W&T Com-Server++, Руководство пользователя

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W&T
UDP bus mode
14�1 Function of UDP Bus Mode
The Com-Server configured in UDP Bus Mode as a master
sends all received serial data as a broadcast into the network
to the configured UDP port. All slave Com-Servers active on
the addressed UDP port receive these data and forward them
to their serial devices with no content changes. The devices
addressed in the course of this protocol will then formulate
and send their reply.
In the opposite direction from the slave(s) to the master,
network transmission can be directly addressed. If the reply
from a particular serial device also needs to be visible to all
other slaves, this data direction also needs to be handled as
a broadcast.
When using UDP Bus Mode the following prerequisites and
peculiarities need to be taken into account:
• UDP Bus Mode replaces the IP Bus Mode of previous
Com-Server generations. The modes are however not mutually
compatible, so that no mixed installations are possible.
• The serial devices must send their data with their own
security protocol. Since the Com-Servers use connection-less
and unsecured UDP as the network protocol, they cannot pro-
vide data security.
• Since transmission is via broadcast in at least one directi-
on, all devices which form a UDP bus belong to the same sub-
net. This means the subnet mask and the network section of
the IP address must be identical in all Com-Servers. Cross-net-
work communication using routers is not possible.