'\" t
.\"     Title: zmq_udp
.\"    Author: [see the "AUTHORS" section]
.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
.\"      Date: 09/06/2020
.\"    Manual: 0MQ Manual
.\"    Source: 0MQ 4.3.1
.\"  Language: English
.\"
.TH "ZMQ_UDP" "7" "09/06/2020" "0MQ 4\&.3\&.1" "0MQ Manual"
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.ie \n(.g .ds Aq \(aq
.el       .ds Aq '
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.SH "NAME"
zmq_udp \- 0MQ UDP multicast and unicast transport
.SH "SYNOPSIS"
.sp
UDP is unreliable protocol transport of data over IP networks\&. UDP support both unicast and multicast communication\&.
.SH "DESCRIPTION"
.sp
UDP transport can only be used with the \fIZMQ_RADIO\fR and \fIZMQ_DISH\fR socket types\&.
.SH "ADDRESSING"
.sp
A 0MQ endpoint is a string consisting of a \fItransport\fR:// followed by an \fIaddress\fR\&. The \fItransport\fR specifies the underlying protocol to use\&. The \fIaddress\fR specifies the transport\-specific address to connect to\&.
.sp
For the UDP transport, the transport is udp\&. The meaning of the \fIaddress\fR part is defined below\&.
.sp
Binding a socket
.sp
.if n \{\
.RS 4
.\}
.nf
With \*(Aqudp\*(Aq we can only bind the \*(AqZMQ_DISH\*(Aq socket type\&.
When binding a socket using _zmq_bind()_ with the \*(Aqudp\*(Aq
transport the \*(Aqendpoint\*(Aq shall be interpreted as an \*(Aqinterface\*(Aq followed by a
colon and the UDP port number to use\&.

An \*(Aqinterface\*(Aq may be specified by either of the following:

* The wild\-card `*`, meaning all available interfaces\&.
* The name of the network interface (i\&.e\&. eth0, lo, wlan0 etc\&.\&.\&.)
* The primary address assigned to the interface, in its numeric representation\&.
* Multicast address in its numeric representation the socket should join\&.

The UDP port number may be specified a numeric value, usually above
1024 on POSIX systems\&.

Connecting a socket
.fi
.if n \{\
.RE
.\}
.sp
With \fIudp\fR we can only connect the \fIZMQ_RADIO\fR socket type\&. When connecting a socket to a peer address using \fIzmq_connect()\fR with the \fIudp\fR transport, the \fIendpoint\fR shall be interpreted as a \fIpeer address\fR followed by a colon and the UDP port number to use\&.
.sp
A \fIpeer address\fR may be specified by either of the following:
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
The IPv4 or IPv6 address of the peer, in its numeric representation or using its hostname\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
Multicast address in its numeric representation\&.
.RE
.SH "EXAMPLES"
.PP
\fBBinding a socket\fR. 
.sp
.if n \{\
.RS 4
.\}
.nf
//  Unicast \- UDP port 5555 on all available interfaces
rc = zmq_bind(dish, "udp://*:5555");
assert (rc == 0);
//  Unicast \- UDP port 5555 on the local loop\-back interface
rc = zmq_bind(dish, "udp://127\&.0\&.0\&.1:5555");
assert (rc == 0);
//  Unicast \- UDP port 5555 on interface eth1
rc = zmq_bind(dish, "udp://eth1:5555");
assert (rc == 0);
//  Multicast \- UDP port 5555 on a Multicast address
rc = zmq_bind(dish, "udp://239\&.0\&.0\&.1:5555");
assert (rc == 0);
//  Same as above but joining only on interface eth0
rc = zmq_bind(dish, "udp://eth0;239\&.0\&.0\&.1:5555");
assert (rc == 0);
//  Same as above using IPv6 multicast
rc = zmq_bind(dish, "udp://eth0;[ff02::1]:5555");
assert (rc == 0);
.fi
.if n \{\
.RE
.\}
.PP
\fBConnecting a socket\fR. 
.sp
.if n \{\
.RS 4
.\}
.nf
//  Connecting using an Unicast IP address
rc = zmq_connect(radio, "udp://192\&.168\&.1\&.1:5555");
assert (rc == 0);
//  Connecting using a Multicast address
rc = zmq_connect(socket, "udp://239\&.0\&.0\&.1:5555);
assert (rc == 0);
//  Connecting using a Multicast address using local interface wlan0
rc = zmq_connect(socket, "udp://wlan0;239\&.0\&.0\&.1:5555);
assert (rc == 0);
//  Connecting to IPv6 multicast
rc = zmq_connect(socket, "udp://[ff02::1]:5555);
assert (rc == 0);
.fi
.if n \{\
.RE
.\}
.sp
.SH "SEE ALSO"
.sp
\fBzmq_connect\fR(3) \fBzmq_setsockopt\fR(3) \fBzmq_tcp\fR(7) \fBzmq_ipc\fR(7) \fBzmq_inproc\fR(7) \fBzmq_vmci\fR(7) \fBzmq\fR(7)
.SH "AUTHORS"
.sp
This page was written by the 0MQ community\&. To make a change please read the 0MQ Contribution Policy at \m[blue]\fBhttp://www\&.zeromq\&.org/docs:contributing\fR\m[]\&.