[time-nuts] Google NTP Servers and smearing leap seconds...

[Javier Herrero]

Should not be ms instead of us for a transatlantic cable? 60us at light 
speed is only 18km ;)

Regards,

Javier

El 16/09/2011 23:53, shalimr9 at gmail.com escribió:
> I just read they were building a new transatlantic cable that will shave 10uS from the normal 60 or so uS and that for large traders, 1uS represents 100 million $ per year saving/increased revenue.
>
> Didier KO4BB
>
> Sent from my BlackBerry Wireless thingy while I do other things...
>
> -----Original Message-----
> From: xaos at darksmile.net
> Sender: time-nuts-bounces at febo.com
> Date: Fri, 16 Sep 2011 13:05:40
> To: Discussion of precise time and frequency measurement<time-nuts at febo.com>; Hal Murray<hmurray at megapathdsl.net>
> Reply-To: Discussion of precise time and frequency measurement
> 	<time-nuts at febo.com>
> Subject: Re: [time-nuts] Google NTP Servers and smearing leap seconds...
>
> You are right.
>
> To be more precise, I should have said that the time sync should be at
> least 1 order of magnitude less. In the case of<10us turnaround time,
> it is assumed that the timesync is<1us. This is the reason that
> everyone uses multiple stratum 1 NTP servers using GPS in their
> datacenters.
>
> So the Forex transaction goes like this:
>
> 1. (Both parties) Are we in proper sync timewise?
> 2. (Party 1) I need transaction type x. My timestamp is: xxxx.xxxx. Go.
> 3. (PArty 2) Confirmed. My timestamp is: yyyy.yyyy. Go.
>
> These timestamps are legal entities and bind both parties to the transaction.
> That's why transactions have a data transfer entity in the middle
> (Reuters, Bloomberg) which guarantees proper timesync for all involved.
>
> With Reuters in the middle, only the Reuters timestamp (arrival time
> and send time) can be trusted.
>
> However, Many times you will see a Reuters machine lose sync and the
> UNIX SA's will restart NTP on it. Reuters puts more than one machine
> per site for redundancy.
>
> Quoting Hal Murray<hmurray at megapathdsl.net>:
>
>>
>> xaos at darksmile.net said:
>>> You can forget Wall St. firms and Banks for starters.
>>
>>> They need sub-microsecond accurate timing as some instruments (Forex)   are
>>> moving to<10 microsecond latency from order entry to order ack.
>>
>> 10 microsecond latency doesn't say anything about how accurate the time has
>> to be.
>>
>> Does anybody have a good URL on the accuracy requirements of banks and/or
>> stock markets?  I expect there are both legal and technical issues.  I'd like
>> to understand them separately but I won't be surprised if they are thoroughly
>> tangled.
>>
>> --
>> These are my opinions, not necessarily my employer's.  I hate spam.
>>
>>
>>
>>
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>
>
>
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