Hi Greg,

I went through your presentations in the TICTOC meeting. The work items
are valid. However, I would like to raise discussion of the suitable
standards group in the case of telecom profiles of PTP. My viewpoint is
a mobile network vendor's.

Security

Frequency synchronization without on-path support: 3GPP has specified
the use of IPSEC for securing mobile backhaul if necessary. PTP can use
the same IPSEC tunnels that are set up for the rest of the base station
traffic. Thus, no new security methods are needed at least considering
mobile backhaul.

In the case of time synchronization with on-path support, if
security-enabled, all PTP nodes need to authenticate their immediate
neighbors in terms of synchronization. On the other hand, the data
traffic rather needs end-to-end security, moreover with end-to-end
encryption. Therefore, probably a separate security solution is needed
for PTP. There is already an experimental annex in PTP, which covers
security for PTP in general - i.e. not only for PTP/UDP/IP stack but
also PTP/Ethernet stack. The solution has been verified by security
experts of NIST. TICTOC should not declare itself as the owner of PTP
security unless the timing community requests it.

Management

ITU-T Q13/SG15 has decided that management is out of scope of the PTP
telecom profile for the time being. Telecom vendors have incorporated
the management of packet timing into their network management systems. I
don't see that the telecom companies have done a mistake in standards
work that needs to be corrected by TICTOC. Surely it is possible to
raise the management issue again in Q13 if needed.

Conclusion

I propose that the possible security & management work carried out in
TICTOC would not concern telecom usage of PTP unless IETF and ITU decide
together to do otherwise. 

Best regards, Antti

Antti Pietilainen
Nokia Siemens Networks
Mobile transport research
Linnoitustie 6
02600 ESPOO
Finland
tel. +358-71-8036660  
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