Comtech EF Data CRS-300, Installation And Operation Manual

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CRS-300 1:10 Redundancy Switch MN/CRS300.IOM
Appendix A Revision 19
A–12
A.3.8 Hub-to-Remotes, Split-path Traffic using Switches (Point-to-
Multipoint)
With switches used, the hub and remote are on the same subnet as shown in Figure A-13,
meaning that broadcasts will be allowed to transverse the network. Learning Mode must be
disabled on the Hub Tx/Rx modem, because if a computer on the remote sends a broadcast out
to the Hub, the modem learns that MAC is local – when in fact it is not.
Figure A-13. Point-to-Multipoint Using Switches
A wired-thru Ethernet redundancy example is shown in Figure A-14. When the CRS-300 1:10
Redundancy Switch backs up a faulted Traffic Modem, the physical port on the Switch does not
change, because the Ethernet connection is properly rerouted within the CRS-300 from the
Traffic Modem to the Redundant Modem.
A wired-around Ethernet redundancy example is shown for the CDM-700 User in Figure A-15.
When the CRS-300 1:10 Redundancy Switch backs up a faulted Traffic Modem, the Switch will
learn the new MAC address of the redundant unit and traffic will be passed again. This type of
architecture will slow down the switching time, because the Switch will need to re-learn the
correct port connection.