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" + note + "</div>"; spans[i].innerHTML = "[<a id='_footnoteref_" + n + "' href='#_footnote_" + n + "' title='View footnote' class='footnote'>" + n + "</a>]"; var id =spans[i].getAttribute("id"); if (id != null) refs["#"+id] = n; } } if (n == 0) noteholder.parentNode.removeChild(noteholder); else { // Process footnoterefs. for (i=0; i<spans.length; i++) { if (spans[i].className == "footnoteref") { var href = spans[i].getElementsByTagName("a")[0].getAttribute("href"); href = href.match(/#.*/)[0]; // Because IE return full URL. n = refs[href]; spans[i].innerHTML = "[<a href='#_footnote_" + n + "' title='View footnote' class='footnote'>" + n + "</a>]"; } } } } } /*]]>*/ </script> </head> <body> <div id="header"> <h1> zmq_tcp(7) Manual Page </h1> <h2>NAME</h2> <div class="sectionbody"> <p>zmq_tcp - 0MQ unicast transport using TCP </p> </div> </div> <div id="content"> <h2 id="_synopsis">SYNOPSIS</h2> <div class="sectionbody"> <div class="paragraph"><p>TCP is an ubiquitous, reliable, unicast transport. When connecting distributed applications over a network with ØMQ, using the TCP transport will likely be your first choice.</p></div> </div> <h2 id="_addressing">ADDRESSING</h2> <div class="sectionbody"> <div class="paragraph"><p>A ØMQ address string consists of two parts as follows: <em>transport</em><tt>://</tt><em>endpoint</em>. The <em>transport</em> part specifies the underlying transport protocol to use, and for the TCP transport shall be set to <tt>tcp</tt>. The meaning of the <em>endpoint</em> part for the TCP transport is defined below.</p></div> <h3 id="_assigning_a_local_address_to_a_socket">Assigning a local address to a socket</h3><div style="clear:left"></div> <div class="paragraph"><p>When assigning a local address to a socket using <em>zmq_bind()</em> with the <em>tcp</em> transport, the <em>endpoint</em> shall be interpreted as an <em>interface</em> followed by a colon and the TCP port number to use.</p></div> <div class="paragraph"><p>An <em>interface</em> may be specified by either of the following:</p></div> <div class="ulist"><ul> <li> <p> The wild-card <tt>*</tt>, meaning all available interfaces. </p> </li> <li> <p> The primary IPv4 address assigned to the interface, in its numeric representation. </p> </li> <li> <p> The interface name as defined by the operating system. </p> </li> </ul></div> <div class="admonitionblock"> <table><tr> <td class="icon"> <div class="title">Note</div> </td> <td class="content">Interface names are not standardised in any way and should be assumed to be arbitrary and platform dependent. On Win32 platforms no short interface names exist, thus only the primary IPv4 address may be used to specify an <em>interface</em>.</td> </tr></table> </div> <h3 id="_connecting_a_socket">Connecting a socket</h3><div style="clear:left"></div> <div class="paragraph"><p>When connecting a socket to a peer address using <em>zmq_connect()</em> with the <em>tcp</em> transport, the <em>endpoint</em> shall be interpreted as a <em>peer address</em> followed by a colon and the TCP port number to use.</p></div> <div class="paragraph"><p>A <em>peer address</em> may be specified by either of the following:</p></div> <div class="ulist"><ul> <li> <p> The DNS name of the peer. </p> </li> <li> <p> The IPv4 address of the peer, in its numeric representation. </p> </li> </ul></div> </div> <h2 id="_wire_format">WIRE FORMAT</h2> <div class="sectionbody"> <div class="paragraph"><p>ØMQ messages are transmitted over TCP in frames consisting of an encoded <em>payload length</em>, followed by a <em>flags</em> field and the message body. The <em>payload length</em> is defined as the combined length in octets of the message body and the <em>flags</em> field.</p></div> <div class="paragraph"><p>For frames with a <em>payload length</em> not exceeding 254 octets, the <em>payload length</em> shall be encoded as a single octet. The minimum valid <em>payload length</em> of a frame is 1 octet, thus a <em>payload length</em> of 0 octets is invalid and such frames SHOULD be ignored.</p></div> <div class="paragraph"><p>For frames with a <em>payload length</em> exceeding 254 octets, the <em>payload length</em> shall be encoded as a single octet with the value <tt>255</tt> followed by the <em>payload length</em> represented as a 64-bit unsigned integer in network byte order.</p></div> <div class="paragraph"><p>The <em>flags</em> field consists of a single octet containing various control flags:</p></div> <div class="paragraph"><p>Bit 0 (MORE): <em>More message parts to follow</em>. A value of 0 indicates that there are no more message parts to follow; or that the message being sent is not a multi-part message. A value of 1 indicates that the message being sent is a multi-part message and more message parts are to follow.</p></div> <div class="paragraph"><p>Bits 1-7: <em>Reserved</em>. Bits 1-7 are reserved for future expansion and MUST be set to zero.</p></div> <div class="paragraph"><p>The following ABNF grammar represents a single <em>frame</em>:</p></div> <div class="literalblock"> <div class="content"> <pre><tt> frame = (length flags data) length = OCTET / (escape 8OCTET) flags = OCTET escape = %xFF data = *OCTET</tt></pre> </div></div> <div class="paragraph"><p>The following diagram illustrates the layout of a frame with a <em>payload length</em> not exceeding 254 octets:</p></div> <div class="literalblock"> <div class="content"> <pre><tt>0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Payload length| Flags | Message body ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Message body ... +-+-+-+-+-+-+- ...</tt></pre> </div></div> <div class="paragraph"><p>The following diagram illustrates the layout of a frame with a <em>payload length</em> exceeding 254 octets:</p></div> <div class="literalblock"> <div class="content"> <pre><tt>0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 0xff | Payload length ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Payload length ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Payload length| Flags | Message body ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Message body ... +-+-+-+-+-+-+-+ ...</tt></pre> </div></div> </div> <h2 id="_examples">EXAMPLES</h2> <div class="sectionbody"> <div class="listingblock"> <div class="title">Assigning a local address to a socket</div> <div class="content"> <pre><tt>/* TCP port 5555 on all available interfaces */ rc = zmq_bind(socket, "tcp://*:5555"); assert (rc == 0); /* TCP port 5555 on the local loop-back interface on all platforms */ rc = zmq_bind(socket, "tcp://127.0.0.1:5555"); assert (rc == 0); /* TCP port 5555 on the first Ethernet network interface on Linux */ rc = zmq_bind(socket, "tcp://eth0:5555"); assert (rc == 0);</tt></pre> </div></div> <div class="listingblock"> <div class="title">Connecting a socket</div> <div class="content"> <pre><tt>/* Connecting using an IP address */ rc = zmq_connect(socket, "tcp://192.168.1.1:5555"); assert (rc == 0); /* Connecting using a DNS name */ rc = zmq_connect(socket, "tcp://server1:5555"); assert (rc == 0);</tt></pre> </div></div> </div> <h2 id="_see_also">SEE ALSO</h2> <div class="sectionbody"> <div class="paragraph"><p><a href="zmq_bind.html">zmq_bind(3)</a> <a href="zmq_connect.html">zmq_connect(3)</a> <a href="zmq_pgm.html">zmq_pgm(7)</a> <a href="zmq_ipc.html">zmq_ipc(7)</a> <a href="zmq_inproc.html">zmq_inproc(7)</a> <a href="zmq.html">zmq(7)</a></p></div> </div> <h2 id="_authors">AUTHORS</h2> <div class="sectionbody"> <div class="paragraph"><p>This ØMQ manual page was written by Martin Sustrik <<a href="mailto:sustrik@250bpm.com">sustrik@250bpm.com</a>> and Martin Lucina <<a href="mailto:mato@kotelna.sk">mato@kotelna.sk</a>>.</p></div> </div> </div> <div id="footnotes"><hr /></div> <div id="footer"> <div id="footer-text"> ØMQ 2.1.10<br /> Last updated 2011-08-23 16:01:49 CDT </div> </div> </body> </html>