IETF in Singapore

Sanjeev Gupta ghane0 at
Sun Nov 17 23:59:06 UTC 2019


(I am cc:ing Christer and Dieter in case they are not on this list).

Christer was telling me about some of the interesting things they are
doing, like an NTP (NTS) server using FPGA, cesium masters, etc.  I have a
single band GPS, so was trying to talk down all the cool toys he has.

On the need for the cesium masters, Christer mentioned that the
requirements for 5G were usually specified as "within 30ns".  According to
him, this is not a requirement as specced, but a vendor has this ability,
so they are pushing this as "absolutely necessary".  As Netnod's customers
may want this as well, they have to be able to provide (some sort of?) PTP
to the Telco.

Christer agreed when I suggested that this is likely to be a "within
network sync"; with respect to UTC, the network could drift.

I have sinced looked around, requirements mentioned range from 1.5us to
65ns.  It seems to depend on what services are offered, beam forming
requires sub-us, location services sub-100ns.  And few references mention
if this is RTT or delay or ...

Vendor Blog:
Ericsson on Time in RAN:

Sanjeev Gupta
+65 98551208

On Mon, Nov 18, 2019 at 6:54 AM Richard Laager via devel <devel at>

> On 11/17/19 6:44 AM, Sanjeev Gupta via devel wrote:
> > Interesting discussion on the 5G requirements
> Any chance you can even briefly expand on this? In other words, what are
> the 5G requirements that relate to NTP/NTS?
> --
> Richard
> _______________________________________________
> devel mailing list
> devel at
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