zmq_tcp - 0MQ unicast transport using TCP
TCP is an ubiquitous, reliable, unicast transport. When connecting distributed applications over a network with 0MQ, using the TCP transport will likely be your first choice.
A 0MQ endpoint is a string consisting of a transport
:// followed by an
address. The transport specifies the underlying protocol to use. The
address specifies the transport-specific address to connect to.
For the TCP transport, the transport is
tcp, and the meaning of the
address part is defined below.
Assigning a local address to a socket
When assigning a local address to a socket using zmq_bind() with the tcp transport, the endpoint shall be interpreted as an interface followed by a colon and the TCP port number to use.
An interface may be specified by either of the following:
*, meaning all available interfaces.
The primary IPv4 or IPv6 address assigned to the interface, in its numeric representation.
The non-portable interface name as defined by the operating system.
The TCP port number may be specified by:
A numeric value, usually above 1024 on POSIX systems.
*, meaning a system-assigned ephemeral port.
When using ephemeral ports, the caller should retrieve the actual assigned port using the ZMQ_LAST_ENDPOINT socket option. See zmq_getsockopt for details.
Connecting a socket
When connecting a socket to a peer address using zmq_connect() with the tcp transport, the endpoint shall be interpreted as a peer address followed by a colon and the TCP port number to use.
A peer address may be specified by either of the following:
The DNS name of the peer.
The IPv4 or IPv6 address of the peer, in its numeric representation.
Note: A description of the ZeroMQ Message Transport Protocol (ZMTP) which is used by the TCP transport can be found at http://rfc.zeromq.org/spec:15
// 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);
// 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);
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