Some more articles.
http://www.vision-systems.com/display_article/286656/19/none/none/Feat/Latency-and-determinism-in-GigE-Vision-systems

"Different protocol architectures also impact latency and determinism.
With standard Internet traffic, TCP is commonly implemented to ensure
data are not corrupted or lost during the transmission event between
devices. When the system detects corruption, it initiates a process
to re-attempt the initial event. This significantly increases the amount
of time required to complete the initial event, resulting in much higher
jitter. Since GigE Vision implements the UDP protocol, the re-attempt
process can be made optional, which keeps the jitter lower and
permits better determinism for short maximum guaranteed
response times."

If you use UDP, then there is possibility of packet loss.
In that case, a packet may take infinite time to reach
the target. So it is non-deterministic in a sense, right?
Does Hard Real-Time (deterministic) allow packet loss?
Does Soft Real-Time allow packet loss?

I know there are many applications which do not need
hard real time and allow packet loss (you just wait for
the next packet which contains the same data).

Kind of confusing...

Xiaofan
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