doc: make the description of how tcp_ecn works more explicit and clear

Make the description of how tcp_ecn works a bit more explicit and clear.

Signed-off-by: Rick Jones <rick.jones2@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 98ac0d7552a1f0821486091a65a253f3b09b08db..c6d5fee888c4afa9ad3f9454009b55e0616979a1 100644 (file)
--- 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