55
the connection to an ISP. This can either be governed by a log-on script, or else handled
automatically within the Internet protocol suite.
8.4.9.2 Connection logic
NETDIAL’s purpose is to dial up the Internet service provider (ISP) and establish an
authenticated connection before handing control back to the TCP/IP protocol stack, which can
then use that connection via the PPP network interface. When this sequence has completed, the
data packet that caused the connect sequence can finally be sent. NETDIAL handles these tasks
separately from any individual application, so that it is not necessary to duplicate the same code in
every component that might need to make an Internet connection.
Dialling involves:
•
looking up the current location, the current modem settings, and the current ISP in the
comms database
•
invoking the NETDIAL dialog server to obtain confirmation of these default items, as
required
•
in conjunction with EPOC’s DIAL component, ensuring that the phone number for the
current ISP is resolved, taking into account the current location and any other relevant
settings, such as phone type and charge card
•
establishing a connection to the telephony server, ETEL, which is responsible for
controlling the phone or modem and for establishing a telephone connection
•
after connection, optionally handling any logging on by using a text-mode script if
neither CHAP nor PAP authentication protocols are available over the data link protocol.
•
returning control to NIFMAN
8.4.9.3 User interface
8.4.9.3.1 At setup time
Because dialling involves lookup from the comms database, the relevant items must be set in
advance. As described previously, these is done through the Control Panel. Once all applicable
settings have been entered, the user can connect to the Internet from any Internet application on
the EPOC machine.
The Control Panel applications have been made as simple to use as possible. Whilst setting up
connections to most Internet service providers (ISPs) is now relatively trivial, setup information
on many popular ISPs — including telephone numbers and any special scripts — is nevertheless
made available with EPOC Internet applications, and is also shared on the Web sites of EPOC
OEMs. Likewise, settings for popular modem types are supplied. This means that most setup is a
simple matter of selection from lists of modems and ISPs.
8.4.9.3.2 At connection time
As well as initial setup from the control panel, it is important to provide some visible user
interface when a connection is made. There are several reasons for this:
•
for security reasons, the user may not have wished to include their user ID and password
in the ISP settings. If this is the case, they must be typed in at connect time.
•
as a connection is made, it is reassuring for the user to see feedback about the state of the
connection
•
because EPOC users are highly mobile, it is essential to be able to present a choice of
connection options
at connect time
rather than forcing the user to use the control panel
before starting to connect
For connection options and for authentication, the NETDIAL dialog server (NDDLGSVR)
provides a user interface. NETDIAL specifies an API which the dialog server then uses. All
functions in this API are asynchronous: they complete when the user dismisses the dialog.
Progress of a connection is not reported using the dialog server. An application which wishes to
report the progress of a connection must use the NIFMAN interface directly.
