[Ntp] ntpv5 requirements

[Doug Arnold <[e-mail]>]

Here are some suggestions for draft-ietf-ntp-ntpv5-requirements-01

Section 2
The current standard for PTP is IEEE 1588-2019.

Some financial institutions and data centers use ntp rather than ptp not because they don’t need accuracy or can’t deploy ptp, but because they prefer it.  The reasons that they prefer it are familiarity, and a dislike of the BMCA in ptp.  I have heard of non-default algorithm ntpv4 implementations that achieve 50 ns time transfer accuracy in specialized financial networks.

Section 3.5

Consider adding something like this sentence: “If a server implements leap second smearing, then it MUST indicate that smearing is active in the response message whenever it is active, and include all necessary information for the determination of TAI and UTC.”

Section 3.8

Consider adding something like this sentence: “The protocol SHOULD allow for different mechanism for authentication and confidentiality to support different use cases.”

For example: Judah Levine at NIST recently told me that he cannot implement NTS with his current server resources and the number of clients NIST supports.  However, when I told him about TESLA he thought a scheme based on that would be doable, as long as the keys didn’t have to change too often.