From mboxrd@z Thu Jan 1 00:00:00 1970 From: raj@tardy.usa.hp.com (Rick Jones) Subject: [PATCH net-next] doc: make the description of how tcp_ecn works more explicit and clear Date: Wed, 28 Nov 2012 11:53:10 -0800 (PST) Message-ID: <20121128195310.C438D2900459@tardy> To: , Return-path: Received: from g5t0006.atlanta.hp.com ([15.192.0.43]:27346 "EHLO g5t0006.atlanta.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754501Ab2K1TxO (ORCPT ); Wed, 28 Nov 2012 14:53:14 -0500 Sender: netdev-owner@vger.kernel.org List-ID: From: Rick Jones Make the description of how tcp_ecn works a bit more explicit and clear. Signed-off-by: Rick Jones --- diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index 98ac0d7..2992160 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -199,15 +199,16 @@ tcp_early_retrans - INTEGER Default: 2 tcp_ecn - INTEGER - Enable Explicit Congestion Notification (ECN) in TCP. ECN is only - used when both ends of the TCP flow support it. It is useful to - avoid losses due to congestion (when the bottleneck router supports - ECN). + Control use of Explicit Congestion Notification (ECN) by TCP. + ECN is used only when both ends of the TCP connection indicate + support for it. This feature is useful in avoiding losses due + to congestion by allowing supporting routers to signal + congestion before having to drop packets. Possible values are: - 0 disable ECN - 1 ECN enabled - 2 Only server-side ECN enabled. If the other end does - not support ECN, behavior is like with ECN disabled. + 0 Disable ECN. Neither initiate nor accept ECN. + 1 Always request ECN on outgoing connection attempts. + 2 Enable ECN when requested by incomming connections + but do not request ECN on outgoing connections. Default: 2 tcp_fack - BOOLEAN