X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=Documentation%2Fnetworking%2Fip-sysctl.txt;h=26364d06ae927f0262e4cbccda03d1ad2cca35ba;hb=987b0145d94eecf292d8b301228356f44611ab7c;hp=a2c893a7475d799ec0fd7c32a891f48141a6029a;hpb=5167311cae6aa3a5ff5afd39f88c32a435c969ef;p=linux-2.6.git diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index a2c893a74..26364d06a 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -46,6 +46,29 @@ ipfrag_secret_interval - INTEGER for the hash secret) for IP fragments. Default: 600 +ipfrag_max_dist - INTEGER + ipfrag_max_dist is a non-negative integer value which defines the + maximum "disorder" which is allowed among fragments which share a + common IP source address. Note that reordering of packets is + not unusual, but if a large number of fragments arrive from a source + IP address while a particular fragment queue remains incomplete, it + probably indicates that one or more fragments belonging to that queue + have been lost. When ipfrag_max_dist is positive, an additional check + is done on fragments before they are added to a reassembly queue - if + ipfrag_max_dist (or more) fragments have arrived from a particular IP + address between additions to any IP fragment queue using that source + address, it's presumed that one or more fragments in the queue are + lost. The existing fragment queue will be dropped, and a new one + started. An ipfrag_max_dist value of zero disables this check. + + Using a very small value, e.g. 1 or 2, for ipfrag_max_dist can + result in unnecessarily dropping fragment queues when normal + reordering of packets occurs, which could lead to poor application + performance. Using a very large value, e.g. 50000, increases the + likelihood of incorrectly reassembling IP fragments that originate + from different IP datagrams, which could result in data corruption. + Default: 64 + INET peer storage: inet_peer_threshold - INTEGER @@ -78,6 +101,11 @@ inet_peer_gc_maxtime - INTEGER TCP variables: +tcp_abc - INTEGER + Controls Appropriate Byte Count defined in RFC3465. If set to + 0 then does congestion avoid once per ack. 1 is conservative + value, and 2 is more agressive. + tcp_syn_retries - INTEGER Number of times initial SYNs for an active TCP connection attempt will be retransmitted. Should not be higher than 255. Default value @@ -304,63 +332,12 @@ tcp_low_latency - BOOLEAN changed would be a Beowulf compute cluster. Default: 0 -tcp_westwood - BOOLEAN - Enable TCP Westwood+ congestion control algorithm. - TCP Westwood+ is a sender-side only modification of the TCP Reno - protocol stack that optimizes the performance of TCP congestion - control. It is based on end-to-end bandwidth estimation to set - congestion window and slow start threshold after a congestion - episode. Using this estimation, TCP Westwood+ adaptively sets a - slow start threshold and a congestion window which takes into - account the bandwidth used at the time congestion is experienced. - TCP Westwood+ significantly increases fairness wrt TCP Reno in - wired networks and throughput over wireless links. - Default: 0 - -tcp_vegas_cong_avoid - BOOLEAN - Enable TCP Vegas congestion avoidance algorithm. - TCP Vegas is a sender-side only change to TCP that anticipates - the onset of congestion by estimating the bandwidth. TCP Vegas - adjusts the sending rate by modifying the congestion - window. TCP Vegas should provide less packet loss, but it is - not as aggressive as TCP Reno. - Default:0 - -tcp_bic - BOOLEAN - Enable BIC TCP congestion control algorithm. - BIC-TCP is a sender-side only change that ensures a linear RTT - fairness under large windows while offering both scalability and - bounded TCP-friendliness. The protocol combines two schemes - called additive increase and binary search increase. When the - congestion window is large, additive increase with a large - increment ensures linear RTT fairness as well as good - scalability. Under small congestion windows, binary search - increase provides TCP friendliness. - Default: 0 - -tcp_bic_low_window - INTEGER - Sets the threshold window (in packets) where BIC TCP starts to - adjust the congestion window. Below this threshold BIC TCP behaves - the same as the default TCP Reno. - Default: 14 - -tcp_bic_fast_convergence - BOOLEAN - Forces BIC TCP to more quickly respond to changes in congestion - window. Allows two flows sharing the same connection to converge - more rapidly. - Default: 1 - -tcp_default_win_scale - INTEGER - Sets the minimum window scale TCP will negotiate for on all - conections. - Default: 7 - tcp_tso_win_divisor - INTEGER This allows control over what percentage of the congestion window can be consumed by a single TSO frame. The setting of this parameter is a choice between burstiness and building larger TSO frames. - Default: 8 + Default: 3 tcp_frto - BOOLEAN Enables F-RTO, an enhanced recovery algorithm for TCP retransmission @@ -368,6 +345,11 @@ tcp_frto - BOOLEAN where packet loss is typically due to random radio interference rather than intermediate router congestion. +tcp_congestion_control - STRING + Set the congestion control algorithm to be used for new + connections. The algorithm "reno" is always available, but + additional choices may be available based on kernel configuration. + somaxconn - INTEGER Limit of socket listen() backlog, known in userspace as SOMAXCONN. Defaults to 128. See also tcp_max_syn_backlog for additional tuning @@ -401,10 +383,14 @@ ip_dynaddr - BOOLEAN Default: 0 icmp_echo_ignore_all - BOOLEAN + If set non-zero, then the kernel will ignore all ICMP ECHO + requests sent to it. + Default: 0 + icmp_echo_ignore_broadcasts - BOOLEAN - If either is set to true, then the kernel will ignore either all - ICMP ECHO requests sent to it or just those to broadcast/multicast - addresses, respectively. + If set non-zero, then the kernel will ignore all ICMP ECHO and + TIMESTAMP requests sent to it via broadcast/multicast. + Default: 1 icmp_ratelimit - INTEGER Limit the maximal rates for sending ICMP packets whose type matches @@ -441,6 +427,23 @@ icmp_ignore_bogus_error_responses - BOOLEAN will avoid log file clutter. Default: FALSE +icmp_errors_use_inbound_ifaddr - BOOLEAN + + If zero, icmp error messages are sent with the primary address of + the exiting interface. + + If non-zero, the message will be sent with the primary address of + the interface that received the packet that caused the icmp error. + This is the behaviour network many administrators will expect from + a router. And it can make debugging complicated network layouts + much easier. + + Note that if no primary address exists for the interface selected, + then the primary address of the first non-loopback interface that + has one will be used regarldess of this setting. + + Default: 0 + igmp_max_memberships - INTEGER Change the maximum number of multicast groups we can subscribe to. Default: 20