Comtech EF Data CDM-570 - Manual (Page 455)

CDM-570/570L Satellite Modem with Optional IP Module Revision 12
Appendix H MN/CDM570L.IOM
H–3
H.3 CDM-570/570L 1:1 IP Data Switching Functional Description
When the CDM-570/570L modem is using a serial data interface (for example, RS.422 or V.35),
the CRS-180 (or CRS-170A) 1:1 Redundancy Switch is used in conjunction with a Comtech 1:1
Data Switch module. When the CDM-570/570L modem is using the IP Module as the data
interface, there is no need for a 1:1 Data Switch module. As shown in Figure H-1, a standard
Ethernet Hub or Layer 2 Switch can be used (it is recommended to use a Layer 2 Switch).
Figure H-1. CDM-570 1:1 IP Redundancy
For CDM-570/570L IP 1:1 redundancy operation, both CDM-570/570L 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.