Transport Connection Tpv - Siemens SINUMERIK 840 Planning Manual

06.91 1 General

1.1.6 Transport connection TPV

1.1.6 Transport connection TPV
The term transport connection describes a virtual connection between two nodes in a network
which, in accordance with the ISO reference model, is also referred to as layer 4 connection
since it reaches to layer 4 of the respective communication partner.
In the case of a serial link, the transport connection need not be specified since an
unambiguous hardware allocation is made by the interface used.
The transport connection is determined by addresses which are clearly assigned when the
network is configured. By means of the addresses the two end points of the transport
connection are allocated.
In the case of a computer link with SINUMERIK 8X0, a transport connection is determined by
the address pair's own Ethernet address, the internal TSAP (Transport Service Access Point)
and the Ethernet and TSAP address of the partner. The addresses or the allocations for the
corresponding transport connection are stored in the interface module of the SINUMERIK 8X0.
The transport connection provides a reliable communication connection to transfer the
application-oriented information and it manages the transfer-specific services.
Several transport connections can be configured for one system. For example, a different
transport connection can be used for the file transfer (NC data exchange) than for the
loading/unloading of tools.
Access to the transport connection is from the application-oriented layers via the transport
service access point (TSAP), which has its own unique address (TSAP address).
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