DragonFly On-Line Manual Pages

Search: Section:  

TTCP(1)                DragonFly General Commands Manual               TTCP(1)


NAME

       ttcp - test TCP and UDP performance


SYNOPSIS

       ttcp -t [-u] [-s] [-p port] [-l buflen] [-b size] [-n numbufs]
       [-A align] [-O offset] [-f format] [-D] [-v] host [<in]
       ttcp -r [-u] [-s] [-p port] [-l buflen] [-b size] [-A align]
       [-O offset] [-f format] [-B] [-T] [-v] [>out]


DESCRIPTION

       Ttcp times the transmission and reception of data between two systems
       using the UDP or TCP protocols.  It differs from common ``blast''
       tests, which tend to measure the remote inetd as much as the network
       performance, and which usually do not allow measurements at the remote
       end of a UDP transmission.

       For testing, the transmitter should be started with -t and -s after the
       receiver has been started with -r and -s.  Tests lasting at least tens
       of seconds should be used to obtain accurate measurements.  Graphical
       presentations of throughput versus buffer size for buffers ranging from
       tens of bytes to several ``pages'' can illuminate bottlenecks.

       Ttcp can also be used as a ``network pipe'' for moving directory
       hierarchies between systems when routing problems exist or when the use
       of other mechanisms is undesirable. For example, on the destination
       machine, use: ttcp -r -B | tar xvpf -

       and on the source machine: tar cf - directory | ttcp -t dest_machine

       Additional intermediate machines can be included by: ttcp -r | ttcp -t
       next_machine


OPTIONS

       -t        Transmit mode.

       -r        Receive mode.

       -u        Use UDP instead of TCP.

       -s        If transmitting, source a data pattern to network; if
                 receiving, sink (discard) the data.  Without the -s option,
                 the default is to transmit data from stdin or print the
                 received data to stdout.

       -l length Length of buffers in bytes (default 8192).  For UDP, this
                 value is the number of data bytes in each packet.  The system
                 limits the maximum UDP packet length. This limit can be
                 changed with the -b option.

       -b size   Set size of socket buffer.  The default varies from system to
                 system.  This parameter affects the maximum UDP packet
                 length.  It may not be possible to set this parameter on some
                 systems (for example, 4.2BSD).

       -n numbufs
                 Number of source buffers transmitted (default 2048).

       -p port   Port number to send to or listen on (default 2000).  On some
                 systems, this port may be allocated to another network
                 daemon.

       -D        If transmitting using TCP, do not buffer data when sending
                 (sets the TCP_NODELAY socket option).  It may not be possible
                 to set this parameter on some systems (for example, 4.2BSD).

       -B        When receiving data, output only full blocks, using the block
                 size specified by -l.  This option is useful for programs,
                 such as tar(1), that require complete blocks.

       -A align  Align the start of buffers to this modulus (default 16384).

       -O offset Align the start of buffers to this offset (default 0).  For
                 example, ``-A8192 -O1'' causes buffers to start at the second
                 byte of an 8192-byte page.

       -f format Specify, using one of the following characters, the format of
                 the throughput rates as kilobits/sec ('k'), kilobytes/sec
                 ('K'), megabits/sec ('m'), megabytes/sec ('M'), gigabits/sec
                 ('g'), or gigabytes/sec ('G').  The default is 'K'.

       -T        ``Touch'' the data as they are read in order to measure cache
                 effects.

       -v        Verbose: print more statistics.

       -d        Debug: set the SO_DEBUG socket option.


SEE ALSO

       ping(1M), traceroute(1M), netsnoop(1M)

                                     local                             TTCP(1)

Search: Section: