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DART 200 CDPD Modem User’s Guide | 5 DART Supported Protocols |
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NOTE:
How the UDP behaves is dependent on the auto answer mode in use.
∙The modem’s server listening port is disabled for the duration of any active client session. Incoming datagrams are received on the active session listening port and only from the destination address specified on the dial command until an escape is performed and an ATH is issued; reactivating the server’s normal listening port
∙If operating in backward compatibility mode, the destination port number on the ATDP command must be different from the modem’s server listening port
5.Following receipt of the connect message, application data written to the DART 200 through the
6.This data is assembled until a data forwarding condition, as described on p.
7.The DART 200 then attaches the UDP header and sends the datagram onto the network.
8.The datagram is directed by the network routers to the appropriate port on the designated server. If the server is not active when the datagram arrives it is lost, and the client is not informed.
In passive operation (server mode):
1.The UDP server listens on the configured port (2100 or *L specified) for an incoming datagram, then determines if the datagram is to be passed to the MAS and the
2.With auto answer disabled when a datagram is received by the UDP server, it first validates the source address (if the Friends Only option is specified), and if it is acceptable issues a RING result code. Refer for Auto Answer setup, p.
3.If an ATA command is not currently active, or is not issued within 60 seconds, the arriving datagram is discarded and the source address of the arriving datagram is not saved. No indication of this event is presented to the MAS. If the ATA command is, or becomes, active within the
∙A CONNECT result code is issued
∙The modem enters online mode
∙The source address is saved
∙The datagram is passed to the MAS
4.With auto answer enabled, as described in Auto Answer setup, p.
5.If the source address is acceptable then a CONNECT result code is issued.