
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.
     


