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Sun, 16 Mar 2025 07:12:44 GMT (envelope-from bugzilla-noreply@freebsd.org) X-Authentication-Warning: kenobi.freebsd.org: www set sender to bugzilla-noreply@freebsd.org using -f From: bugzilla-noreply@freebsd.org To: net@FreeBSD.org Subject: [Bug 285158] TCP sending segment with 0 length upon receiving partial ack Date: Sun, 16 Mar 2025 07:12:43 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: Unspecified X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Many People X-Bugzilla-Who: rscheff@freebsd.org X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: net@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: cc Message-ID: In-Reply-To: References: Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="UTF-8" X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated List-Id: Networking and TCP/IP with FreeBSD List-Archive: https://lists.freebsd.org/archives/freebsd-net List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-net@FreeBSD.org MIME-Version: 1.0 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D285158 Richard Scheffenegger changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |rscheff@freebsd.org --- Comment #2 from Richard Scheffenegger --- The FreeBSD stack frequently sends empty ACK at the tail end of the send Q (bascially whenever it could be sending new data, if data were available). As Cheng pointed out, this can help keep some state fresh ( idle window), or help elicit a retransmission from the other side, when one of the final pac= kets from a non-RACK stack was discarded and these empty ACKs serve as dupacks.= =20 This is not only in PRR but other phases as well, when you look closely into the behavior of the FreeBSD stack. Do you have evidence of this behavior being detrimental to anything? --=20 You are receiving this mail because: You are the assignee for the bug.=