Attention is currently required from: dexter, pespin.

laforge has posted comments on this change. ( https://gerrit.osmocom.org/c/osmo-bts/+/36018?usp=email )

Change subject: pcu_sock: forward PCU_VERSION only once ......................................................................

Patch Set 1: Code-Review-1

(1 comment)

Commit Message:

https://gerrit.osmocom.org/c/osmo-bts/+/36018/comment/92061cdd_f175c317 PS1, Line 10: is not active the PCU even sends the version number in regular

I'm still not following @pmaier@sysmocom.de. […]

This entire thread and patch are bizarre. Why would the PCU send that information multiple times? We are using a connected socket, so the information cannot change ever since the socket has first connected. A connected unix domain socket cannot loose messages, so retransmissions are not useful, they just queue up and (if not processed) clog the socket buffer. So if the PCU has a bug in that regard, it shall be addressed in the PCU, rather than the BTS plastering over / hiding a PCU bug from the BSC.

I also don't understand why the PCU would do this any different than any of the other many unix domain sockets we use in osmocom, like MNCC or L1CTRL, or more recently the socket between libosmo-e1d and osmo-e1d. I'm not aware that any of the implementations of such protocols would ever re-transmit any message for reasons described above.

The only valid situation where I could imagine the PCU "re-transmitting" is when the PCU re-spawns all the time while the BTS keeps running. Then each time the PCU connects, it says "hello" and indicates its version. But then we might want to look at why it's re-spawning all the time and whether that's the intended situation.