diff options
Diffstat (limited to 'kernel/Documentation/networking/ip-sysctl.txt')
| -rw-r--r-- | kernel/Documentation/networking/ip-sysctl.txt | 112 |
1 files changed, 103 insertions, 9 deletions
diff --git a/kernel/Documentation/networking/ip-sysctl.txt b/kernel/Documentation/networking/ip-sysctl.txt index 071fb18dc..2ea4c45cf 100644 --- a/kernel/Documentation/networking/ip-sysctl.txt +++ b/kernel/Documentation/networking/ip-sysctl.txt @@ -267,6 +267,15 @@ tcp_ecn - INTEGER but do not request ECN on outgoing connections. Default: 2 +tcp_ecn_fallback - BOOLEAN + If the kernel detects that ECN connection misbehaves, enable fall + back to non-ECN. Currently, this knob implements the fallback + from RFC3168, section 6.1.1.1., but we reserve that in future, + additional detection mechanisms could be implemented under this + knob. The value is not used, if tcp_ecn or per route (or congestion + control) ECN settings are disabled. + Default: 1 (fallback enabled) + tcp_fack - BOOLEAN Enable FACK congestion avoidance and fast retransmission. The value is not used, if tcp_sack is not enabled. @@ -375,6 +384,14 @@ tcp_mem - vector of 3 INTEGERs: min, pressure, max Defaults are calculated at boot time from amount of available memory. +tcp_min_rtt_wlen - INTEGER + The window length of the windowed min filter to track the minimum RTT. + A shorter window lets a flow more quickly pick up new (higher) + minimum RTT when it is moved to a longer path (e.g., due to traffic + engineering). A longer window makes the filter more resistant to RTT + inflations such as transient congestion. The unit is seconds. + Default: 300 + tcp_moderate_rcvbuf - BOOLEAN If set, TCP performs receive buffer auto-tuning, attempting to automatically size the buffer (no greater than tcp_rmem[2]) to @@ -416,6 +433,15 @@ tcp_orphan_retries - INTEGER you should think about lowering this value, such sockets may consume significant resources. Cf. tcp_max_orphans. +tcp_recovery - INTEGER + This value is a bitmap to enable various experimental loss recovery + features. + + RACK: 0x1 enables the RACK loss detection for fast detection of lost + retransmissions and tail drops. + + Default: 0x1 + tcp_reordering - INTEGER Initial reordering level of packets in a TCP stream. TCP stack can then dynamically adjust flow reordering level @@ -577,6 +603,21 @@ tcp_min_tso_segs - INTEGER if available window is too small. Default: 2 +tcp_pacing_ss_ratio - INTEGER + sk->sk_pacing_rate is set by TCP stack using a ratio applied + to current rate. (current_rate = cwnd * mss / srtt) + If TCP is in slow start, tcp_pacing_ss_ratio is applied + to let TCP probe for bigger speeds, assuming cwnd can be + doubled every other RTT. + Default: 200 + +tcp_pacing_ca_ratio - INTEGER + sk->sk_pacing_rate is set by TCP stack using a ratio applied + to current rate. (current_rate = cwnd * mss / srtt) + If TCP is in congestion avoidance phase, tcp_pacing_ca_ratio + is applied to conservatively probe for bigger throughput. + Default: 120 + tcp_tso_win_divisor - INTEGER This allows control over what percentage of the congestion window can be consumed by a single TSO frame. @@ -668,7 +709,7 @@ tcp_limit_output_bytes - INTEGER typical pfifo_fast qdiscs. tcp_limit_output_bytes limits the number of bytes on qdisc or device to reduce artificial RTT/cwnd and reduce bufferbloat. - Default: 131072 + Default: 262144 tcp_challenge_ack_limit - INTEGER Limits number of Challenge ACK sent per second, as recommended @@ -742,8 +783,10 @@ IP Variables: ip_local_port_range - 2 INTEGERS Defines the local port range that is used by TCP and UDP to choose the local port. The first number is the first, the - second the last local port number. The default values are - 32768 and 61000 respectively. + second the last local port number. + If possible, it is better these numbers have different parity. + (one even and one odd values) + The default values are 32768 and 60999 respectively. ip_local_reserved_ports - list of comma separated ranges Specify the ports which are reserved for known third-party @@ -766,7 +809,7 @@ ip_local_reserved_ports - list of comma separated ranges ip_local_port_range, e.g.: $ cat /proc/sys/net/ipv4/ip_local_port_range - 32000 61000 + 32000 60999 $ cat /proc/sys/net/ipv4/ip_local_reserved_ports 8080,9148 @@ -1170,6 +1213,17 @@ tag - INTEGER Allows you to write a number, which can be used as required. Default value is 0. +xfrm4_gc_thresh - INTEGER + The threshold at which we will start garbage collecting for IPv4 + destination cache entries. At twice this value the system will + refuse new allocations. The value must be set below the flowcache + limit (4096 * number of online cpus) to take effect. + +igmp_link_local_mcast_reports - BOOLEAN + Enable IGMP reports for link local multicast groups in the + 224.0.0.X range. + Default TRUE + Alexey Kuznetsov. kuznet@ms2.inr.ac.ru @@ -1204,14 +1258,28 @@ flowlabel_consistency - BOOLEAN FALSE: disabled Default: TRUE -auto_flowlabels - BOOLEAN - Automatically generate flow labels based based on a flow hash - of the packet. This allows intermediate devices, such as routers, - to idenfify packet flows for mechanisms like Equal Cost Multipath +auto_flowlabels - INTEGER + Automatically generate flow labels based on a flow hash of the + packet. This allows intermediate devices, such as routers, to + identify packet flows for mechanisms like Equal Cost Multipath Routing (see RFC 6438). + 0: automatic flow labels are completely disabled + 1: automatic flow labels are enabled by default, they can be + disabled on a per socket basis using the IPV6_AUTOFLOWLABEL + socket option + 2: automatic flow labels are allowed, they may be enabled on a + per socket basis using the IPV6_AUTOFLOWLABEL socket option + 3: automatic flow labels are enabled and enforced, they cannot + be disabled by the socket option + Default: 1 + +flowlabel_state_ranges - BOOLEAN + Split the flow label number space into two ranges. 0-0x7FFFF is + reserved for the IPv6 flow manager facility, 0x80000-0xFFFFF + is reserved for stateless flow labels as described in RFC6437. TRUE: enabled FALSE: disabled - Default: false + Default: true anycast_src_echo_reply - BOOLEAN Controls the use of anycast addresses as source addresses for ICMPv6 @@ -1321,6 +1389,14 @@ accept_ra_from_local - BOOLEAN disabled if accept_ra_from_local is disabled on a specific interface. +accept_ra_min_hop_limit - INTEGER + Minimum hop limit Information in Router Advertisement. + + Hop limit Information in Router Advertisement less than this + variable shall be ignored. + + Default: 1 + accept_ra_pinfo - BOOLEAN Learn Prefix Information in Router Advertisement. @@ -1416,6 +1492,11 @@ mtu - INTEGER Default Maximum Transfer Unit Default: 1280 (IPv6 required minimum) +ip_nonlocal_bind - BOOLEAN + If set, allows processes to bind() to non-local IPv6 addresses, + which can be quite useful - but may break some applications. + Default: 0 + router_probe_interval - INTEGER Minimum interval (in seconds) between Router Probing described in RFC4191. @@ -1436,6 +1517,13 @@ router_solicitations - INTEGER routers are present. Default: 3 +use_oif_addrs_only - BOOLEAN + When enabled, the candidate source addresses for destinations + routed via this interface are restricted to the set of addresses + configured on this interface (vis. RFC 6724, section 4). + + Default: false + use_tempaddr - INTEGER Preference for Privacy Extensions (RFC3041). <= 0 : disable Privacy Extensions @@ -1572,6 +1660,12 @@ ratelimit - INTEGER otherwise the minimal space between responses in milliseconds. Default: 1000 +xfrm6_gc_thresh - INTEGER + The threshold at which we will start garbage collecting for IPv6 + destination cache entries. At twice this value the system will + refuse new allocations. The value must be set below the flowcache + limit (4096 * number of online cpus) to take effect. + IPv6 Update by: Pekka Savola <pekkas@netcore.fi> |