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Date: Sun, 30 Apr 2017 00:50:22 +0000 From: bugzilla-dae...@bugzilla.kernel.org To: step...@networkplumber.org Subject: [Bug 195617] New: TCP may send small segments limited to initial window size https://bugzilla.kernel.org/show_bug.cgi?id=195617 Bug ID: 195617 Summary: TCP may send small segments limited to initial window size Product: Networking Version: 2.5 Kernel Version: 4.9.24 Hardware: All OS: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: IPV4 Assignee: step...@networkplumber.org Reporter: ambr...@gmail.com Regression: No Created attachment 256141 --> https://bugzilla.kernel.org/attachment.cgi?id=256141&action=edit packet trace I am seeing what I believe is faulty behavior when a Linux client connects to a TCP/IPv4 server which advertises a very small initial window. After the client sends a small segment limited to this small window, the server ACKs the data and extends the window considerably, but the client proceeds to send very small segments. Here is a summary of the packets: - Client: SYN - Server: SYN,ACK,Win=1 - Client: ACK - Client: ACK,Data=1B - Server: ACK,Win=49984 - Client: ACK,Data=47B - Client: ACK,Data=48B - Client: ACK,Data=48B - Client: ACK,Data=48B ... This example was with initially advertised window (WIN) equal to 1, but generally it appears that Linux will limit outgoing segments to no more than max(48,WIN). I have tested the server with a Windows 10 client which does not have this problem, the client starts sending fully sized segments when the window is extended. -- You are receiving this mail because: You are the assignee for the bug.
