ip-tcp_metrics(8) [v7 man page]
IP-TCP_METRICS(8) Linux IP-TCP_METRICS(8) NAME
ip-tcp_metrics - management for TCP Metrics SYNOPSIS
ip [ OPTIONS ] tcp_metrics { COMMAND | help } ip tcp_metrics { show | flush } SELECTOR ip tcp_metrics delete [ address ] ADDRESS SELECTOR := [ [ address ] PREFIX ] DESCRIPTION
ip tcp_metrics is used to manipulate entries in the kernel that keep TCP information for IPv4 and IPv6 destinations. The entries are cre- ated when TCP sockets want to share information for destinations and are stored in a cache keyed by the destination address. The saved information may include values for metrics (initially obtained from routes), recent TSVAL for TIME-WAIT recycling purposes, state for the Fast Open feature, etc. For performance reasons the cache can not grow above configured limit and the older entries are replaced with fresh information, sometimes reclaimed and used for new destinations. The kernel never removes entries, they can be flushed only with this tool. ip tcp_metrics show - show cached entries address PREFIX (default) IPv4/IPv6 prefix or address. If no prefix is provided all entries are shown. The output may contain the following information: age <S.MMM>sec - time after the entry was created, reset or updated with metrics from sockets. The entry is reset and refreshed on use with metrics from route if the metrics are not updated in last hour. Not all cached values reset the age on update. cwnd <N> - CWND metric value fo_cookie <HEX-STRING> - Cookie value received in SYN-ACK to be used by Fast Open for next SYNs fo_mss <N> - MSS value received in SYN-ACK to be used by Fast Open for next SYNs fo_syn_drops <N>/<S.MMM>sec ago - Number of drops of initial outgoing Fast Open SYNs with data detected by monitoring the received SYN-ACK after SYN retransmission. The seconds show the time after last SYN drop and together with the drop count can be used to disable Fast Open for some time. reordering <N> - Reordering metric value rtt <N>us - RTT metric value rttvar <N>us - RTTVAR metric value ssthresh <SSTHRESH> - SSTHRESH metric value tw_ts <TSVAL>/<SEC>sec ago - recent TSVAL and the seconds after saving it into TIME-WAIT socket ip tcp_metrics delete - delete single entry address ADDRESS (default) IPv4/IPv6 address. The address is a required argument. ip tcp_metrics flush - flush entries This command flushes the entries selected by some criteria. This command has the same arguments as show. EXAMPLES
ip tcp_metrics show address 192.168.0.0/24 Shows the entries for destinations from subnet ip tcp_metrics show 192.168.0.0/24 The same but address keyword is optional ip tcp_metrics Show all is the default action ip tcp_metrics delete 192.168.0.1 Removes the entry for 192.168.0.1 from cache. ip tcp_metrics flush 192.168.0.0/24 Removes entries for destinations from subnet ip tcp_metrics flush all Removes all entries from cache ip -6 tcp_metrics flush all Removes all IPv6 entries from cache keeping the IPv4 entries. SEE ALSO
ip(8) AUTHOR
Original Manpage by Julian Anastasov <ja@ssi.bg> iproute2 23 Aug 2012 IP-TCP_METRICS(8)
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IP(8) Linux IP(8) NAME
ip - show / manipulate routing, network devices, interfaces and tunnels SYNOPSIS
ip [ OPTIONS ] OBJECT { COMMAND | help } ip [ -force ] -batch filename OBJECT := { link | address | addrlabel | route | rule | neigh | ntable | tunnel | tuntap | maddress | mroute | mrule | monitor | xfrm | netns | l2tp | tcp_metrics | token | macsec } OPTIONS := { -V[ersion] | -h[uman-readable] | -s[tatistics] | -d[etails] | -r[esolve] | -iec | -f[amily] { inet | inet6 | ipx | dnet | link } | -4 | -6 | -I | -D | -B | -0 | -l[oops] { maximum-addr-flush-attempts } | -o[neline] | -rc[vbuf] [size] | -t[imestamp] | -ts[hort] | -n[etns] name | -a[ll] | -c[olor] -br[ief] } OPTIONS
-V, -Version Print the version of the ip utility and exit. -h, -human, -human-readable output statistics with human readable values followed by suffix. -b, -batch <FILENAME> Read commands from provided file or standard input and invoke them. First failure will cause termination of ip. -force Don't terminate ip on errors in batch mode. If there were any errors during execution of the commands, the application return code will be non zero. -s, -stats, -statistics Output more information. If the option appears twice or more, the amount of information increases. As a rule, the information is statistics or some time values. -d, -details Output more detailed information. -l, -loops <COUNT> Specify maximum number of loops the 'ip address flush' logic will attempt before giving up. The default is 10. Zero (0) means loop until all addresses are removed. -f, -family <FAMILY> Specifies the protocol family to use. The protocol family identifier can be one of inet, inet6, bridge, ipx, dnet, mpls or link. If this option is not present, the protocol family is guessed from other arguments. If the rest of the command line does not give enough information to guess the family, ip falls back to the default one, usually inet or any. link is a special family identifier meaning that no networking protocol is involved. -4 shortcut for -family inet. -6 shortcut for -family inet6. -B shortcut for -family bridge. -D shortcut for -family decnet. -I shortcut for -family ipx. -M shortcut for -family mpls. -0 shortcut for -family link. -o, -oneline output each record on a single line, replacing line feeds with the '' character. This is convenient when you want to count records with wc(1) or to grep(1) the output. -r, -resolve use the system's name resolver to print DNS names instead of host addresses. -n, -netns <NETNS> switches ip to the specified network namespace NETNS. Actually it just simplifies executing of: ip netns exec NETNS ip [ OPTIONS ] OBJECT { COMMAND | help } to ip -n[etns] NETNS [ OPTIONS ] OBJECT { COMMAND | help } -a, -all executes specified command over all objects, it depends if command supports this option. -c, -color Use color output. -t, -timestamp display current time when using monitor option. -ts, -tshort Like -timestamp, but use shorter format. -rc, -rcvbuf<SIZE> Set the netlink socket receive buffer size, defaults to 1MB. -iec print human readable rates in IEC units (e.g. 1Ki = 1024). -br,-brief Print only basic information in a tabular format for better readability. This option is currently only supported by ip addr show and ip link show commands. IP - COMMAND SYNTAX OBJECT address - protocol (IP or IPv6) address on a device. addrlabel - label configuration for protocol address selection. l2tp - tunnel ethernet over IP (L2TPv3). link - network device. maddress - multicast address. monitor - watch for netlink messages. mroute - multicast routing cache entry. mrule - rule in multicast routing policy database. neighbour - manage ARP or NDISC cache entries. netns - manage network namespaces. ntable - manage the neighbor cache's operation. route - routing table entry. rule - rule in routing policy database. tcp_metrics/tcpmetrics - manage TCP Metrics token - manage tokenized interface identifiers. tunnel - tunnel over IP. tuntap - manage TUN/TAP devices. xfrm - manage IPSec policies. The names of all objects may be written in full or abbreviated form, for example address can be abbreviated as addr or just a. COMMAND Specifies the action to perform on the object. The set of possible actions depends on the object type. As a rule, it is possible to add, delete and show (or list ) objects, but some objects do not allow all of these operations or have some additional commands. The help com- mand is available for all objects. It prints out a list of available commands and argument syntax conventions. If no command is given, some default command is assumed. Usually it is list or, if the objects of this class cannot be listed, help. EXIT STATUS
Exit status is 0 if command was successful, and 1 if there is a syntax error. If an error was reported by the kernel exit status is 2. EXAMPLES
ip addr Shows addresses assigned to all network interfaces. ip neigh Shows the current neighbour table in kernel. ip link set x up Bring up interface x. ip link set x down Bring down interface x. ip route Show table routes. HISTORY
ip was written by Alexey N. Kuznetsov and added in Linux 2.2. SEE ALSO
ip-address(8), ip-addrlabel(8), ip-l2tp(8), ip-link(8), ip-maddress(8), ip-monitor(8), ip-mroute(8), ip-neighbour(8), ip-netns(8), ip- ntable(8), ip-route(8), ip-rule(8), ip-tcp_metrics(8), ip-token(8), ip-tunnel(8), ip-xfrm(8) IP Command reference ip-cref.ps REPORTING BUGS
Report any bugs to the Network Developers mailing list <netdev@vger.kernel.org> where the development and maintenance is primarily done. You do not have to be subscribed to the list to send a message there. AUTHOR
Original Manpage by Michail Litvak <mci@owl.openwall.com> iproute2 20 Dec 2011 IP(8)