IBM 19K5716 manual Connections to internet service providers ISPs

6. Confirm your entries by clicking OK and close the modem window.

Connections to internet service providers (ISPs)

There is no binding standard for ISDN dial-in access to the Internet via Internet providers. PPP/SLIP protocol variants, fixed or dynamically assigned IP addresses, static or dynamic DNS and a variety of authentication techniques make it impossible to set a universally valid Internet access configuration for the ISDN CAPI Port Device Driver.

For TCP/IP connections using the ISDN CAPI Port Device Driver, you must also use 32-bit client software (i.e., WWW browsers, FTP clients, etc.) rather than 16-bit applications for Windows 3.x. Otherwise, no connection to the 32-bit TCP/IP protocol stack integrated in Windows 95/98 is possible.

ISDN B-channel protocols and PPP variants

Many providers use the ”HDLC” or ”X.75” protocol on the ISDN B channel. Two protocol variants are used for PPP connections: "PPP over ISDN" in accordance with RFC 1618 (also known as synchronous PPP), and "PPP modem style" in accordance with RFC 1162 (also called asynchronous PPP).

Note: Please ask your Internet provider which combination of protocols and

authentication procedures are required for ISDN dial-in access.

Incorrect protocol settings either result in an immediate termination of the connection or prevent the ISDN connection from being established in the first place (error message: "The computer you are dialing in to is not answering.").

Setting modem registers for ISDN B-channel protocols and PPP: The virtual modem ISDN Internet (PPP over ISDN) is set by default to ”HDLC” and ”PPP over ISDN” according to RFC 1618. If a different configuration is requested by your Internet provider, you can change the B-channel ISDN protocol by setting the register "S31":

•S31=0X.75 protocol

•S31=1HDLC protocol (default)

•S31=2V.110 protocol

•S31=7V.120 protocol

The registers ”S41”, ”S42” and ”S43” can also be used to set the B1, B2 and B3 protocol layers individually. However, this is not necessary in most cases.

The PPP protocol variant used can be configured using register "S51":

•S51=0 asynchronous PPP ("modem style", RFC 1162)

•S51=1 synchronous PPP ("PPP over ISDN", RFC 1618)

180IBM ISDN PC Card:User’s Guide