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Commit 9ae9be64 authored by Maciej Lipinski's avatar Maciej Lipinski
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IPSCS2012-special: final verision (hopefull) which includes Rodney comments

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documents/ISPCS2012-specialSession_submision/wrspec.tex
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\section {Title:} High accuracy extension/option/profile
\section {Author:} Maciej Lipinski
\section {Affiliation:} CERN -- European Organization for Nuclear Research / Warsaw University of Technology
\section {Date of submission:} 21 May 2012
\section {Date of submission:} 23 July 2012
\section {Clauses of IEEE 1588-2008 (V2) proposed for revision:}
\begin{itemize*}
\item Changes required in clauses: 7.6.2.5, 14.1.1, Annex F.4 and Annex J
......@@ -96,7 +96,7 @@
\section {Character of the proposed revision:}
New feature. This revision proposes extending PTPv2 to enable a high accuracy of synchronization --
the sub-nanosecond level of accuracy is beyond what is achievable by the current "standard" implementations.
the sub-nanosecond level of accuracy that is beyond what is achievable by the current implementations.
\section {Reason or rational for the proposed revision}
......@@ -104,28 +104,30 @@ It has been shown \cite{WRinGS}\cite{WRinISPCS2011} that PTPv2 can be implemente
a sub-nanosecond accuracy and picoseconds jitter of synchronization can be achieved over a number of
boundary clocks and several kilometers of cables. Such an implementation benefits from additional mechanisms
(i.e. Synchronous Ethernet \cite{SynchE}, phase detection \cite{icalepcs09}) incorporated into PTPv2 in
a way that keeps interoperability with "standard" implementations while improving greatly the performance.
a way that keeps interoperability with current implementations while improving greatly the performance.
The mechanisms used could be incorporated into the IEEE 1588 standard to indicate to the vendors the optional means to enhance
PTP's performance and to ensure interoperability of such high-accuracy implementations.
The presented solution is based on \cite{WRPTP}
The presented solution is based on \cite{WRPTP}.
% , the author sees a potential for the solution's
% further simplification/alignment with PTP in the process of standardization.
\section {Proposed revision:}
%loads of text here
In this section four types of changes are proposed: \\
section~\ref{syncEandEthernet} -- addition/modification of the transport annex;\\
section~\ref{highAccuracy} -- addition of an optional "high accuracy" clause; \\
section~\ref{HAprofile} -- addition of the "Default High Accuracy" profile to Annex J ; \\
section~\ref{PTPchanges} -- minor changes to the existing clauses to accommodate (1)-(3).
\subsection{Syntonization capability of IEEE 802.3/Ethernet (modification to Annex F.4)}
In this section four types of changes are proposed:
\begin{enumerate*}
\item Section~\ref{syncEandEthernet} -- addition/modification of the transport annex;
\item Section~\ref{highAccuracy} -- addition of an optional "high accuracy" clause;
\item Section~\ref{HAprofile} -- addition of the "Default High Accuracy" profile to Annex J ;
\item Section~\ref{PTPchanges} -- minor changes to the existing clauses to accommodate (1)-(3).
\end{enumerate*}
\subsection{Syntonization capability of IEEE 802.3/Ethernet (modification of Annex F.4)}
\label{syncEandEthernet}
It is proposed to extend Annex F (it is also possible to add a new annex) such that the physical syntonization
of clocks is foreseen (i.e. by using Synchronous Ethernet). Proposed changes to Table F.2 and the addition of
a new Table F.3 are presented below.
%\vspace*{-1em}
\begin{table}[ht!]
\caption{\textcolor{gray}{Table F.2 -- Ethernet transportSpecific field} (Changes to existing Table F.2)}
\centering
......@@ -138,7 +140,7 @@ ETHERNET\_SYNCE&2-6 & Ethernet $+$ Synchronous Ethernet, further specified in
\end{tabular}
\label{tab:transportSpecific}
\end{table}
% \vspace*{-2em}
%\vspace*{-2em}
\begin{table}[ht!]
\caption{Table F.3 - Syntonization capable Ethernet transportSpecific values (new table)}
\centering
......@@ -155,15 +157,15 @@ ETHERNET\_SYNCE&2-6 & Ethernet $+$ Synchronous Ethernet, further specified in
\end{table}
When frequency loopback is enabled, a port (acting as a slave) which recovers frequency from the incoming data stream
shall, after proper phase alignment, encode such frequency into the outgoing data stream and send it back to the source
shall, after proper phase alignment, encodes such frequency into the outgoing data stream and send it back to the source
(a port acting as a master).
\subsection{High Accuracy (optional) clause (addition to Annex J)}
\subsection{High Accuracy (optional) clause}
\label{highAccuracy}
It is proposed to add an optional clause that could be implemented by devices for high accuracy synchronization.
The actions which are defined in this clause take place while a PTP link is being established; that is in the
UNCALIBRATED state of the BMC-selected slave port and in the MASTER state of BMC-selected master port.
UNCALIBRATED state of the BMC-selected slave port and in the MASTER state of the BMC-selected master port.
This clause presents the following requirements to the hardware/implementation:
\begin{itemize*}
\item It shall feature constant rx/tx latencies during operation and inform higher layers
......@@ -177,23 +179,25 @@ This clause presents the following requirements to the hardware/implementation:
(e.g. using Link Delay Model, tx/rx latencies and relative delay coefficient as explained in \cite{WRPTP}).
\end{itemize*}
\vspace{-0.2cm}
\subsubsection{Definition of Data Set Fields}
The implementation-specific Data Set fields are defined to store per-port clause specific data:
(1)~values of hardware characteristics (e.g.: rx/tx latencies);
(2)~configuration parameters (e.g.: whether a calibration pattern is required, calibration period/pattern);
(3)~current state of the Finite State Machine (section~\ref{fsm}).
(3)~current state of the High Accuracy State Machine (section~\ref{fsm}).
The (re-)initialization methods and values are defined.
\vspace{-0.2cm}
\subsubsection{Definition TLVs}
It is proposed to define TLVs recognized by tlvType HIGH\_ACCURACY\_OPTION
(extension to clause 14.1.1) of the format presented in Table~\ref{tab:TLVformat}. Different messages of such TLV type
are recognized by messageID as defined in Table~\ref{tab:MessageId}. These TLVs are used to
exchange clause-specific data and trigger transitions in the Finite State Machine (section~\ref{fsm}).
exchange clause-specific data and trigger transitions in the High Accuracy State Machine (section~\ref{fsm}).
They are carried in Signaling Messages or suffixed to an Announce message (see Table~\ref{tab:MessageId}).
\vspace*{-1.0em}
\begin{table}[h!]
\caption{HIGH\_ACCURACY\_OPTION TLV format}
......@@ -212,7 +216,7 @@ They are carried in Signaling Messages or suffixed to an Announce message (see T
\end{tabular}
\label{tab:TLVformat}
\end{table}
\vspace*{-1em}
\vspace*{-2em}
\begin{table}[tbp]
\caption{Message ID values/types}
\centering
......@@ -231,19 +235,20 @@ ANN\_SUFIX & 0x2000 & Announce \\ \hline
\subsubsection{Finite State Machine}
\subsubsection{High Accuracy State Machine}
\label{fsm}
The Finite State Machine (FSM) controls the process of establishing a high accuracy (abbreviated \textit{HA}
The High Accuracy State Machine (HASM) controls the process of establishing a high accuracy (abbreviated \textit{HA}
in the figures)
link between two ports implementing high accuracy option. The FSM shall be non-preemptive with regard
link between two ports implementing high accuracy option. The HASM shall be non-preemptive with regard
to the execution of the PTP State Machine. It enables syntonization over the physical layer,
optional measurement of tx/rx latencies and exchange of their values across the link. The FSM shall be
optional measurement of tx/rx latencies and exchange of their values across the link. The HASM shall be
executed in the PTP UNCALIBRATED state on the port on which the recommended (by BMC) state is SLAVE --
called Slave -- and in the PTP MASTER state on the port which the recommended state is MASTER -- called
Master. The FSM is depicted in Figure~\ref{fig:wrFSM} and described in Table~\ref{tab:wrFSMdesc}.
The FSM shall be started when a port in non-Slave state is recommended (by BMC) to be Slave and
appropriate conditions are fulfilled (i.e. both communicating ports implement the high accuracy option).
called Slave -- and in the PTP MASTER state on the port on which the recommended state is MASTER -- called
Master. The HASM is depicted in Figure~\ref{fig:wrFSM} and described in Table~\ref{tab:wrFSMdesc}.
The HASM shall be started when a port in non-Slave state is recommended (by BMC) to be Slave and
appropriate conditions are fulfilled (e.g. both communicating ports implement the high accuracy option)
-- D\_HA\_SETUP\_REQ transition event is triggers.
% \vspace*{-1.0em}
\begin{table}[hp!]
\caption{State definitions}
......@@ -253,7 +258,7 @@ appropriate conditions are fulfilled (i.e. both communicating ports implement th
%& \\
\hline
\small
IDLE & The FSM shall be in the IDLE state while establishing of High Accuracy link is not being performed.
IDLE & The HASM shall be in the IDLE state while establishing of High Accuracy link is not being performed.
\\ \hline
PRESENT & Slave-only state. Upon entering this state, the Slave sends a SLAVE\_PRESENT
message to the Master and waits for the $LOCK$ message.\\ \hline
......@@ -281,7 +286,7 @@ RESP\_CALIB\_REQ & The Port's action in this state depends on the content of
HA\_LINK\_ON & Upon entering this state, the Master sends the HIGH\_ACCURACY\_LINK\_ON message.
In this state, the values of the clause-defined Data Set fields are set.
The \textit{IDLE} state is entered unconditionally.
The execution of the FSM is considered to be completed successfully. \\ \hline
The execution of the HASM is considered to be completed successfully. \\ \hline
\end{tabular}
\label{tab:wrFSMdesc}
\end{table}
......@@ -290,8 +295,8 @@ HA\_LINK\_ON & Upon entering this state, the Master sends the HIGH\_ACCUR
\begin{figure}[ht!]
\centering
% \vspace{-1.3cm}
\includegraphics[width=.70\textwidth]{fig/wrFSM.eps}
\caption{Finite State Machine}
\includegraphics[width=.8\textwidth]{fig/wrFSM.eps}
\caption{High Accuracy State Machine}
\label{fig:wrFSM}
\end{figure}
......@@ -303,10 +308,10 @@ The implementation of two PTP State Machine transition events described as \text
The \textbf{SYNCHRONIZATION\_FAULT} shall occur when syntonization break is detected by hardware
(e.g. link disconnected) or the high accuracy mode is exited out of another reason (e.g. management). It shall result in
clearing the record of foreign masters. The \textbf{MASTER\_CLOCK\_SELECTED} shall occur on the successful
completion of the FSM execution on the port selected by BMC as Slave and
completion of the HASM execution on the port selected by BMC as Slave and
being in PTP\_UNCALIBRATED state. Consequently, the PTP\_SLAVE state shall be entered.
\subsection{High Accuracy Default Profile}
\subsection{High Accuracy Default Profile (addition to Annex J)}
\label{HAprofile}
The delay request-response mechanism shall be the only path delay measurement mechanism for this profile.
......@@ -334,7 +339,7 @@ with DEFAULT transport Specific field, the "High Accuracy" option shall be disab
\multicolumn{2}{l}{ \textbf{Possibly helpful changes:}} \\
Clause 3.1: & Add time definition (time = time of day and/or frequency) \\
Clause 5.3.3: & Add picoseconds to the Timestamp structure \\
Clause 7.5.3: & Add High Accuracy FSM as an example in the NOTE \\
Clause 7.5.3: & Add High Accuracy State Machine as an example in the NOTE \\
% Clause 8.2.5.1 & Add portMode field to portDS (Master-only/Slave-only/Master-and-Slave \\
% Clause 9.3.2 & Modify default BMC in such way that port with portMode=Slave-only will not enter Slave
% state and the functioning of Boundary Clock (other ports) is not broken. Similarly
......
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