1TTCP(1) General Commands Manual TTCP(1)
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6 ttcp - test TCP and UDP performance
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9 ttcp -t [-u] [-s] [-p port] [-l buflen] [-b size] [-n numbufs]
10 [-A align] [-O offset] [-f format] [-D] [-v] host
11 ttcp -r [-u] [-s] [-p port] [-l buflen] [-b size] [-A align] [-O off‐
12 set] [-f format] [-B] [-T] [-v]
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15 Ttcp times the transmission and reception of data between two systems
16 using the UDP or TCP protocols. It differs from common ``blast''
17 tests, which tend to measure the remote inetd as much as the network
18 performance, and which usually do not allow measurements at the remote
19 end of a UDP transmission.
20 For testing, the transmitter should be started with -t and -s after the
22 receiver has been started with -r and -s. Tests lasting at least tens
23 of seconds should be used to obtain accurate measurements. Graphical
24 presentations of throughput versus buffer size for buffers ranging from
25 tens of bytes to several ``pages'' can illuminate bottlenecks.
26 Ttcp can also be used as a ``network pipe'' for moving directory hier‐
28 archies between systems when routing problems exist or when the use of
29 other mechanisms is undesirable. For example, on the destination
30 machine, use:
31 ttcp -r -B | tar xvpf -
32 and on the source machine:
34 tar cf - directory | ttcp -t dest_machine
35 Additional intermediate machines can be included by:
37 ttcp -r | ttcp -t next_machine
38
40 -t Transmit mode. Transmit data presented on standard input.
41 -r Receive mode. Send received data to standard output.
43 -u Use UDP instead of TCP.
45 -s If transmitting, source a data pattern to network; if receiv‐
47 ing, sink (discard) the data. Without the -s option, the
48 default is to transmit data from stdin or print the received
49 data to stdout.
50 -l length Length of buffers in bytes (default 8192). For UDP, this
52 value is the number of data bytes in each packet. The system
53 limits the maximum UDP packet length. This limit can be
54 changed with the -b option.
55 -b size Set size of socket buffer. The default varies from system to
57 system. This parameter affects the maximum UDP packet
58 length. It may not be possible to set this parameter on some
59 systems (for example, 4.2BSD).
60 -n numbufs
62 Number of source buffers transmitted (default 2048).
63 -p port Port number to send to or listen on (default 2000). On some
65 systems, this port may be allocated to another network dae‐
66 mon.
67 -D If transmitting using TCP, do not buffer data when sending
69 (sets the TCP_NODELAY socket option). It may not be possible
70 to set this parameter on some systems (for example, 4.2BSD).
71 -B When receiving data, output only full blocks, using the block
73 size specified by -l. This option is useful for programs,
74 such as tar(1), that require complete blocks.
75 -A align Align the start of buffers to this modulus (default 16384).
77 -O offset Align the start of buffers to this offset (default 0). For
79 example, ``-A8192 -O1'' causes buffers to start at the second
80 byte of an 8192-byte page.
81 -f format Specify, using one of the following characters, the format of
83 the throughput rates as kilobits/sec ('k'), kilobytes/sec
84 ('K'), megabits/sec ('m'), megabytes/sec ('M'), gigabits/sec
85 ('g'), or gigabytes/sec ('G'). The default is 'K'.
86 -T ``Touch'' the data as they are read in order to measure cache
88 effects.
89 -v Verbose: print more statistics.
91 -d Debug: set the SO_DEBUG socket option.
93
95 ping(1M), traceroute(1M), netsnoop(1M)
96 local TTCP(1)