4 ms·
I won't judge whether the heartbeat feature itself is reasonable or not. But the inclusion of a payload was unnecessary, and specifying that it has to be copied
by gpvos 13y ago
I won't judge whether the heartbeat feature itself is reasonable or not. But the inclusion of a payload was unnecessary, and specifying that it has to be copied to the reply message is so useless as to defy description. "Flexibility" my ass. It's downright suspicious.
- 0x0 13y agoNot much more suspicious than ping(8)
- kevingadd 13y agoI always assumed ping's payload was for detecting packet fragmentation/size limit issues and as a trivial mechanism for spotting things like packet corruption.
- Jare 13y agoThe payload is meant to let you distinguish responses to different Heartbeats, right? I'm no expert, but sounds reasonable enough. I could see a lower limit on max payload size, but could you please elaborate a more detailed explanation why it's unnecessary and useless?
- kevingadd 13y agoWhy would you need to send multiple different heartbeats over one connection? It's for keeping the connection alive.
- pwg 13y agoIf you are using data-grams (i.e., UDP) you have no guarantees of ordering or delivery, so you have no way to determine which transmission the echo reply you just received corresponds to without a payload that is returned to you. Now, a 64kbyte payload, that's unnecessary for simply making each packet unique. That size was likely chosen to allow for the path MTU discovery aspects. One could argue, however, that "keepalive" and "path MTU discovery" should not have been commingled, but they were.
- click170 13y agoPing manages the same thing by incrementing an integer. For example.
- tptacek 13y agoNo, ICMP echo request packets have variable-length payloads, which the receiver copies into the echo response.
- gpvos 13y agoOkay, that explains things a bit. Could be done with a fixed-size payload though. Also I understand that the flexible size is intended to help with MTU discovery, but I think that would be a separate thing from a heartbeat.