11 Data Transfer related issues

11.1 ftp transfers die when I do a `put' but they work correctly if I `get' a file.A: Do you have the flow control enabled? Flow control is setby the pppd option `crtscts` for RTS/CTS and `xonxoff`for XON/XOFF. If you don't enable the flow control then you willprobably overrun the modem's buffers and this will prove to bedisastrous with vj header compression.

11.2 How do I use XON/XOFF for flow control?

A: The better flow control is CTS/RTS. However, if you can not do the hardware flow control with the signals CTS and RTS, then use XON/XOFF. The following three steps need to be performed.

You need to specify the pppd option xonxoff. This tells the pppd process to configure the serial device for XON/XOFF flow control and to load the two characters into the tty driver.
You need to specify the XON and XOFF characters in the pppd parameter asyncmap. This tells the remote system that is should quote the XON and XOFF characters when it wishes to send them to you. It is normally specified as the pppd parameter `asyncmap a0000'.
Of course, don't forget to tell the modem to use XON/XOFF flow control. My ZyXEL modem uses a sequence `&R1&H4' to do this.

11.3 Modem never seems to connect at a the high rate A: Put the desired rate as an option to the pppd process. Ifyou don't put the rate, then pppd process will use whatever rate isset currently at the time. Not all programs will restore all of theparameters to the previous settings properly upon exit. This may leadto strange rates configured for the serial device.

11.4 The proxyarp function fails to find the hardware address. A: Use the `ppp-2.1.2b.tar.gz` package. The `pppd`process was erroneously compiled with the 1.1.8 kernel and it used`Net-3` rather than `Net-2` definitions.

Additionally, you should refer to the proxy-ARP mini-HOWTO about the requirements for using proxy-ARP.

11.5 "`ioctl(TIOCGETD): I/O error`" or "`ioctl(PPPIOCSINPSIG): I/O error`". A: Look at the boot messages when you boot the kernel. If it says"`PPP version 0.1.2`" then you have an old version of the`ppp.c` driver.

If it says "PPP version 0.2.7" then you have the current driver, however, it was not built with the same set of defines for the ioctl numbers. Ensure that you have only one file called "ppp.h". It should be located in the kernel's include/linux directory. Once you have done this, rebuild the kernel and the pppd process.

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11 Data Transfer related issues

11.2 How do I use XON/XOFF for flow control?

11.4 The proxyarp function fails to find the hardware address. A: Use the ppp-2.1.2b.tar.gz package. The pppdprocess was erroneously compiled with the 1.1.8 kernel and it usedNet-3 rather than Net-2 definitions.

11.5 "ioctl(TIOCGETD): I/O error" or "ioctl(PPPIOCSINPSIG): I/O error". A: Look at the boot messages when you boot the kernel. If it says"PPP version 0.1.2" then you have an old version of theppp.c driver.

11.4 The proxyarp function fails to find the hardware address. A: Use the `ppp-2.1.2b.tar.gz` package. The `pppd`process was erroneously compiled with the 1.1.8 kernel and it used`Net-3` rather than `Net-2` definitions.

11.5 "`ioctl(TIOCGETD): I/O error`" or "`ioctl(PPPIOCSINPSIG): I/O error`". A: Look at the boot messages when you boot the kernel. If it says"`PPP version 0.1.2`" then you have an old version of the`ppp.c` driver.