Product specifications

CRS-170A L-Band 1:1 Redundancy Switch Revision 3
Introduction MN/CRS170A.IOM
1.2.1.1 IP Data 1:1 Switching Functional Description
A standard Ethernet Layer 2 Switch (provided by User) is needed when a CDM-625/570L/700/710
modem is configured for Ethernet terrestrial traffic.
Figure 1-4. IP 1:1 Redundancy
For IP 1:1 redundancy operation, both modems are assigned a unique M&C IP address on the
same subnet (in the diagram above, 172,18.10.21/24 and 172.18.10.22/24). A Traffic IP address
on the subnet is also assigned (172.18.10.20/24). Whichever modem is online, it will also assume
the Traffic IP.
When there is a switchover to the backup modem, this modem will now assume the Traffic IP. It
will also broadcast a “gratuitous ARP” which will tell all local devices to now associate a new
MAC address for the Traffic IP 172.18.10.20. Each device will update their ARP tables and
traffic will resume virtually instantaneously.
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