IPC using UDP multicast

[anda_skoa]

The maximum packet size of IP is 65535 (16bit length field).

Ethernet often has 1500 byte MTU (maximum transfer unit), other technologies have smaller or larger sizes.

Since an IP packet can cross a lot of channels with different size requirements, a single IP packet might be split and reassembled quite a lot along its route.

If, for whatever reason, part of a UDP packet is lost, it can no longer be reassembled by the receiving IP stack and will be discarded.

Since UDP has not retransmit or assumption that packets will arrive this is generally OK, the transmission partners have to deal with packet loss anyway.

The larger a packet is, the higher the chance that it gets fragmented and the more fragments, the higher the chance that one is lost.

The latter chance of course depends a lot on the transmission path.
E.g. in a local ethernet this is not likely to happen at all.

Cheers,
_

[MrGentleman]

Thank you very much for your input!
Since the IPC mechanism is used only locally on the host machine and the number of bytes to send/receive are less than 200 I will implement
a publisher/subscriber system based on UDP multicast.

Best regards,
michael

[anda_skoa]

On the loopback device there shouldn't be any problem with packet loss (aside from receiver buffers running full), reordering or packet fragmentation

Cheers,
_