[AusNOG] EVERYONE should have a Stratum 1 time server, right?

[John Edwards]

On Tue, 15 Nov 2022 at 02:48, Mark Delany <g2x at juliet.emu.st> wrote:

> On 14Nov22, John Edwards allegedly wrote:
> > best practice was to move away from using GPS for time
> > sync on mobile sites and trust Synchronous Ethernet from central sources
> > instead.
>
> Is this mainly for high-density micro-sites?
>

In this instance yes, it's a natural fit for small cells which might be
indoors.


> And by "Synchronous Ethernet" do you mean PTP?
>

Yes, I mean IEEE 1588 or ITU-T G.8261/G.8262/G.8264, usually found on
higher-end metro ethernet switches, aka PTP.

I also presume these "central sources" ultimately get traceable time from
> GPS.
>

I don't think there's anything that stops the operator using their own
nuclear clock, but yes.


> I ask because I still see cell towers being deployed today with provision
> for GPS
> equipment.
>

The Australian mobile network ecosystem has evolved differently to how the
rest of the world provides mobile networks, we have some of the most
expensive mobile networks globally, although we do get some of the best
urban coverage for those high monthly plans. SyncE networks still allow for
local GPS, at the end of the day it's about synchronisation rather than
orchestration.

GPS itself is a network of 31 moving satellites that happen to be in sync,
it's about trusting the process rather than any individual device. Pour one
out for Australia's DGPS that was turned off in 2020.

I can easily imagine that for 5G micro-sites deployed in every second
> building in a city,
>

5G mmWave doesn't even go through glass. Think: every floor in every
commercial building, assuming that an application emerges that warrants
10gbps on mobile devices.

John
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