Secure tunneling of high-precision clock synchronization protocols and other time-stamped data

This article analyzes the viability of secure tunneling for clock synchronization protocols with special respect to high-precision clock synchronization requiring hardware timestamping. It investigates whether security mechanisms introduced to protect timing information have an impact on the precision of clock synchronization. Two reference designs - one for an MII-based and one for a MAC-based time stamper - are used together with IPsec as a commonly used and favored secure tunneling protocol. Results of these investigations show that a straightforward application of the IPsec tunnel is not possible, yet there exist several possibilities to meet the requirements of secure high-precision hardware-supported clock synchronization together with IPsec, each however tied to special boundary conditions.