1 .\" Copyright (c) 2008 George V. Neville-Neil
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40 .Op Fl t Ar inter-packet gap
41 .Op Fl M Ar number of clients (source only)
42 .Op Fl m Ar my client number (sink only)
47 command implements a multicast test which involved a source
48 and a sink. The source sends packets to a pre-configured
49 multicast address over the interface given as a command line
50 argument. The sink listens for multicast packets, records
51 the time at which they're received and then reflects them back
52 over unicast to the source. When the source has captured all
53 the reflected packets it prints out the round trip time of each.
55 The source prints out the round trip time of packets sent to the
56 sinks. The sink prints out the time between the packets received.
58 The options are as follows:
59 .Bl -tag -width ".Fl d Ar argument"
61 Network interface, which can be found with ifconfig(1).
65 Port on which to listen
71 Inter-packet gap in nanoseconds.
73 The number of clients that are listening
75 The client's number 0, 1, etc.
79 is the receiver aka the sink. This option MUST
80 only be used with one copy of the program at a time.
83 The following is an example of a typical usage
89 .Dl "mctest -i em0 -M 1 -s 1024 -n 100 -t 1"
91 .Dl "mctest -i em0 -m 0 -s 1024 -n 100 -r"
93 Send 100 packets of 1024 bytes, with an inter-packet gap of 1 nanosecond.
95 Gaps are measured with
97 and so are not accurate down to nanoseconds
98 but depend on the setting of kern.hz.
106 program first appeared in
110 manual page was written by
111 .An George V. Neville-Neil Aq gnn@FreeBSD.org .
113 Should be reported to the author or to net@freebsd.org.