Network Topology With Redundancy (Prp) - Siemens SIMATIC NET S7-400 Manual

– LOCK/UNLOCK with FETCH/WRITE services (CPUdependent; see section
● Open TCP/IP communication
Open TCP/IP communication provides a program interface for the transfer of connection-
oriented and connectionless services. The establishment and termination of connections
is initiated here only via the "dynamic" program interface.
STEP 7 provides a UDT for the connection parameter assignment as well as four FBs for
high-speed data exchange.
The CP supports communication via ISO-on-TCP connections for this interface.
Interfaces used and communications services
The following table provides an overview of the services available at the interfaces.
Communications service
S7 communication
Open communications
services using
SEND/RECEIVE inter-
face
Open TCP/IP commu-
nication
Time of day
H connections
1.3

Network topology with redundancy (PRP)

Redundant Network Access (RNA)
In Siemens Industry, Redundant Network Access (RNA) stands for devices and software that
support the redundancy protocol "Parallel Redundancy Protocol" (PRP). RNA allows the
connection of devices to redundant Ethernet network structures.
The product names of the RNA devices end with "RNA".
CP 443-1 RNA
Manual, 03/2019, C79000-G8976-C299-04
establishment) is always initiated by a SIMATIC S5 or a device from another range /
PC.
Requirements for use (Page 23));
PG functions; operator control and monitoring
functions (ISO)
PG functions; operator control and monitoring
functions (ISO-on-TCP)
Data exchange over S7 connections (ISO)
Data exchange over S7 connections (TCP)
ISO transport connections
TCP connections, ISOonTCP and UDP connec-
tions
Multicast over UDP connection
FETCH/WRITE services (ISO)
FETCH/WRITE services (RFC, TCP)
NTP mode and SIMATIC mode
via ISO
via TCP
Application and functions
1.3 Network topology with redundancy (PRP)
Ethernet interface
x
-
x
-
x
-
-
x
-
-
-
x
-
RNA interface
x
x
x
x
x
x
x
x
x
x
x
x
x
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