User's Guide

The Operational View SB300 Series
Page 30 Proprietary and Confidential 2110059 Rev 1.0
5.1.2. Architecture
The major cellular carriers and equipment manufacturers created a trade group called the Wireless
Data Forum (formerly the CDPD Forum), that develops and publishes the governing technical
specifications for, and promotes the use of CDPD technology.
The CDPD network provides a Connectionless Network Service (CLNS), one in which the
network routes each packet individually within the network based on the destination address
carried in the packet and knowledge of the current network topology. It is often referred to as a
datagram service. From the user’s point of view, only the destination address is known, since the
CDPD network manages the packet routing required to reach the destination.
5.1.3. Modem Registration
5.1.3.1. The Network Entity Identifier (NEI)
Each user on the CDPD network is identified by a distinct Network Entity Identifier (NEI) which
is used by the CDPD network to route messages to the user. This is like an account on the
network.
Each NEI has a single home subdomain, where it is normally expected to be located within the
network. For example, a user’s home may be Las Vegas. Each modem may support more than
one NEI, each of which has a home subdomain, which may or may not be the same.
For example, you may wish to have three NEIs for the same modem; with these NEIs having
home subdomains in Las Vegas, New York, and Dallas (cities to which you travel regularly). You
may want to use the NEI corresponding to the city you are currently in. Alternatively, you may
want to support two separate NEIs that have the same subdomain, such as one for business use and
the other for personal use.
You may travel from a subdomain registered as the home area to a new serving area. The mobility
management functions provided within the CDPD network handles the routing of packets for
visiting modems in a manner that is transparent to you. If you have pre-arranged with your service
provider, you may obtain service in a serving area supported by another service provider.
The NEI used in the Sierra Wireless modem is the address assigned to the subscriber by the CDPD
network service provider. IP Addresses are 32-bit numbers that uniquely identify a given machine
(or end system) running the TCP/IP protocol suite. You need to have a unique address before you
can link in with the rest of the networked world.
The NEI for the Sierra Wireless modem may be installed using the WirelessExpert application
provided with the modem. Up to four unique NEIs can be supported in the Sierra Wireless
modem. The CDPD service provider will have a unique Service Provider Network Identifier
(SPNI). The CDPD service provider must supply the SPNI in numeric format to the CDPD
subscriber if you wish to restrict the modem to using that provider. The WirelessExpert
application can be used to enter SPNIs into a table of accepted providers.
5.1.3.2. Equipment Identifier (EID)
One parameter that the CDPD service providers require from the CDPD subscriber registering
their modem is the Equipment Identifier (EID). The EID is unique to each modem. Essentially, it
represents a unique electronic serial number for the subscriber device. No two devices in CDPD
can have the same EID.
The format used in representing this 48-bit EID is hex bytes separated by hyphens (e.g., 00-A0-
D5-00-00-7B). This is programmed into each Sierra Wireless modem at the factory, and the
subscriber can view the EID at any time using the Watcher or WirelessExpert applications
supplied with the modem, or the AT command AT+WPEID.
When a user initially signs up for service with a CDPD service provider, they will be required to
provide the service provider with the EID. This EID then becomes part of the CDPD Subscriber