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-
- tcp <subcommand>
-
- These commands are used for the Transmission Control Protocol
- service.
-
- Notes:
-
- Attempting outgoing connections to addresses without an
- existing route result in Error number 19.
-
-
- tcp irtt [<milliseconds>]
-
- (B) Display or set the initial round trip time estimate, in
- milliseconds, to be used for new TCP connections until they can
- measure and adapt to the actual value. The default is 5000
- milliseconds (5 seconds). Increasing irtt when operating over
- slow channels will avoid the flurry of re-transmissions that
- would otherwise occur as the smoothed estimate settles down at
- the correct value. Note that this command should be given before
- servers are started in order for it to have effect on incoming
- connections.
-
- TCP also keeps a cache of measured round trip times and mean
- deviations (MDEV) for current and recent destinations. Whenever
- a new TCP connection is opened, the system first looks in this
- cache. If the destination is found, the cached IRTT and MDEV
- values are used. If not, the default IRTT value mentioned above
- is used, along with a MDEV of 0. This feature is fully
- automatic, and it can improve performance greatly when a series
- of connections are opened and closed to a given destination (e.g.
- a series of FTP file transfers or directory listings).
-
-
- tcp kick <tcb_addr>
-
- If there is unacknowledged data on the send queue of the
- specified TCB, this command forces an immediate retransmission.
- <tcb addr> can be found with the 'tcp status' command.
-
-
- tcp maxwait [<msec>]
-
- Set or show the maximum time for retry timeout in milliseconds.
- Default = 0, no maximum.
-
-
- tcp mss [<size>]
-
- (B) Display or set the TCP Maximum Segment Size in bytes that
- will be sent on all outgoing TCP connect request (SYN segments).
- This tells the remote end the size of the largest segment
- (packet) it may send. Changing MSS affects only future
- connections; existing connections are unaffected. See also the
- section ON MTU, etc.
-
-
- tcp reset <tcb_addr>
-
- Deletes the TCP control block at the specified address.
-
-
- tcp retries [<num>]
-
- (B) Display or set the number of retries before a tcp connection
- will be reset. Default is 16. This is useful to eliminate idle
- connections that have not been properly shut down. Default = 0,
- there is no maximum, i.e. a connection will never retry out.
-
-
- tcp rtt <tcb_addr> <milliseconds>
-
- Replaces the automatically computed round trip time in the
- specified TCB with the rtt in milliseconds. This command is
- useful to speed up recovery from a series of lost packets since
- it provides a manual bypass around the normal backoff
- retransmission timing mechanisms.
-
-
- tcp status [<tcb_addr>]
-
- Without arguments, displays several TCP-level statistics, plus a
- summary of all existing TCP connections, including TCB
- address, send and receive queue sizes, local and remote sockets,
- and connection state. If <tcb addr> is specified, a more
- detailed dump of the specified TCB is generated, including send
- and receive sequence numbers and timer information.
-
-
- tcp syndata [yes | no]
-
- (B) Display or set the tcp syn + data piggybacking flag. Some
- tcp systems cannot handle syn + data together.
-
-
- tcp timertype [linear | exponential]
-
- (B) Display the current setting or set the timer type backoff
- algorithm. Default is linear.
-
-
- tcp trace [yes | no]
-
- (B) Display or set the tcp trace flag on or off.
-
-
- tcp window [<size>]
-
- (B) Displays or sets the default receive window size in bytes to
- be used by TCP when creating new connections. Existing
- connections are unaffected.
-
-
-
-