[WT-support] WT experiences at ZL8X

[Peter Stuge]

Christian Janssen wrote:
> > If log SYNC is enabled, all QSO updates/edits should almost immediately
> > propagate to every log in the network if using default networking
> > options and every computer is using the same broadcast address.  Make
> > sure Options | Disable Log Synchronization on Network is /not/ checked
> > on any computer.  An unreliable wireless network could also cause
> > problems, perhaps due to lack of retries as well?
> 
> It does definitely not. Or I don't know how many weeks the computers 
> have to be in the network to get all synchronized. After 18 days there 
> was a different count on each computer. Maybe the log gets too big for 
> synch?

When UDP is being used it is not possible to rely on any packet ever
arriving anywhere.

UDP is inherent unreliable communication, only really suited for real
time streaming information. I e.g. used it for GPS data recently.

It is not possible to use UDP as reliable transport without first
(manually!) constructing a protocol that provides this reliability.
This means re-inventing a bit of TCP, or maybe using SCTP instead of
UDP. OpenVPN e.g. creates a reliable transport over UDP.

The network doesn't have to be unreliable or wireless to cause a UDP
packet to be dropped, UDP can be dropped anytime anywhere. Delivery
is always strictly best effort.

Of course it works most of the time, but bad network cards, bad
network cables, high packet per second load, or any other stress
factor can easily cause packets to be lost, and this is by design,
so unprocessed UDP may not be the best choice for a message bus that
needs to be reliable.


//Peter