You can define the protocol to use with each device in /etc/uucp/Devices. This specification is usually unnecessary because you can use the default or define the protocol with the particular system you are calling. Refer to UUCP /etc/uucp/Systems File for details. If you do specify the protocol, you must use the following form:
Type,Protocol [parameters]
For example, you can use TCP,te to specify the TCP/IP protocol.
The following table shows the available protocols for the Devices file.
Table 36–4 Protocols Used in /etc/uucp/Devices
Protocol |
Description |
---|---|
This protocol is commonly used for transmissions over TCP/IP and other reliable connections. t assumes error-free transmissions. |
|
This protocol is UUCP's native protocol. It is slow, reliable, and good for transmission over noisy telephone lines. |
|
This protocol assumes transmission over error-free channels that are message oriented (as opposed to byte-stream oriented, such as TCP/IP). |
|
This protocol is used for transmission over X.25 connections. f relies on flow control of the data stream, and is meant for working over links that can (almost) be guaranteed to be error-free, specifically X.25/PAD links. A checksum is enacted over a whole file only. If a transport fails, the receiver can request retransmission(s). |
Here is an example that shows a protocol designation for a device entry:
TCP,te - - Any TCP - |
This example indicates that, for device TCP, you should try to use the t protocol. If the other end refuses, use the e protocol.
Neither e nor t is appropriate for use over modems. Even if the modem assures error-free transmission, data can still be dropped between the modem and the CPU.