spelling fixes: Documentation/

[mv-sheeva.git] / Documentation / networking / ip-sysctl.txt

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 702d1d8dd04a1261b598a0370095df1cbfc0899e..747a5d15d529c8bff449d88802b79b70a213a775 100644 (file)
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -179,11 +179,38 @@ tcp_fin_timeout - INTEGER
        because they eat maximum 1.5K of memory, but they tend
        to live longer. Cf. tcp_max_orphans.
 
-tcp_frto - BOOLEAN
-       Enables F-RTO, an enhanced recovery algorithm for TCP retransmission
+tcp_frto - INTEGER
+       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.
+       rather than intermediate router congestion.  FRTO 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 FRTO 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 FRTO
+       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
+       spurious (i.e, the timeout would have been avoided had TCP set a
+       longer retransmission timeout), TCP has several options what to do
+       next. Possible values are:
+               0 Rate halving based; a smooth and conservative response,
+                 results in halved cwnd and ssthresh after one RTT
+               1 Very conservative response; not recommended because even
+                 though being valid, it interacts poorly with the rest of
+                 Linux TCP, halves cwnd and ssthresh immediately
+               2 Aggressive response; undoes congestion control measures
+                 that are now known to be unnecessary (ignoring the
+                 possibility of a lost retransmission that would require
+                 TCP to be more cautious), cwnd and ssthresh are restored
+                 to the values prior timeout
+       Default: 0 (rate halving based)
 
 tcp_keepalive_time - INTEGER
        How often TCP sends out keepalive messages when keepalive is enabled.
@@ -266,7 +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
@@ -413,6 +440,12 @@ tcp_workaround_signed_windows - BOOLEAN
        not receive a window scaling option from them.
        Default: 0
 
+tcp_dma_copybreak - INTEGER
+       Lower limit, in bytes, of the size of socket reads that will be
+       offloaded to a DMA copy engine, if one is present in the system
+       and CONFIG_NET_DMA is enabled.
+       Default: 4096
+
 CIPSOv4 Variables:
 
 cipso_cache_enable - BOOLEAN
@@ -854,8 +887,7 @@ accept_redirects - BOOLEAN
 accept_source_route - INTEGER
        Accept source routing (routing extension header).
 
-       > 0: Accept routing header.
-       = 0: Accept only routing header type 2.
+       >= 0: Accept only routing header type 2.
        < 0: Do not accept routing header.
 
        Default: 0
@@ -995,7 +1027,12 @@ bridge-nf-call-ip6tables - BOOLEAN
        Default: 1
 
 bridge-nf-filter-vlan-tagged - BOOLEAN
-       1 : pass bridged vlan-tagged ARP/IP traffic to arptables/iptables.
+       1 : pass bridged vlan-tagged ARP/IP/IPv6 traffic to {arp,ip,ip6}tables.
+       0 : disable this.
+       Default: 1
+
+bridge-nf-filter-pppoe-tagged - BOOLEAN
+       1 : pass bridged pppoe-tagged IP/IPv6 traffic to {ip,ip6}tables.
        0 : disable this.
        Default: 1