Comtech EF Data CDM-625A Installation And Operation Manual page 612

CDM-625A Advanced Satellite Modem
Appendix K
Figure 16-1 shows the internal Ethernet architecture for the CDM-625A. The CDM-625A features
four built-in 10/100 BaseT Ethernet Ports (port configuration and statistics are available on a
per-port basis) connected to a single internal Ethernet Layer 2 Managed Switch.
K.2.2 Modes of Ethernet Operation
The Ethernet interface is configurable for Managed Switch Mode when the optional IP Packet
Processor is either not installed or installed but disabled; or in Router Mode or Managed
Switch Mode when the optional IP Packet Processor is installed and enabled . This interface
design allows for multiple customer Ethernet interfaces, as well as the convenience of daisy-
chaining together of multiple CDM-625As.
Additionally, because the M&C processor is connected to the internal Ethernet Switch, M&C
traffic is available via all LAN interfaces as well as via the over-the-air WAN interface.
K.2.3 Ethernet Networking Loops
Figure 16-2. Improper Use of External Ethernet Switch with CDM-625A
It should be noted that care must be taken to avoid Ethernet Networking Loops. Specifically,
the network operator must make sure to avoid connecting multiple ports of the CDM-625A to
the same external Ethernet switch, as shown in Figure 16-2.
Figure 16-3. Ethernet Networking Loop Example (Simplified)
Figure 16-3 shows a simplified version of this loop. As shown here, two switches have been
connected – each switch has two or more separate connections. This is not how the CDM-625A's
K–2
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MN-CDM625A