Networking Loops In Router Mode (With Ip Packet Processor - Comtech EF Data CDM-425 Installation And Operation Manual

I.2.3.2

Networking Loops in Router Mode (with IP Packet Processor)

Figure I-7. Point-to-Point Configuration in "Router Multipoint Hub" Working Mode
In a network where more than one working mode is set to "Router Multipoint Hub", care must be
taken in route table configuration to avoid Ethernet Networking Loops. Figure I-7 shows Point-to-
Multipoint configuration using the optional IP Packet Processor.
When a working mode is configured as "Router Multipoint Hub", the modem is allowed to egress
on the WAN interface the same packet as was originally ingressed from the WAN interface. This
is necessary to allow the Point-to-Multipoint configuration.
However, configuring more than one modem as a Router Hub across the WAN Interface, and
then adding default routes on either side – or any other invalid routes – will cause the same
packet to ping-pong between these two modems until TTL times out.
Appendix I
CDM-425 Advanced Satellite Modem
I–7
Revision 0
MN-CDM-425