Product specifications

GSP-1620 Modem Product Specification
80-99240-1 Rev. D 3-11
For packet data service, roaming operation has the following
characteristics:
• Roaming within a Gateway service area can keep the PPP
session up the entire time, using dormant mode.
• Roaming between Gateway service areas is supported.
However, there is no hard hand-off capability between
separate Gateways. The PPP session will be dropped and
will have to be reestablished by the modem.
• Once on a new Gateway, automatic re-registration will be
performed and a new dynamic IP address will be assigned
to the modem.
• Roaming support for “fixed” IP addressing outside the
“home” Gateway service area is not currently supported.
Future design work to allow a DNS server to map IP
addresses to IMSIs is envisioned, which would permit
worldwide fixed IP address roaming.
If service alerts are enabled, a service alert is sent out the
Data/Control port whenever the Service Provider or Gateway
changes. This includes the modem changing from roaming to
home service area and vice versa.
Asynchronous Data Service
The GSP-1620 modem lets the application device (DTE)
connected to the modem originate or receive an asynchronous
data call. It can dial or be dialed by a modem at the host
server, connecting through the Globalstar Satellite
Communications System and the PSTN.
Figure 3-1 shows the various modems (the GSP-1620 DCE
modem, the Gateway Interworking Function [IWF] modem,
and the host modem) and other components involved in an
asynchronous data call.