libzmq/man/man7/zmq_udp.7

.TH zmq_udp 7 "" "(c)2007-2010 iMatix Corporation" "0MQ User Manuals"
.SH NAME
0MQ UDP Transport \- reliable multicast transport
.SH SYNOPSIS

UDP transport is exactly the same as PGM transport except that PGM packets
are encapsulated in UDP packets. Rationale for this transport is that user-space
implementation of PGM requires right to create raw sockets (PGM is located
directly on top of IP layer in the networking stack), which is often not
available. UDP encapsulation solves this problem, however, it adds some overhead
related to creating and transferring UDP packet headers.

.SH CONNECTION STRING

Connection string for UDP transport is "udp://" followed by an IP address
of the NIC to use, semicolon, IP address of the multicast group, colon and
port number. IP address of the NIC can be either its numeric representation
or the name of the NIC as reported by operating system. IP address of the
multicast group should be specified in the numeric representation. For example:

.nf
    udp://eth0;224.0.0.1:5555
    udp://lo;230.0.0.0:6666
    udp://192.168.0.111;224.0.0.1:5555
.fi

Note that NIC names are not standardised by POSIX. They tend to be rather
arbitrary and platform dependent. Say, "eth0" on Linux would correspond to "en0"
on OSX and "e1000g" on Solaris. On Windows platform, as there are no short NIC
names available, you have to use numeric IP addresses instead.

.SH WIRE FORMAT

Same as with PGM transport except for UDP packet headers.

.SH "SEE ALSO"

.BR zmq_pgm (7)
.BR zmq_tcp (7)
.BR zmq_ipc (7)
.BR zmq_inproc (7)

.SH AUTHOR
Martin Sustrik <sustrik at 250bpm dot com>