[tptacek]

I agree that there are circumstances where you need application-layer acks, SMTP being a canonical example.

However, there are other cases where you don't need lock-step app-layer acknowledgements; for instance, if your messages are idempotent.

I'm really just reacting to the forensic work in this article, which suggests (maybe I'm misreading) a problem that TCP doesn't actually have.

[oesmith]

Yes, if all you want is to confirm that a TCP connection has closed and flushed correctly, then AFAIK, that's entirely possible with a [shutdown, select, read] sequence.

I struggle to understand why an RPC system (as detailed in the article) wouldn't want an app-level acknowledgement though...