Siemens SIMATIC NET S7-300 Manual page 31

1.5 S5-compatible Communication (SEND/RECEIVE
Interface)
Application
Using the SEND/RECEIVE interface, your S7 user program has access to
S5-compatible communication with configured transport connections.
Data transmission over a configured transport connection is suitable for the
following types of transmission:
S the reliable transmission of related blocks of data between two Ethernet nodes
using
- TCP (see /13/) with ISO-on-TCP connection (see /14/) or TCP connection;
- ISO transport connection (not with PROFINET CBA).
S simple (unacknowledged) transfer of related blocks of data (datagram service)
between two Ethernet nodes with UDP (User Datagram Protocol) on IP.
The SEND/RECEIVE interface is also suitable for sending E-mail (refer to the
manual for the IT-CP /5/).
For TCP applications, there is an active network with IP protocol (see /16/).
ISO Transport Connection
ISO transport provides services for the reliable transfer of data on configured
connections. Due to segmentation (packet-oriented segmentation - the
completeness of the message is detected) large amounts of data can be
transmitted.
Transmission reliability is extremely high due to automatic repetition and additional
field check mechanisms. The communications partner confirms reception of data
and the sender receives a return value on the SEND/RECEIVE interface.
ISO transport is operated only on Industrial Ethernet and is optimized for
high-performance operation at the self-contained manufacturing level.
1) The previous name of the SEND/RECEIVE interface was S5S5 connections
S7-CPs for Industrial Ethernet Configuring and Commissioning
Release 01/2007
C79000-G8976-C182-07
1 Communication via Ethernet CPs in S7 Stations
1)
A -31