PTP project group?

Applications discussed within the PTP project group include distributed database systems, network monitoring, and 5G synchronization. These applications aim to increase transaction throughput, measure network events more precisely, and provide reliable air interface synchronization.

How does the PTP profile help in maintaining the order of transactions in distributed systems?

The PTP profile helps in maintaining the order of transactions by ensuring that any committed timestamp is always in the past relative to a reference block, minimizing clock skew and thus improving the performance of distributed systems.

What is the significance of hardware timestamping in PTP implementations?

Hardware timestamping is significant in PTP implementations as it allows for more accurate time stamping closer to the hardware layer, reducing the impact of system noise, latency, and other factors associated with software timestamping. This leads to better accuracy and resolution in time synchronization.

What are the two models planned for the data center profile in PTP?

The two models planned for the data center profile in PTP are Model 1, which uses only transparent clocks and relies on network routing for failure recovery, and Model 2, which uses boundary clocks with each switch device running a boundary clock for processing messages hop by hop.

What is the time error requirement defined in the PTP profile for data centers?

The time error requirement defined in the PTP profile for data centers is that the difference between any two servers' PTP clocks within a data center should be within plus or minus five microseconds.

What is the call to action for the PTP profile development in data centers?

The call to action is to invite people to join the work stream number two to develop the second version of the profile, focusing on the use of boundary clocks, security aspects such as authentication and verification of PTP messages, and load balancing of the PTP unicast sessions.