Subject: [Ntp] Minutes from the NTP/TICTOC session at IETF 105

From: "Dieter Sibold" <[email-masked]>
Date: Fri, 26 Jul 2019 18:04:24 -0400

Dear all,
below, please find the minutes from the last NTP/TICTOC session. They 
are also on the datatracker:
https://datatracker.ietf.org/doc/minutes-105-ntp/

Many thanks to Tal for taking the minutes.

Dieter

===============================
NTP Session
IETF 105 - Montreal
Monday, July 22, 2019
15:50-17:50 (UTC-04:00)
Meeting Minutes
===============================

WG chairs: Karen O'Donoghue, Dieter Sibold
Meeting minutes: Tal Mizrahi
Jabber: Rich Salz

Chair Slides
------------
Presenter: Karen O'Donoghue
Slides:
https://datatracker.ietf.org/meeting/105/materials/slides-105-ntp-ntp-wg-chair-slides-00

Summary:
- Note well was presented.
- The agenda for the current session was presented.
- Agenda bashing: nothing proposed.
- We will start with TICTOC related issues.
- After that we will go to the NTP session.
- NTP status:
   - The NTP BCP was finally published ! Thanks to Denis, Dieter and 
Harlan.
   - Three documents that are ready to proceed to the IESG: NTS, 
Guidlines for defining
     packet timestamps, and Interleaved Mode. These documents will be 
submitted to the IESG
     for publication in the next few days.
- There was a virtual hackathon this weekend. Further details to follow.

==============
TICTOC Session
==============

Summary:
- The IEEE 1588 Enterprise profile draft is ready to go the IESG.
- Working group will conclude soon.
- The following presentation is related to TICTOC.

Secure Enterprise Data Center Profile for IEEE 1588 Precision Time 
Protocol (PTP)
---------------------------------------------------------------------------------
Presenter: Doug Arnold

Presentation:
https://datatracker.ietf.org/meeting/105/materials/slides-105-ntp-secure-enterprise-data-center-profile-for-ieee-1588-precision-time-protocol-ptp-00

Draft: no draft

Summary:
- A short update about the IEEE 1588 standard revision, which is near 
publication.
- A secure profile of IEEE 1588 for enterprise and data center networks.
- Mainly for the financial industry.
- Synchronization requirements are not very stringent.
- One of the goals is to reuse key exchange mechanisms that are already 
deployed in data
   centers.

Discussion:
- Tal Mizrahi: interesting work, relevant to this working group. Have 
you considered other
   applications than financial, and other accuracy requirements?
- Doug: not at this point. The main target customer we have been hearing 
from is the
   financial industry.
- Stu Card: anything related to White Rabbit?
- Doug: White Rabbit is very interesting to high frequency trading. In 
this context we are
   talking about the regulatory compliance in financial networks, which 
is on the order of
   100 microseconds, and white rabbit is less interesting.
- Watson Ladd: you mentioned key exchange. Have you considered the NTS 
key exchange?
- Doug: we have not got to the point of choosing a specific key 
exchange. These networks
   will also run NTP, so a common key exchange may be useful.
- Stu Card: anything related to PTP over unstable links, such as 
wireless?
- Doug: not in this context. There is some work in 802.1 to support 
WiFi, but not relevant
   to this work.
- Daniel Franke: an accuracy of 100 microseconds can be achieved in NTP 
in a LAN. Why not
   use NTP?
- Doug: right, you can get this accuracy with NTP. Customer are asking 
for PTP because
   they are anticipating the future, expecting these requirements to 
become more strict.
- Daniel: you need a trusted path between the source and client. That is 
the main issue.
- Doug: hardware timestamping in NTP can get a very accurate time 
transfer. On the other
   hand customers are expecting secure PTP.
- Daniel: if it does not solve a technical problem then it may not be 
interesting to solve
   in the IETF.
- Doug: PTP is popular in a lot of industries because transparent clocks 
and boundary
   clocks are more available than edges with hardware timestamping.
- Karen: I am not sure we will resolve this.
- Kristof Teichel: I agree with Daniel that one way communication will 
always be subject
   to delay attacks regardless of cryptography. We are working on 
combining one-way and
   two-way approaches. Using a two-way approach in PTP will be useful.
- Doug: PTP usually uses a two-way approach. You have a point that the 
reference delay may
   be calibrated for a link, and then this information can be used as a 
reference for
   detecting attacks.
- Karen: the revision of IEEE 1588 called version 2.1 that will be 
published soon will
   include a security TLV, but this is just the beginning of the work on 
security. The more
   we work together on this the better.

===========
NTP Session
===========

NTP Hackathon Summary
---------------------
- There was a remote hackathon on the weekend on NTS.
- The relevant people are not available to give an update.
- A summary of the test results will be available on the meeting 
materials page:
   https://datatracker.ietf.org/meeting/105/materials/slides-105-ntp-hackathon-results-01
- We will set up a separate mailing list for implementation aspects, and 
announce it on
   the NTP mailing list.

A YANG Data Model for NTP
-------------------------
Presenter: Dhruv Dhody

Presentation:
https://datatracker.ietf.org/meeting/105/materials/slides-105-ntp-a-yang-data-model-for-ntp-00

Summary:
- The draft was updated based on comments.
- More comments will be addressed soon.
- NTS is currently not part of the YANG model. The authors suggest to 
continue this in a
   future document.

Discussion:
- Suresh Krishnan: I believe the NTS should be in the current YANG 
model. The YANG model
   does not have to wait for NTS to be published.
- Dhruv: this may hold back the document. But we need to do the right 
thing.
- Karen: we may want to separate the NTP server from the NTS 
implementation. Logically
   these are different modules.
- Suresh: but there is some commonality. We need to do the right thing.
- Dhruv: I want to know how the working group feels.
- Harlan: is there a reference implementation of the YANG model? Is it 
possible to use any
   of the existing authentication methods with this YANG model?
- Dhruv: reference impelmentation: we have something very basic, but not 
production
   quality. Regarding the authentication - the private key part is 
there. Autokey - does
   not exist. NTS - does not exist.
- Suresh: it is possible to send the draft out like this, but make sure 
we do not have to
   do a bis version of this work.
- Dhruv: it will definitely not need a bis version. It is always 
possible to add more
   content by augmentation.

Port Randomization in the Network Time Protocol Version 4
---------------------------------------------------------
Presenter: Fernando Gont (remote)

Draft:
https://www.ietf.org/archive/id/draft-gont-ntp-port-randomization-03.txt

Presentation:
https://datatracker.ietf.org/meeting/105/materials/slides-105-ntp-port-randomization-in-
the-network-time-protocol-version-4-00

Summary:
- We want to ask whether there is interest to adopt this draft in the 
WG.

Discussion:
- Karen: can you summarize the traffic on the mailing list?
- Fernando: regarding port randomization on a per-transaction basis - 
packets may go
   through different paths, and affect synchronization. Therefore the 
document chose to
   randomize on a per association basis. Another comment from Danny is 
that this does not
   address blind attacks. We argue that it addresses blind attacks in 
the transport layer,
   but it is independent of other layers, where blind attacks may be 
performed.
- Karen: any further comments about adoption?
- No answers.
- Karen: does anyone oppose?
- No answers.
- Watson: I would be willing to read it and send comments.
- Harlan: willing to review.

On Implementing Time
--------------------
Presenter: Aanchal Malhotra

Summary:
- No major changes.
- One editorial change.
- Karen: Any comments about adopting the document?
- No comments.
- Karen: we will look at adopting it.

Roughtime
---------
Presenter: Aanchal Malhotra

Summary:
- Two major changes: 1. Timestamp section: we have updated to the Julian 
date format, and
   2. how Roughtime addresses delay attacks (thanks Tal).
- Some clarifications from Marcus related to implementation.
- Karen: any questions or comments?
- No comments.
- Watson: I am a co-author. We are working on adjusting the PLL based on 
time estimates.
   Please let me know if people think this is necessary.
- Karen: we will consider adoption.

A Secure Selection and Filtering Mechanism for NTP
--------------------------------------------------
Presenter: Neta Schiff

Draft:
https://datatracker.ietf.org/doc/draft-schiff-ntp-chronos

Presentation:
https://datatracker.ietf.org/meeting/105/materials/slides-105-ntp-a-secure-selection-and-
filtering-mechanism-for-the-network-time-protocol-version-4-00

Summary:
- A short reminder about Chronos.
- A summary of the comments received, and how they were addressed.

Discussion:
- Harlan: is this appropriate for authenticated, or for un-authenticated 
time?
- Neta: we believe both.
- Harlan: how does this work with un-authenticated time?
- Neta: we assume an attacker that has powerful access to servers or to 
paths.
- Harlan: that is a stringent assumption.
- Neta: right, also delay attacks are in scope.
- Harlan: it is a pretty big assumption over a large number of servers.
- Neta: right, we are considering stringent assumption.
- Suresh: one thing I like is that the threat model is such that we 
usually assume that
   endpoints are not compromised, but this draft does not assume that. I 
like this draft.
- Danny: might be useful if tied together with an NTP server.
- Neta: Chronos is intended for the client side, allowing easier 
deployment without
   affecting existing servers. How servers can be improved is for 
further research.
- Karen: any other questions?
- Karen: Neta will be presenting this work tomorrow in IRTF open, as she 
is the winner of
   the ANRP prize this IETF meeting.

AOB
---
- We have some pending call-for-adoptions.
- The ref ID document may be ready for working group last call.
- Harlan: should be ready to go.
- Extension field drafts will also be ready for working group adoption 
soon.
- Aanchal: what about the data minimization draft?
- Karen: it went through WG last call. Waiting for some comments. We 
need to check again,
   and  but I believe it will be ready to be sent to the IESG.
- Harlan: I did not receive any responses to the comments for the data 
minimization.
- Karen: we need to review the mailing list. I thought we were waiting 
for information
   from Harlan.
- Harlan: did not know any information is missing.
- Karen: we will hold virtual interims. We may hold virtual hackathons 
for NTS.
- Karen: adjourned early. See you next IETF meeting.

Adjourned at 16:58.