[time-nuts] Google NTP Servers and smearing leap seconds...
bob.paddock at gmail.com
Fri Sep 16 23:50:05 UTC 2011
On Fri, Sep 16, 2011 at 2:36 PM, Hal Murray <hmurray at megapathdsl.net> wrote:
> 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
There are some big names in Banking and Stocks behind the
Advanced Message Queuing Protocol (AMQP):
Actually Time Nut Grade measurements are not addressed at this level
to my knowledge.
<p><b>Round Trip</b>: The term round trip refers to the
process of a peer sending a command to its partner and
receiving confirmation that the command is complete. Round
trips are necessary for synchronization of world views,
however, it is not necessary for a client to wait and do
nothing while a round trip occurs or only deal with a single
round trip at a time.</p>
<p><b>Round Trip Time (RTT)</b>: The term RTT refers to the
time taken to complete a round trip. This is described with
the following formula:</p>
RTT = 2*latency_network + latency_processing
<p>Note that RTT at the execution layer differs from RTT at
the network layer. At the network layer the processing
latency is zero resulting in an RTT of twice the network
latency. At the execution layer the processing time becomes
significant if, for example, processing the command requires
sending data to disk. This would be the case with durable
messages and the RTT would then include the Broker's disk
> but I won't be surprised if they are thoroughly
There is also the even more obscure 0MQ:
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