[Documentation] Please elaborate on optional reliability and order

[pachanga]

Hi!

In the Features section of the README the library is said to have "Optional reliable" and "Optional ordered" features. Could you please elaborate a bit more on these features?

Looking at the API it seems that the Send method has only "reliable" flag. Does it mean that "reliable" packets still can be received out of order?

[neyrox]

Hello @pachanga. Yes, reliable packets can be received out of order. Library controls ordering only for fragments of messages (messages that are too big to be sent in one datagram). Fragments reassembled in the correct order. Some basic ordering implemented via ReceivedSmartPacket structure. There are boolean InOrder flag. But it is meaningful only for non-fragmented messages.

[pachanga]

Thanks for clarifications!

Some basic ordering implemented via ReceivedSmartPacket structure. There are boolean InOrder flag. But it is meaningful only for non-fragmented messages.

Please correct if I'm wrong, does it mean - if the packet was: a) was sent reliably b) but fragmented c) and was received out of order - InOrder flag wouldn't reflect this?

[neyrox]

Order is a tricky question if packet was truncated, there are a lot of cases when we can't say it for sure. For example we send fragmented packet 1 (datagrams 1 and 2) and packet 2 (datagram 3 and 4), but received them in that order: (1-3-2-4). Was that in-order or not?

[pachanga]

Order is a tricky question if packet was truncated, there are a lot of cases when we can't say it for sure. For example we send fragmented packet 1 (datagrams 1 and 2) and packet 2 (datagram 3 and 4), but received them in that order: (1-3-2-4). Was that in-order or not?

Yep, that's tricky. I guess it doesn't make sense to analyze InOrder flag because it's kinda too low level information. I'll just rather introduce my own logical sequence numbers for snapshots which would allow me to understand where the received packet should be placed.