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-rw-r--r--Documentation/networking/ip-sysctl.txt37
1 files changed, 26 insertions, 11 deletions
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 8be76235fe67..4e9c6d7b4efc 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -311,9 +311,12 @@ tcp_no_metrics_save - BOOLEAN
311 connections. 311 connections.
312 312
313tcp_orphan_retries - INTEGER 313tcp_orphan_retries - INTEGER
314 How may times to retry before killing TCP connection, closed 314 This value influences the timeout of a locally closed TCP connection,
315 by our side. Default value 7 corresponds to ~50sec-16min 315 when RTO retransmissions remain unacknowledged.
316 depending on RTO. If you machine is loaded WEB server, 316 See tcp_retries2 for more details.
317
318 The default value is 7.
319 If your machine is a loaded WEB server,
317 you should think about lowering this value, such sockets 320 you should think about lowering this value, such sockets
318 may consume significant resources. Cf. tcp_max_orphans. 321 may consume significant resources. Cf. tcp_max_orphans.
319 322
@@ -327,16 +330,28 @@ tcp_retrans_collapse - BOOLEAN
327 certain TCP stacks. 330 certain TCP stacks.
328 331
329tcp_retries1 - INTEGER 332tcp_retries1 - INTEGER
330 How many times to retry before deciding that something is wrong 333 This value influences the time, after which TCP decides, that
331 and it is necessary to report this suspicion to network layer. 334 something is wrong due to unacknowledged RTO retransmissions,
332 Minimal RFC value is 3, it is default, which corresponds 335 and reports this suspicion to the network layer.
333 to ~3sec-8min depending on RTO. 336 See tcp_retries2 for more details.
337
338 RFC 1122 recommends at least 3 retransmissions, which is the
339 default.
334 340
335tcp_retries2 - INTEGER 341tcp_retries2 - INTEGER
336 How may times to retry before killing alive TCP connection. 342 This value influences the timeout of an alive TCP connection,
337 RFC1122 says that the limit should be longer than 100 sec. 343 when RTO retransmissions remain unacknowledged.
338 It is too small number. Default value 15 corresponds to ~13-30min 344 Given a value of N, a hypothetical TCP connection following
339 depending on RTO. 345 exponential backoff with an initial RTO of TCP_RTO_MIN would
346 retransmit N times before killing the connection at the (N+1)th RTO.
347
348 The default value of 15 yields a hypothetical timeout of 924.6
349 seconds and is a lower bound for the effective timeout.
350 TCP will effectively time out at the first RTO which exceeds the
351 hypothetical timeout.
352
353 RFC 1122 recommends at least 100 seconds for the timeout,
354 which corresponds to a value of at least 8.
340 355
341tcp_rfc1337 - BOOLEAN 356tcp_rfc1337 - BOOLEAN
342 If set, the TCP stack behaves conforming to RFC1337. If unset, 357 If set, the TCP stack behaves conforming to RFC1337. If unset,