NAL Research Corporation (TN2009-25-V1.0)
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Although there are multiple gateways, a user is registered to a single gateway. The gateways perform
call connection setup and administrative duties such as billing and resource management. The satellite
constellation provides connectivity between users, from a user to the Iridium system gateway, and between
gateways. Within the Iridium network architecture, the satellites are cross-linked which allows ISU to ISU
communication independent of gateway intervention once the call connection is established.
There are currently two commercial Iridium gateways located in Arizona, United States and Fucino,
Italy. The U.S. government owns and operates an Iridium gateway located in Hawaii, United States. Each
gateway generates and controls all user information pertaining to its registered users, such as user identity,
geo-location and billing items. The gateway also provides connectivity from the Iridium system to the
terrestrial based networks such as the PSTN.
A.2 Description of the Iridium Network Data Capabilities
For data communications, the Iridium network supports five different modes of operation as shown in
Figure A1—dial-up data service, direct Internet connection, short-burst data (SBD), short-messaging service
(SMS) and router-based unrestricted digital internetworking connectivity solution (RUDICS).
Dial-up Data (DAV)
Direct Internet
SBD
SMS
RUDICS
Dial-up Data (DAV)
SMS, SBD
Internet
AZ, HI or Fucino
SBD, SMS
(e-mail)
RUDICS
Server
IP
Address
PSTN
Landline
Modem
Figure A1.
Iridium Network Data Capabilities.
