Mocomtech CDM-570 - Manual (Page 300)

CDM-570/570L Satellite Modem with Optional IP Module Revision 4
Typical IP Module Operation Setups MN/CDM570L.IOM
The first method does not require any additional CDM-IP modems than is described in
Figure 16-3, Router Mode, Point-to-Multipoint Diagram. Just by adding static routes,
traffic could be sent between Remote Site A and B. Remote site A and B would add a
static route for remote destination subnet, but since the path to the remotes must go
through the Hub, the Next Hop HDLC Address would be 0x01, not the HDLC address of
the Remote. Traffic from Remote B would be transmitted to Hub RX Only CDM-IP 2,
forwarded to Hub CDM-IP 1 and retransmitted to Remote A. With this method, all traffic
must go through a “double hop” in order to arrive at the destination.
To avoid the additional delay of the “double hop” method, an alternative method would
require an additional RX Only CDM-IP modem at remote site for every other remote site
connection needed. In Figure 16-4, Router Mode, Partial Mesh, 1½ Hop Diagram,
Remote Site B has added a RX Only CDM-IP and a static route to 10.20.0.0/16, Next
Hop 0x01 (through the Hub). Remote Site A has added a static route for 10.30.0.0/16,
Next Hop 0x03. To establish a connection between Remote A and B, Remote A would
reconfigure the TX frequency and data rate to set up a link with the Remote B RX Only
modem. The return path still must go from B to the Hub and then to A, but A has a direct
link to B, thus this is considered a 1½ hop link.
Additional RX Only or full duplex CDM-IP modems can be added at Remotes based
upon what 1½ hop link or single hop connections are required. Always use the following
guidelines:
1) All CDM-IP modems will list the Site HDLC as their first RX HDLC Address.
2) For Satellite routes, the Next Hop is the destination Site HDLC (unless there is not a
direct satellite link, whereas the Next Hop must be the Hub Site).
3) RX Only CDM-IP modems will need a default To Ethernet route to a duplex CDM-IP
Modem at the site in order to forward traffic.
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