[Opensim-users] A theoretical question ... about communication guarantees between objects in LSL

[Slavin, Simon]

On 12 Nov 2012, at 1:57pm, Dr Ramesh Ramloll wrote:

> I was wondering if I could get some ideas from the technical wonks out there. Here's my problem (not the real one..but I simplified it a bit to keep things brief). Everything implemented in LSL of course. I have two objects A and B, A sends messages to B.  I found that there are no guarantees that B will ALWAYS receive a message sent by A. I would expect the messages to be queued up, but seems that there is a black hole somewhere. Anyway, so, I then need to think about 'Acknowledgement system' that would cause A to resend if B does not receive it (within a set waiting period...). So this means that I need to put A in a sending loop until B sends an acknowledgment back to A.
> OR.. I could just send messages from A to B, twice every time... just to reduce changes of a message not received. Should I go for the easy way ... or is there really a bigger advantage for trying to implement guarantees in.  Your thoughts?

B keeps a count of how many messages it has received.  It provides a way of asking for its current count.

A asks B for its count.  A sends its message and waits a second.  A asks B for its count again.  If the two counts match, the message was not received.

Simon.