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diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 32c2e9da5f3a..71c7bea97160 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -180,13 +180,20 @@ tcp_fin_timeout - INTEGER
 	to live longer.	Cf. tcp_max_orphans.
 
 tcp_frto - INTEGER
-	Enables F-RTO, an enhanced recovery algorithm for TCP retransmission
+	Enables Forward RTO-Recovery (F-RTO) defined in RFC4138.
+	F-RTO is an enhanced recovery algorithm for TCP retransmission
 	timeouts.  It is particularly beneficial in wireless environments
 	where packet loss is typically due to random radio interference
-	rather than intermediate router congestion. If set to 1, basic
-	version is enabled. 2 enables SACK enhanced F-RTO, which is
-	EXPERIMENTAL. The basic version can be used also when SACK is
-	enabled for a flow through tcp_sack sysctl.
+	rather than intermediate router congestion.  F-RTO is sender-side
+	only modification.  Therefore it does not require any support from
+	the peer, but in a typical case, however, where wireless link is
+	the local access link and most of the data flows downlink, the
+	faraway servers should have F-RTO enabled to take advantage of it.
+	If set to 1, basic version is enabled.  2 enables SACK enhanced
+	F-RTO if flow uses SACK.  The basic version can be used also when
+	SACK is in use though scenario(s) with it exists where F-RTO
+	interacts badly with the packet counting of the SACK enabled TCP
+	flow.
 
 tcp_frto_response - INTEGER
 	When F-RTO has detected that a TCP retransmission timeout was
@@ -286,7 +293,7 @@ tcp_no_metrics_save - BOOLEAN
 	when the connection closes, so that connections established in the
 	near future can use these to set initial conditions.  Usually, this
 	increases overall performance, but may sometimes cause performance
-	degredation.  If set, TCP will not cache metrics on closing
+	degradation.  If set, TCP will not cache metrics on closing
 	connections.
 
 tcp_orphan_retries - INTEGER
@@ -439,6 +446,33 @@ tcp_dma_copybreak - INTEGER
 	and CONFIG_NET_DMA is enabled.
 	Default: 4096
 
+UDP variables:
+
+udp_mem - vector of 3 INTEGERs: min, pressure, max
+	Number of pages allowed for queueing by all UDP sockets.
+
+	min: Below this number of pages UDP is not bothered about its
+	memory appetite. When amount of memory allocated by UDP exceeds
+	this number, UDP starts to moderate memory usage.
+
+	pressure: This value was introduced to follow format of tcp_mem.
+
+	max: Number of pages allowed for queueing by all UDP sockets.
+
+	Default is calculated at boot time from amount of available memory.
+
+udp_rmem_min - INTEGER
+	Minimal size of receive buffer used by UDP sockets in moderation.
+	Each UDP socket is able to use the size for receiving data, even if
+	total pages of UDP sockets exceed udp_mem pressure. The unit is byte.
+	Default: 4096
+
+udp_wmem_min - INTEGER
+	Minimal size of send buffer used by UDP sockets in moderation.
+	Each UDP socket is able to use the size for sending data, even if
+	total pages of UDP sockets exceed udp_mem pressure. The unit is byte.
+	Default: 4096
+
 CIPSOv4 Variables:
 
 cipso_cache_enable - BOOLEAN
@@ -514,8 +548,9 @@ icmp_echo_ignore_broadcasts - BOOLEAN
 icmp_ratelimit - INTEGER
 	Limit the maximal rates for sending ICMP packets whose type matches
 	icmp_ratemask (see below) to specific targets.
-	0 to disable any limiting, otherwise the maximal rate in jiffies(1)
-	Default: 100
+	0 to disable any limiting,
+	otherwise the minimal space between responses in milliseconds.
+	Default: 1000
 
 icmp_ratemask - INTEGER
 	Mask made of ICMP types for which rates are being limited.
@@ -993,8 +1028,9 @@ max_addresses - INTEGER
 icmp/*:
 ratelimit - INTEGER
 	Limit the maximal rates for sending ICMPv6 packets.
-	0 to disable any limiting, otherwise the maximal rate in jiffies(1)
-	Default: 100
+	0 to disable any limiting,
+	otherwise the minimal space between responses in milliseconds.
+	Default: 1000
 
 
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