Rockwell Automation 1768-EWEB EtherNet/IP Web Server Module User Manual User Manual

Page 127

Publication ENET-UM527E-EN-P - October 2006

Socket Interface 127

You can partition the 20 available socket instances between UDP and
TCP sockets. For example:

• Use all 20 instances for client TCP connections
• Use one instance to listen for incoming TCP connections and

then accept 19 connections from other device

• Perform both TCP client and server operations
• Perform both TCP and UDP operations

These socket services are available.

Once you open a connection on a client socket instance, you cannot
use the same socket instance to accept incoming connections.
Similarly, if you accept connections on a socket instance, you cannot
then use the instance to open outgoing connections. This behavior is
consistent with standard socket API behavior.

This Socket Service

The Socket Instance Is

See Page

CreateSocket

Server or client

141

OpenConnection

Client

143

AcceptConnection

• if you issue an AcceptConnection service, the instance is listen type
• if the AcceptConnection service returns an instance as a result of an

incoming connection request, the socket instance is server type