Net Node Software for TNC3

packet-net  How does a packet-radio network work?

info TNC3S  About the TNC3S packet-radio-controller for X-Net

X-Net N1URO  English documentation to X-Net by N1URO

X-Net Swiss-ARTG  X-Net pages of the Swiss-ARTG


Using X-Net adds powerful net-node functions to the TNC3 and TNC31. A net consisting of some of those TNC3 will configure itself automatically and optimise the way of the data packets through the net.

X-Net contains the normal hostmode-commands (WA8DED commands) of TNC3 Turbo-Firmware (ESCAPE-commands) and can therefore be operated as any other TNC. Depending on memory, X-net supports up to 50 logical Channels, e.g. you can connect a Mailbox which can be accessed by up to 50 users simultaneously.

X-Net contains (same as TNC3Box) a complete mailbox for up to 10 user-logins at the same time. The mailbox uses the usual DieBox commands (as Read, Send, User, Dir...), but does NOT support store-and-forward. The memory space for mail depends on the RAM installed (max. approx. 2MB). Mailbox within X-Net may be disabled if necessary.

X-Net supports NetNode (NetROM, TheNet)-network protovol as well as FlexNet Protokoll (RMNC). For TCP/IP applications the RS232-port may be configured as SLIP interface. The X-Net node supports TCP/IP routing

For configuration of a X-Net node, you establish a connect to the node (directly via the hostmode / RS232 interface or via radio link). Being sysop (authorisation is checked with a password algorithm), you can access all functions of the node from setting of single parameters to complete update of operating system and software.

TNC3 supports two modems and a RS232 interface. As the RS232 is normally not used with TNC at remote locations, you can add a third modem instead of RS232 to the third port to get a 3 port node with 3 modems.

To built nodes with more than 3 links, the TNC3 can be coupled with a simple serial high-speed bus with 1.6 Mbit/s capability or via Token-Ring (RS232 ring). One of the TNC3 in such a configuration will work as X-Net Master, the others as DLC-slaves. (Data-Link-Controller).

The X-Net protocol includes broadcast-messages, which are sent in regular time intervals and every time when there are major changes in the net structure detected. Incoming broadcast messages from adjacent nodes are interpreted and used to update the internal routing tables. The x-net routed system assures a best-possible way of the data packets through the network. If it happens that a node fails, data is rerouted via alternative routes. Overloaded links (due to heavy traffic) result in poor response times and are not used if faster links are available. The routing algorithms are stable, loops are avoided. X-net is the best network software for packet radio known.

X-Net supports networks with up to 1000 nodes. The maximum number of nodes which appear in the destination tables, can be configured. The fastest links are used first, worst nodes in the list are ignored.

X-Net supports SLIP protocol on RS232 and it is possible to use standard-TCP/IP software (e.g. Windows with Winsocket, Windows 95/98, Linux etc.). Use of the TCP/IP-services as FTP, HTTP, Telnet, SMTP, NNTP, POP, Ping etc. is no problem.

If you connect a X-Net node, you get a login-message, additional text from a file c.txt may be added. Up to 50 user may be connected to the node simultaneously.

External X-Net commands may be added by uploading programs to the node. Additional help-files may be stored for comfortable user help messages. 

All modems of TNC3 can send and receive data in fullduplex mode. A TX-tail time can be configured to e.g 1 minute, so the transmitter will stay active while data communication is in progress. As long as the transmitter is on constantly, there is no delay for RX-TX switching.

TNC3 with X-Net has a total data capability of up to 1.6 Mbit/s and supports ax.25 protocol speed modems up to  1 MBit/s ausgestattet werden, der gesamte Datendurchsatz kann bis etwa 100 kByte/Sekunde betragen

The minimal power drain of TNC3 (2-3 Watt, 200 mA at 12V) is important for solar powered stations. To run a PX with 300 Watts 365 days a year may cause considerable energy costs. As the TNC3 has no moving parts (fan, harddisc), there is no wear or inspection of these parts necessary.

If supply power happens to fail, all data remains in battery buffered CMOS-RAM and operation is resumed without data loss. The memory may be expanded to up to 2 MByte.

Packet nodes using TNC3 and X-Net are proven to be reliable and stable since years. X-Net systems are operative since years, some of them ever since 1995.

Development of X-Net is still going on to keep X-Net state of the art.

X-Net can also be used for commercial applications as process control, environment-control, remote control, remote-service etc. The dynamic routing results in very reliable and fail-safe data nets. X-Net is NOT limited for use in non-commercial systems, however commercial use is not free. Please contact SYMEK if you intend to use X-net in other than amateur radio applications.