Sierra Wireless DART 200 CDPD Modem manual Dart 200 Cdpd Modem User’s Guide Installation and Setup

DART 200 CDPD Modem User’s Guide 2 Installation and Setup

Table 2-2. Registration failure troubleshooting (cont.)

Condition	Result	Solution
	Code
Invalid IP	3 or 1 (on	1. If the side setting is OK, verify that the
Address	some	modem’s IP Address is correct, by
	systems)	using the AT\S? command to view the
		IP Address. If the modem has more
		than one IP Address in the table,
		verify that the active NEI, the one with
		the asterisk (*) to the left, is correct.
		This condition could also mean that
		the carrier did not activate this IP
		Address.
		2. Contact the carrier to ensure that the
		IP Address is valid and active
Expired IP	6	As CDPD networks grow, some carriers
Address		are concerned about unauthorized use of
		unused IP Addresses to gain access to the
		network. To minimize this likelihood an
		expiration time is used, usually a few hours
		long, on each new IP Address. If you are
		slow in registering a modem with a
		recently assigned IP Address, the
		expiration time period can be exceeded.
		Find out from your carrier if they employ
		this strategy, and if so register new IP
		Addresses promptly.
Authentication	4 or 5	Each IP Address has two credential values
(credentials)		associated with it: a sequential number and
problem		a random number. These numbers are
		initially set to zero at the MDIS when the
		IP Address is assigned to an end-user.
		When the end-user puts the IP Address into
		the modem these values are also set to
		zero.
		When the IP Address is registered, these
		values are compared at the MDIS to ensure
		that they match. If they do, a new random
		number is generated at the MDIS and
		returned to the modem, and both ends
		update their sequential numbers. On each
		subsequent registration these values are
		compared by the MDIS (before updating)
		to see that they match. The modem keeps
		these credentials separately for each slot in
		the NEI (IP Address) list.
		Problems can arise if the IP Address is
		reloaded after it was registered, or is being
		reused or shared among modems. Any of
		these activities will cause the modem

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