Hirschmann RS20 User Manual page 30

Entering the IP Parameters
Example of how the network mask is used
In a large network it is possible that gateways and routers separate the
management agent from its management station. How does addressing
work in such a case?
LAN 1
Figure 8: Management agent that is separated from its management station by a
router
The management station "Romeo" wants to send data to the manage-
ment agent "Juliet". Romeo knows Juliet's IP address and also knows that
the router "Lorenzo" knows the way to Juliet.
Romeo therefore puts his message in an envelope and writes Juliet's IP
address as the destination address. For the source address he writes his
own IP address on the envelope.
Romeo then places this envelope in a second one with Lorenzo's MAC
address as the destination and his own MAC address as the source. This
process is comparable to going from layer 3 to layer 2 of the ISO/OSI base
reference model.
Finally, Romeo puts the entire data packet into the mailbox. This is com-
parable to going from layer 2 to layer 1, i.e. to sending the data packet
over the Ethernet.
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Juliet
2.1 IP Parameter Basics
Lorenzo
Romeo
LAN 2
Basic Configuration L2P
Release 4.2 07/08