2. Serial Protocols
ROS® v3.11User Guide
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RMC30
Address Learning for TIN Mode 1
When a message with an unknown source address is received from the IP network, it is learned
on the IP address and IP port. If a message with the same source address is received from
another IP address and/or IP port, the address will be relearned.
The aging time will be reset whenever a unicast TIN message is received from a particular
source address.
The address will be removed from the table when the aging time expires.
Address Learning for TIN Mode 2
When a message with an unknown source address is received from the IP network, it is learned
on the IP address. If a message with the same source address is received from another IP
address and/or IP port, it will be learned again, and another entry will be created in the Dynamic
Device Address Table (TIN addresses will be duplicated).
Aging time will be reset whenever a unicast TIN message is received from a particular source
address.
The address will be removed from the table when the aging time expires.
2.2.3.2.2. Address Learning for DNP
For the DNP protocol, both the local and remote concepts of address learning are
implemented. Source addresses are learned from messages received from the network for
specific IP Addresses. Source addresses from messages received from the serial ports are
learned for specific local serial ports.
Although the DNP protocol can be configured for TCP or UDP transport, UDP transport is used
during the address learning phase as it supports all types of IP addresses: unicast, multicast
and broadcast.
When a message with an unknown source address is received from the local serial port, the
address is learned on that port and the local IP address.
When a message with an unknown source address is received from the IP network, on IP
interface that is configured as learning interface, it is learned on the IP address of the sender
and serial port is unknown.
When a message with an unknown destination address is received from a serial port, a UDP
broadcast datagram is transmitted on the UDP port configured for the DNP protocol. The IP
interface that transmits this broadcast is the one configured as the learning interface.
When a message with an unknown destination address is received from the IP network, it is
sent to all DNP serial ports.
All learned addresses will be kept in the Device Address Table until they are active. They
will also be saved in non-volatile memory and recovered if the device reboots, so the
learning process does not have to be repeated because of, for example, an accidental power
interruption.
The aging timer is reset whenever a message is received or sent to the specified address.
This concept makes the DNP protocol configurable with the minimum number of parameters:
an IP port, a learning IP interface and an aging timer.
