RTES TCP/IP and NetBIOS Portal
XNET - QNET
(These components will be phased out gradually, in favor of EQNET/EXNET)

Overview

XNET and QNET are memory resident utilities that allow RTES device drivers to operate over a TCP/IP, UDP or NetBIOS connection.

For example, MODBUS will use XNET or QNET to communicate with a MODBUS device on a TCP/IP network. UNET will use XNET or QNET to communicate with other RTES and/or WinRTES computers using the UDP connection. RNET will use XNET or QNET to communicate with other RTES and/or WinRTES computers using the NetBIOS connection.

XNET provides the data link layers and operates with a "packet driver" to actually interface with network adapter - usually an Ethernet card.

QNET does not require a "packet driver". It includes a driver for NE2000 compatible Ethernet cards.

XNET and QNET also operate as BOOTP/DHCP server.

The diagrams below show the position of XNET or QNET in a connection between RTES and an external device on the network.

(1) The Ethernet adapter is NE2000 compatible.

[RTES] ----- [device driver] ----- [QNET] ====[[[Network]]]=====[Device]

(2) The Ethernet adapter is not NE2000 compatible.

[RTES] ----- [device driver] ----- [XNET] ---- [Packet Driver] ====[[[Network]]]====[Device]

Packet Drivers

Each Network Interface Card (NIC) is supplied with a packet driver. It is a file usually found in \Pktdrv directory of the driver disk. There are several packet drivers available for download on the Internet, on the websites of the hardware vendors as well as other organizations such as this one.

You may install 2 packet drivers and 2 copies of XNET.

Configuration file

The various parameters used by XNET and QNET are contained in a user-defined plain text file names QNET.CFG. (XNET uses QNET.CFG and QNET uses QNET.CFG)

The command line: XNET 1[cr] loads a second copy of XNET and uses QNET1.CFG as its configuration file.

In the configuration file, we define the following parameters. Some parameters are only relevant to QNET, others are only relevant to XNET, some are are relevant to both.

Typically, you define a parameter by typing a key letter, followed by the = sign, followed by the value - or list of values - you assign to that parameter. Values may be expressed as a decimal or a hexadecimal when preceeded with the letter 'x'. For example, 768 or x300 are the same value. Values are separated by a comma, a decimal point, a space, or a line feed.

Parameter

Key letter

Description

Default value

BOOTP client list

B

Define a list of clients that will query for an IP associated with their hardware address

B=n defines n clients
Each client is specified with a set of 10 numbers : the 1st 6 numbers are the hardware address, then the last 4 numbers are the IP.

B=0

Set packet driver interrupt number

I

Defines the interrupt number where XNET will find the packet driver you have installed.

Note: The following interrupt numbers are reserved by RTES for other purposes and cannot be used for the packet driver : x60 to x67, x7A,x7B, x80 to x83.

I=x70

Set IP for the TCP/IP stack

N

Sets the IP address to be used for sending and receiving IP packets.
The IP consists of 4 numbers (between 0 and 255).

N=111.111.111.111

I/O Port

P

Set I/O Port address assigned to the NE2000 Ethernet adapter.

Used by QNET

P=x300

IRQ number

Q

Set IRQ number assigned to the NE2000 Ethernet adapter.

Used by QNET.

Q=9

Socket expiry

T

Defines the time in seconds that XNET or QNET will maintain a socket that was not disconnected and is inactive.

T=600