Labels:text | screenshot | font | black and white OCR: Help File tcp These commands are used for the Transmission Control Protocol service. tcp irtt [<milliseconds>] 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 mil- liseconds (5 seconds). Increasing this when operating over slow channels will avoid the flurry of retransmissions that would oth- erwise 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 cache . new TCP connection is opened, the system first looks in this 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 of automatic, and it can improve performance greatly when a series connections are opened and closed to a given destination (eg. a series of FTP file transfers or directory listings). tcp kick <tcb_addr> If there is unacknowledged data on the send queue of the speci- fied TCB, this command forces an immediate retransmission. tcp mss [<size>] 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. tcp reset <tcb_addr> Deletes the TCP control block at the specified address. tcp rtt <tcb_addr> <milliseconds> Replaces the automatically computed round trip time in the speci- fied 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 con- nection 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 timertype [linear lexponential] The TCP timer backoff can be either linear or binary exponential. Linear backoff is recommended for amateur radio work. tcp trace [onloff] Display or set TCP trace mode. When set to 'on', task control block activity is displayed, together with numbered TCP protocol messages . tcp window [<size>] Displays or sets the default receive window size in bytes to be used by TCP when creating new connections. Existing connections are unaffected.
(.png)
