Airlink Raven GPRS - Manual (Page 37)

Cingular GPRS Raven User Guide Version 2.01 29
Host Modes
PPP Mode
In PPP mode, the Raven acts as a PPP server, providing an IP address, and DNS
servers (if available) to the Host.
PPP mode is entered from the AT mode by using any of the following commands:
AT\APPP<CR>
ATDT10.0.0.1<CR>
ATDT10001<CR>
ATD#19788<CR>
CLIENT<CR>
In response to any of the preceding commands, the modem will respond with
CONNECT<CR><lf> and is ready for the host to begin PPP negotiations.
The IP received by the host in the resulting negotiation will either be a private (non-
routable) IP or a public (network-routable) IP provided by the network, depending
on the settings of *HOSTPRIVMODE [S300]. If *HOSTPRIVMODE=1, the value
of the private IP an be determined beforehand by querying S110. The private IP to
be used can be defined with the command AT*HOSTPRIVIP=192.168.100.33 sub-
stituting the desired IP address.
Using a private IP insulates the PPP client from changes in IP addresses of the
underlying network. The Raven will perform basic NAT-like address translation on
all packets.
If a public IP address is being used, any changes in the IP (as determined by the
wireless network) will result in the PPP link to the host being disconnected, requir-
ing the host to reinitiate it. The public IP is passed to the host in the PPP negotia-
tions, so when the network forces a change, the modem has to force the host to
renegotiate the PPP link to make this happen.
Slip Mode
SLIP mode is entered be using the "AT\ASLIP" command. As in PPP Mode, the IP
address that the host assumes is affected by the setting of S300. SLIP does not
negotiate the IP with the host, so before making a SLIP connection, the host SLIP
driver must be configured to use the IP specified by querying S110.