hesela.devTCP receive window
The TCP receive window is the receiver-advertised byte count it is prepared to accept starting at the acknowledgment number.
Flow control: The advertised window is not the receiver's total socket buffer size; received data awaiting application consumption and space not yet advertised also matter. A zero window invokes probing and does not by itself mean the connection has failed [1].
Encoding: Window scaling must be offered by both endpoints during the handshake. Its shift is fixed separately for each direction; window fields in SYN and SYN-ACK segments remain unscaled. The option enlarges the receive-window representation, not the sender's congestion window [2].
Relations
Limitations
- A large advertised window does not prove that the application has consumed data or that a storage write is durable. [1, 2]
Citations
- RFC 9293: Transmission Control Protocol, sections 3.1 and 3.8.6
- RFC 7323: TCP Extensions for High Performance, sections 2.2 and 2.3
Sources & caveats
- Source review, not a measured network or storage result. TCP window budgets describe one sending direction of one connection.